| Message ID | 1526477827-10859-4-git-send-email-stefan.wahren@i2se.com |
|---|---|
| State | New |
| Headers | show |
| Series | hwmon: Add support for Raspberry Pi voltage sensor | expand |
Hi Stefan, On 16/05/18 14:37, Stefan Wahren wrote: > Currently there is no easy way to detect under-voltage conditions on a remote > Raspberry Pi. This hwmon driver retrieves the state of the under-voltage sensor > via mailbox interface. The handling based on Noralf's modifications to the > downstream firmware driver. In case of an under-voltage condition only an entry > is written to the kernel log. > > CC: "Noralf Trønnes" <noralf@tronnes.org> > Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com> > --- > drivers/hwmon/Kconfig | 10 ++ > drivers/hwmon/Makefile | 1 + > drivers/hwmon/raspberrypi-hwmon.c | 207 ++++++++++++++++++++++++++++++++++++++ > 3 files changed, 218 insertions(+) > create mode 100644 drivers/hwmon/raspberrypi-hwmon.c > > diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig > index 768aed5..7f935cf 100644 > --- a/drivers/hwmon/Kconfig > +++ b/drivers/hwmon/Kconfig > @@ -1298,6 +1298,16 @@ config SENSORS_PWM_FAN > This driver can also be built as a module. If so, the module > will be called pwm-fan. > > +config SENSORS_RASPBERRYPI_HWMON > + tristate "Raspberry Pi voltage monitor" > + depends on (ARCH_BCM2835 && RASPBERRYPI_FIRMWARE) || (COMPILE_TEST && !RASPBERRYPI_FIRMWARE) Since RASPBERRYPI_FIRMWARE already implies ARCH_BCM2835 (via BCM2835_MBOX), this is just a very roundabout way to say: depends on RASPBERRYPI_FIRMWARE || COMPILE_TEST Robin. > + help > + If you say yes here you get support for voltage sensor on the > + Raspberry Pi. > + > + This driver can also be built as a module. If so, the module > + will be called raspberrypi-hwmon. > + > config SENSORS_SHT15 > tristate "Sensiron humidity and temperature sensors. SHT15 and compat." > depends on GPIOLIB || COMPILE_TEST > diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile > index e7d52a3..a929770 100644 > --- a/drivers/hwmon/Makefile > +++ b/drivers/hwmon/Makefile > @@ -141,6 +141,7 @@ obj-$(CONFIG_SENSORS_PC87427) += pc87427.o > obj-$(CONFIG_SENSORS_PCF8591) += pcf8591.o > obj-$(CONFIG_SENSORS_POWR1220) += powr1220.o > obj-$(CONFIG_SENSORS_PWM_FAN) += pwm-fan.o > +obj-$(CONFIG_SENSORS_RASPBERRYPI_HWMON) += raspberrypi-hwmon.o > obj-$(CONFIG_SENSORS_S3C) += s3c-hwmon.o > obj-$(CONFIG_SENSORS_SCH56XX_COMMON)+= sch56xx-common.o > obj-$(CONFIG_SENSORS_SCH5627) += sch5627.o > diff --git a/drivers/hwmon/raspberrypi-hwmon.c b/drivers/hwmon/raspberrypi-hwmon.c > new file mode 100644 > index 0000000..2003f6c > --- /dev/null > +++ b/drivers/hwmon/raspberrypi-hwmon.c > @@ -0,0 +1,207 @@ > +// SPDX-License-Identifier: GPL-2.0+ > +/* > + * Raspberry Pi voltage sensor driver > + * > + * Based on firmware/raspberrypi.c by Noralf Trønnes > + * > + * Copyright (C) 2018 Stefan Wahren <stefan.wahren@i2se.com> > + */ > +#include <linux/device.h> > +#include <linux/err.h> > +#include <linux/hwmon.h> > +#include <linux/hwmon-sysfs.h> > +#include <linux/module.h> > +#include <linux/of_device.h> > +#include <linux/platform_device.h> > +#include <linux/slab.h> > +#include <linux/workqueue.h> > +#include <soc/bcm2835/raspberrypi-firmware.h> > + > +#define UNDERVOLTAGE_STICKY_BIT BIT(16) > + > +struct rpi_hwmon_data { > + struct device *hwmon_dev; > + struct rpi_firmware *fw; > + u32 last_throttled; > + struct delayed_work get_values_poll_work; > +}; > + > +static void rpi_firmware_get_throttled(struct rpi_hwmon_data *data) > +{ > + u32 new_uv, old_uv, value; > + int ret; > + > + /* Clear sticky bits */ > + value = 0xffff; > + > + ret = rpi_firmware_property(data->fw, RPI_FIRMWARE_GET_THROTTLED, > + &value, sizeof(value)); > + if (ret) { > + dev_err_once(data->hwmon_dev, "%s: Failed to get throttled (%d)\n", > + __func__, ret); > + return; > + } > + > + new_uv = value & UNDERVOLTAGE_STICKY_BIT; > + old_uv = data->last_throttled & UNDERVOLTAGE_STICKY_BIT; > + data->last_throttled = value; > + > + if (new_uv == old_uv) > + return; > + > + if (new_uv) > + dev_crit(data->hwmon_dev, "Under-voltage detected! (0x%08x)\n", > + value); > + else > + dev_info(data->hwmon_dev, "Voltage normalised (0x%08x)\n", > + value); > + > + sysfs_notify(&data->hwmon_dev->kobj, NULL, "in0_lcrit_alarm"); > +} > + > +static void get_values_poll(struct work_struct *work) > +{ > + struct rpi_hwmon_data *data; > + > + data = container_of(work, struct rpi_hwmon_data, > + get_values_poll_work.work); > + > + rpi_firmware_get_throttled(data); > + > + /* > + * We can't run faster than the sticky shift (100ms) since we get > + * flipping in the sticky bits that are cleared. > + */ > + schedule_delayed_work(&data->get_values_poll_work, 2 * HZ); > +} > + > +static int rpi_read(struct device *dev, enum hwmon_sensor_types type, > + u32 attr, int channel, long *val) > +{ > + struct rpi_hwmon_data *data = dev_get_drvdata(dev); > + > + if (type != hwmon_in) > + return -EOPNOTSUPP; > + > + if (attr != hwmon_in_lcrit_alarm) > + return -EOPNOTSUPP; > + > + if (channel) > + return -EOPNOTSUPP; > + > + *val = !!(data->last_throttled & UNDERVOLTAGE_STICKY_BIT); > + return 0; > +} > + > +static umode_t rpi_is_visible(const void *_data, enum hwmon_sensor_types type, > + u32 attr, int channel) > +{ > + if (type != hwmon_in) > + return 0; > + > + if (attr != hwmon_in_lcrit_alarm) > + return 0; > + > + if (channel) > + return 0; > + > + return 0444; > +} > + > +static const u32 rpi_in_config[] = { > + HWMON_I_LCRIT_ALARM, > + 0 > +}; > + > +static const struct hwmon_channel_info rpi_in = { > + .type = hwmon_in, > + .config = rpi_in_config, > +}; > + > +static const struct hwmon_channel_info *rpi_info[] = { > + &rpi_in, > + NULL > +}; > + > +static const struct hwmon_ops rpi_hwmon_ops = { > + .is_visible = rpi_is_visible, > + .read = rpi_read, > +}; > + > +static const struct hwmon_chip_info rpi_chip_info = { > + .ops = &rpi_hwmon_ops, > + .info = rpi_info, > +}; > + > +static int rpi_hwmon_probe(struct platform_device *pdev) > +{ > + struct device *dev = &pdev->dev; > + struct device_node *fw_node; > + struct rpi_hwmon_data *data; > + int ret; > + > + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); > + if (!data) > + return -ENOMEM; > + > + fw_node = of_get_parent(dev->of_node); > + if (!fw_node) { > + dev_err(dev, "Missing firmware node\n"); > + return -ENOENT; > + } > + > + data->fw = rpi_firmware_get(fw_node); > + of_node_put(fw_node); > + if (!data->fw) > + return -EPROBE_DEFER; > + > + ret = rpi_firmware_property(data->fw, RPI_FIRMWARE_GET_THROTTLED, > + &data->last_throttled, > + sizeof(data->last_throttled)); > + if (ret) { > + dev_info(dev, "Firmware doesn't support GET_THROTTLED\n"); > + return -EOPNOTSUPP; > + } > + > + data->hwmon_dev = devm_hwmon_device_register_with_info(dev, "rpi_volt", > + data, > + &rpi_chip_info, > + NULL); > + > + INIT_DELAYED_WORK(&data->get_values_poll_work, get_values_poll); > + platform_set_drvdata(pdev, data); > + > + if (!PTR_ERR_OR_ZERO(data->hwmon_dev)) > + schedule_delayed_work(&data->get_values_poll_work, 2 * HZ); > + > + return PTR_ERR_OR_ZERO(data->hwmon_dev); > +} > + > +static int rpi_hwmon_remove(struct platform_device *pdev) > +{ > + struct rpi_hwmon_data *data = platform_get_drvdata(pdev); > + > + cancel_delayed_work_sync(&data->get_values_poll_work); > + > + return 0; > +} > + > +static const struct of_device_id rpi_hwmon_of_match[] = { > + { .compatible = "raspberrypi,bcm2835-hwmon", }, > + { /* sentinel */}, > +}; > +MODULE_DEVICE_TABLE(of, rpi_hwmon_of_match); > + > +static struct platform_driver rpi_hwmon_driver = { > + .probe = rpi_hwmon_probe, > + .remove = rpi_hwmon_remove, > + .driver = { > + .name = "raspberrypi-hwmon", > + .of_match_table = rpi_hwmon_of_match, > + }, > +}; > +module_platform_driver(rpi_hwmon_driver); > + > +MODULE_AUTHOR("Stefan Wahren <stefan.wahren@i2se.com>"); > +MODULE_DESCRIPTION("Raspberry Pi voltage sensor driver"); > +MODULE_LICENSE("GPL v2"); >
On Wed, May 16, 2018 at 02:51:49PM +0100, Robin Murphy wrote: > Hi Stefan, > > On 16/05/18 14:37, Stefan Wahren wrote: > >Currently there is no easy way to detect under-voltage conditions on a remote > >Raspberry Pi. This hwmon driver retrieves the state of the under-voltage sensor > >via mailbox interface. The handling based on Noralf's modifications to the > >downstream firmware driver. In case of an under-voltage condition only an entry > >is written to the kernel log. > > > >CC: "Noralf Trønnes" <noralf@tronnes.org> > >Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com> > >--- > > drivers/hwmon/Kconfig | 10 ++ > > drivers/hwmon/Makefile | 1 + > > drivers/hwmon/raspberrypi-hwmon.c | 207 ++++++++++++++++++++++++++++++++++++++ > > 3 files changed, 218 insertions(+) > > create mode 100644 drivers/hwmon/raspberrypi-hwmon.c > > > >diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig > >index 768aed5..7f935cf 100644 > >--- a/drivers/hwmon/Kconfig > >+++ b/drivers/hwmon/Kconfig > >@@ -1298,6 +1298,16 @@ config SENSORS_PWM_FAN > > This driver can also be built as a module. If so, the module > > will be called pwm-fan. > >+config SENSORS_RASPBERRYPI_HWMON > >+ tristate "Raspberry Pi voltage monitor" > >+ depends on (ARCH_BCM2835 && RASPBERRYPI_FIRMWARE) || (COMPILE_TEST && !RASPBERRYPI_FIRMWARE) > > Since RASPBERRYPI_FIRMWARE already implies ARCH_BCM2835 (via BCM2835_MBOX), > this is just a very roundabout way to say: > > depends on RASPBERRYPI_FIRMWARE || COMPILE_TEST > That would permit SENSORS_RASPBERRYPI_HWMON=y combined with RASPBERRYPI_FIRMWARE=m, which AFAICS would result in a build error because include/soc/bcm2835/raspberrypi-firmware.h uses IS_ENABLED() and not IS_REACHABLE(). Guenter > Robin. > > >+ help > >+ If you say yes here you get support for voltage sensor on the > >+ Raspberry Pi. > >+ > >+ This driver can also be built as a module. If so, the module > >+ will be called raspberrypi-hwmon. > >+ > > config SENSORS_SHT15 > > tristate "Sensiron humidity and temperature sensors. SHT15 and compat." > > depends on GPIOLIB || COMPILE_TEST > >diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile > >index e7d52a3..a929770 100644 > >--- a/drivers/hwmon/Makefile > >+++ b/drivers/hwmon/Makefile > >@@ -141,6 +141,7 @@ obj-$(CONFIG_SENSORS_PC87427) += pc87427.o > > obj-$(CONFIG_SENSORS_PCF8591) += pcf8591.o > > obj-$(CONFIG_SENSORS_POWR1220) += powr1220.o > > obj-$(CONFIG_SENSORS_PWM_FAN) += pwm-fan.o > >+obj-$(CONFIG_SENSORS_RASPBERRYPI_HWMON) += raspberrypi-hwmon.o > > obj-$(CONFIG_SENSORS_S3C) += s3c-hwmon.o > > obj-$(CONFIG_SENSORS_SCH56XX_COMMON)+= sch56xx-common.o > > obj-$(CONFIG_SENSORS_SCH5627) += sch5627.o > >diff --git a/drivers/hwmon/raspberrypi-hwmon.c b/drivers/hwmon/raspberrypi-hwmon.c > >new file mode 100644 > >index 0000000..2003f6c > >--- /dev/null > >+++ b/drivers/hwmon/raspberrypi-hwmon.c > >@@ -0,0 +1,207 @@ > >+// SPDX-License-Identifier: GPL-2.0+ > >+/* > >+ * Raspberry Pi voltage sensor driver > >+ * > >+ * Based on firmware/raspberrypi.c by Noralf Trønnes > >+ * > >+ * Copyright (C) 2018 Stefan Wahren <stefan.wahren@i2se.com> > >+ */ > >+#include <linux/device.h> > >+#include <linux/err.h> > >+#include <linux/hwmon.h> > >+#include <linux/hwmon-sysfs.h> > >+#include <linux/module.h> > >+#include <linux/of_device.h> > >+#include <linux/platform_device.h> > >+#include <linux/slab.h> > >+#include <linux/workqueue.h> > >+#include <soc/bcm2835/raspberrypi-firmware.h> > >+ > >+#define UNDERVOLTAGE_STICKY_BIT BIT(16) > >+ > >+struct rpi_hwmon_data { > >+ struct device *hwmon_dev; > >+ struct rpi_firmware *fw; > >+ u32 last_throttled; > >+ struct delayed_work get_values_poll_work; > >+}; > >+ > >+static void rpi_firmware_get_throttled(struct rpi_hwmon_data *data) > >+{ > >+ u32 new_uv, old_uv, value; > >+ int ret; > >+ > >+ /* Clear sticky bits */ > >+ value = 0xffff; > >+ > >+ ret = rpi_firmware_property(data->fw, RPI_FIRMWARE_GET_THROTTLED, > >+ &value, sizeof(value)); > >+ if (ret) { > >+ dev_err_once(data->hwmon_dev, "%s: Failed to get throttled (%d)\n", > >+ __func__, ret); > >+ return; > >+ } > >+ > >+ new_uv = value & UNDERVOLTAGE_STICKY_BIT; > >+ old_uv = data->last_throttled & UNDERVOLTAGE_STICKY_BIT; > >+ data->last_throttled = value; > >+ > >+ if (new_uv == old_uv) > >+ return; > >+ > >+ if (new_uv) > >+ dev_crit(data->hwmon_dev, "Under-voltage detected! (0x%08x)\n", > >+ value); > >+ else > >+ dev_info(data->hwmon_dev, "Voltage normalised (0x%08x)\n", > >+ value); > >+ > >+ sysfs_notify(&data->hwmon_dev->kobj, NULL, "in0_lcrit_alarm"); > >+} > >+ > >+static void get_values_poll(struct work_struct *work) > >+{ > >+ struct rpi_hwmon_data *data; > >+ > >+ data = container_of(work, struct rpi_hwmon_data, > >+ get_values_poll_work.work); > >+ > >+ rpi_firmware_get_throttled(data); > >+ > >+ /* > >+ * We can't run faster than the sticky shift (100ms) since we get > >+ * flipping in the sticky bits that are cleared. > >+ */ > >+ schedule_delayed_work(&data->get_values_poll_work, 2 * HZ); > >+} > >+ > >+static int rpi_read(struct device *dev, enum hwmon_sensor_types type, > >+ u32 attr, int channel, long *val) > >+{ > >+ struct rpi_hwmon_data *data = dev_get_drvdata(dev); > >+ > >+ if (type != hwmon_in) > >+ return -EOPNOTSUPP; > >+ > >+ if (attr != hwmon_in_lcrit_alarm) > >+ return -EOPNOTSUPP; > >+ > >+ if (channel) > >+ return -EOPNOTSUPP; > >+ > >+ *val = !!(data->last_throttled & UNDERVOLTAGE_STICKY_BIT); > >+ return 0; > >+} > >+ > >+static umode_t rpi_is_visible(const void *_data, enum hwmon_sensor_types type, > >+ u32 attr, int channel) > >+{ > >+ if (type != hwmon_in) > >+ return 0; > >+ > >+ if (attr != hwmon_in_lcrit_alarm) > >+ return 0; > >+ > >+ if (channel) > >+ return 0; > >+ > >+ return 0444; > >+} > >+ > >+static const u32 rpi_in_config[] = { > >+ HWMON_I_LCRIT_ALARM, > >+ 0 > >+}; > >+ > >+static const struct hwmon_channel_info rpi_in = { > >+ .type = hwmon_in, > >+ .config = rpi_in_config, > >+}; > >+ > >+static const struct hwmon_channel_info *rpi_info[] = { > >+ &rpi_in, > >+ NULL > >+}; > >+ > >+static const struct hwmon_ops rpi_hwmon_ops = { > >+ .is_visible = rpi_is_visible, > >+ .read = rpi_read, > >+}; > >+ > >+static const struct hwmon_chip_info rpi_chip_info = { > >+ .ops = &rpi_hwmon_ops, > >+ .info = rpi_info, > >+}; > >+ > >+static int rpi_hwmon_probe(struct platform_device *pdev) > >+{ > >+ struct device *dev = &pdev->dev; > >+ struct device_node *fw_node; > >+ struct rpi_hwmon_data *data; > >+ int ret; > >+ > >+ data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); > >+ if (!data) > >+ return -ENOMEM; > >+ > >+ fw_node = of_get_parent(dev->of_node); > >+ if (!fw_node) { > >+ dev_err(dev, "Missing firmware node\n"); > >+ return -ENOENT; > >+ } > >+ > >+ data->fw = rpi_firmware_get(fw_node); > >+ of_node_put(fw_node); > >+ if (!data->fw) > >+ return -EPROBE_DEFER; > >+ > >+ ret = rpi_firmware_property(data->fw, RPI_FIRMWARE_GET_THROTTLED, > >+ &data->last_throttled, > >+ sizeof(data->last_throttled)); > >+ if (ret) { > >+ dev_info(dev, "Firmware doesn't support GET_THROTTLED\n"); > >+ return -EOPNOTSUPP; > >+ } > >+ > >+ data->hwmon_dev = devm_hwmon_device_register_with_info(dev, "rpi_volt", > >+ data, > >+ &rpi_chip_info, > >+ NULL); > >+ > >+ INIT_DELAYED_WORK(&data->get_values_poll_work, get_values_poll); > >+ platform_set_drvdata(pdev, data); > >+ > >+ if (!PTR_ERR_OR_ZERO(data->hwmon_dev)) > >+ schedule_delayed_work(&data->get_values_poll_work, 2 * HZ); > >+ > >+ return PTR_ERR_OR_ZERO(data->hwmon_dev); > >+} > >+ > >+static int rpi_hwmon_remove(struct platform_device *pdev) > >+{ > >+ struct rpi_hwmon_data *data = platform_get_drvdata(pdev); > >+ > >+ cancel_delayed_work_sync(&data->get_values_poll_work); > >+ > >+ return 0; > >+} > >+ > >+static const struct of_device_id rpi_hwmon_of_match[] = { > >+ { .compatible = "raspberrypi,bcm2835-hwmon", }, > >+ { /* sentinel */}, > >+}; > >+MODULE_DEVICE_TABLE(of, rpi_hwmon_of_match); > >+ > >+static struct platform_driver rpi_hwmon_driver = { > >+ .probe = rpi_hwmon_probe, > >+ .remove = rpi_hwmon_remove, > >+ .driver = { > >+ .name = "raspberrypi-hwmon", > >+ .of_match_table = rpi_hwmon_of_match, > >+ }, > >+}; > >+module_platform_driver(rpi_hwmon_driver); > >+ > >+MODULE_AUTHOR("Stefan Wahren <stefan.wahren@i2se.com>"); > >+MODULE_DESCRIPTION("Raspberry Pi voltage sensor driver"); > >+MODULE_LICENSE("GPL v2"); > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-hwmon" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, May 16, 2018 at 03:37:04PM +0200, Stefan Wahren wrote: > Currently there is no easy way to detect under-voltage conditions on a remote > Raspberry Pi. This hwmon driver retrieves the state of the under-voltage sensor > via mailbox interface. The handling based on Noralf's modifications to the > downstream firmware driver. In case of an under-voltage condition only an entry > is written to the kernel log. > My major concern is how this is displayed with the 'sensors' command. Can you test and report ? Of course, it would be much better if the firmware would also report the actual voltage, but I guess we can't have everything. More comments inline. Thanks, Guenter > CC: "Noralf Trønnes" <noralf@tronnes.org> > Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com> > --- > drivers/hwmon/Kconfig | 10 ++ > drivers/hwmon/Makefile | 1 + > drivers/hwmon/raspberrypi-hwmon.c | 207 ++++++++++++++++++++++++++++++++++++++ Please also provide Documentation/hwmon/raspberrypi-hwmon. > 3 files changed, 218 insertions(+) > create mode 100644 drivers/hwmon/raspberrypi-hwmon.c > > diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig > index 768aed5..7f935cf 100644 > --- a/drivers/hwmon/Kconfig > +++ b/drivers/hwmon/Kconfig > @@ -1298,6 +1298,16 @@ config SENSORS_PWM_FAN > This driver can also be built as a module. If so, the module > will be called pwm-fan. > > +config SENSORS_RASPBERRYPI_HWMON > + tristate "Raspberry Pi voltage monitor" > + depends on (ARCH_BCM2835 && RASPBERRYPI_FIRMWARE) || (COMPILE_TEST && !RASPBERRYPI_FIRMWARE) > + help > + If you say yes here you get support for voltage sensor on the > + Raspberry Pi. > + > + This driver can also be built as a module. If so, the module > + will be called raspberrypi-hwmon. > + > config SENSORS_SHT15 > tristate "Sensiron humidity and temperature sensors. SHT15 and compat." > depends on GPIOLIB || COMPILE_TEST > diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile > index e7d52a3..a929770 100644 > --- a/drivers/hwmon/Makefile > +++ b/drivers/hwmon/Makefile > @@ -141,6 +141,7 @@ obj-$(CONFIG_SENSORS_PC87427) += pc87427.o > obj-$(CONFIG_SENSORS_PCF8591) += pcf8591.o > obj-$(CONFIG_SENSORS_POWR1220) += powr1220.o > obj-$(CONFIG_SENSORS_PWM_FAN) += pwm-fan.o > +obj-$(CONFIG_SENSORS_RASPBERRYPI_HWMON) += raspberrypi-hwmon.o > obj-$(CONFIG_SENSORS_S3C) += s3c-hwmon.o > obj-$(CONFIG_SENSORS_SCH56XX_COMMON)+= sch56xx-common.o > obj-$(CONFIG_SENSORS_SCH5627) += sch5627.o > diff --git a/drivers/hwmon/raspberrypi-hwmon.c b/drivers/hwmon/raspberrypi-hwmon.c > new file mode 100644 > index 0000000..2003f6c > --- /dev/null > +++ b/drivers/hwmon/raspberrypi-hwmon.c > @@ -0,0 +1,207 @@ > +// SPDX-License-Identifier: GPL-2.0+ > +/* > + * Raspberry Pi voltage sensor driver > + * > + * Based on firmware/raspberrypi.c by Noralf Trønnes > + * > + * Copyright (C) 2018 Stefan Wahren <stefan.wahren@i2se.com> > + */ > +#include <linux/device.h> > +#include <linux/err.h> > +#include <linux/hwmon.h> > +#include <linux/hwmon-sysfs.h> Unnecessary include > +#include <linux/module.h> > +#include <linux/of_device.h> > +#include <linux/platform_device.h> > +#include <linux/slab.h> > +#include <linux/workqueue.h> > +#include <soc/bcm2835/raspberrypi-firmware.h> > + > +#define UNDERVOLTAGE_STICKY_BIT BIT(16) > + > +struct rpi_hwmon_data { > + struct device *hwmon_dev; > + struct rpi_firmware *fw; > + u32 last_throttled; > + struct delayed_work get_values_poll_work; > +}; > + > +static void rpi_firmware_get_throttled(struct rpi_hwmon_data *data) > +{ > + u32 new_uv, old_uv, value; > + int ret; > + > + /* Clear sticky bits */ Please make more explicit that this is a request/command sent to the firmware. > + value = 0xffff; > + > + ret = rpi_firmware_property(data->fw, RPI_FIRMWARE_GET_THROTTLED, > + &value, sizeof(value)); > + if (ret) { > + dev_err_once(data->hwmon_dev, "%s: Failed to get throttled (%d)\n", > + __func__, ret); The function name seems unnecessary. > + return; > + } > + > + new_uv = value & UNDERVOLTAGE_STICKY_BIT; > + old_uv = data->last_throttled & UNDERVOLTAGE_STICKY_BIT; > + data->last_throttled = value; > + > + if (new_uv == old_uv) > + return; > + > + if (new_uv) > + dev_crit(data->hwmon_dev, "Under-voltage detected! (0x%08x)\n", > + value); > + else > + dev_info(data->hwmon_dev, "Voltage normalised (0x%08x)\n", > + value); What value do those hex values provide to the user ? > + > + sysfs_notify(&data->hwmon_dev->kobj, NULL, "in0_lcrit_alarm"); > +} > + > +static void get_values_poll(struct work_struct *work) > +{ > + struct rpi_hwmon_data *data; > + > + data = container_of(work, struct rpi_hwmon_data, > + get_values_poll_work.work); > + > + rpi_firmware_get_throttled(data); > + > + /* > + * We can't run faster than the sticky shift (100ms) since we get > + * flipping in the sticky bits that are cleared. > + */ > + schedule_delayed_work(&data->get_values_poll_work, 2 * HZ); > +} > + > +static int rpi_read(struct device *dev, enum hwmon_sensor_types type, > + u32 attr, int channel, long *val) > +{ > + struct rpi_hwmon_data *data = dev_get_drvdata(dev); > + > + if (type != hwmon_in) > + return -EOPNOTSUPP; > + > + if (attr != hwmon_in_lcrit_alarm) > + return -EOPNOTSUPP; > + > + if (channel) > + return -EOPNOTSUPP; > + There is only one channel, one attribute, and one type supported. As such, the checks are unnecessary. > + *val = !!(data->last_throttled & UNDERVOLTAGE_STICKY_BIT); > + return 0; > +} > + > +static umode_t rpi_is_visible(const void *_data, enum hwmon_sensor_types type, > + u32 attr, int channel) > +{ > + if (type != hwmon_in) > + return 0; > + > + if (attr != hwmon_in_lcrit_alarm) > + return 0; > + > + if (channel) > + return 0; Same as above. In the list below, there is not a single conditional attribute. Given that, the checks should be unnecessary, and it should be sufficient to just return 0444. > + > + return 0444; > +} > + > +static const u32 rpi_in_config[] = { > + HWMON_I_LCRIT_ALARM, > + 0 > +}; > + > +static const struct hwmon_channel_info rpi_in = { > + .type = hwmon_in, > + .config = rpi_in_config, > +}; > + > +static const struct hwmon_channel_info *rpi_info[] = { > + &rpi_in, > + NULL > +}; > + > +static const struct hwmon_ops rpi_hwmon_ops = { > + .is_visible = rpi_is_visible, > + .read = rpi_read, > +}; > + > +static const struct hwmon_chip_info rpi_chip_info = { > + .ops = &rpi_hwmon_ops, > + .info = rpi_info, > +}; > + > +static int rpi_hwmon_probe(struct platform_device *pdev) > +{ > + struct device *dev = &pdev->dev; > + struct device_node *fw_node; > + struct rpi_hwmon_data *data; > + int ret; > + > + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); > + if (!data) > + return -ENOMEM; > + > + fw_node = of_get_parent(dev->of_node); > + if (!fw_node) { > + dev_err(dev, "Missing firmware node\n"); > + return -ENOENT; > + } > + > + data->fw = rpi_firmware_get(fw_node); > + of_node_put(fw_node); > + if (!data->fw) > + return -EPROBE_DEFER; > + > + ret = rpi_firmware_property(data->fw, RPI_FIRMWARE_GET_THROTTLED, > + &data->last_throttled, > + sizeof(data->last_throttled)); > + if (ret) { > + dev_info(dev, "Firmware doesn't support GET_THROTTLED\n"); If this is an error -> dev_err(). > + return -EOPNOTSUPP; or return -ENODEV. > + } > + > + data->hwmon_dev = devm_hwmon_device_register_with_info(dev, "rpi_volt", > + data, > + &rpi_chip_info, > + NULL); > + > + INIT_DELAYED_WORK(&data->get_values_poll_work, get_values_poll); > + platform_set_drvdata(pdev, data); > + > + if (!PTR_ERR_OR_ZERO(data->hwmon_dev)) > + schedule_delayed_work(&data->get_values_poll_work, 2 * HZ); > + > + return PTR_ERR_OR_ZERO(data->hwmon_dev); > +} > + > +static int rpi_hwmon_remove(struct platform_device *pdev) > +{ > + struct rpi_hwmon_data *data = platform_get_drvdata(pdev); > + > + cancel_delayed_work_sync(&data->get_values_poll_work); > + > + return 0; > +} > + > +static const struct of_device_id rpi_hwmon_of_match[] = { > + { .compatible = "raspberrypi,bcm2835-hwmon", }, > + { /* sentinel */}, > +}; > +MODULE_DEVICE_TABLE(of, rpi_hwmon_of_match); > + > +static struct platform_driver rpi_hwmon_driver = { > + .probe = rpi_hwmon_probe, > + .remove = rpi_hwmon_remove, > + .driver = { > + .name = "raspberrypi-hwmon", > + .of_match_table = rpi_hwmon_of_match, > + }, > +}; > +module_platform_driver(rpi_hwmon_driver); > + > +MODULE_AUTHOR("Stefan Wahren <stefan.wahren@i2se.com>"); > +MODULE_DESCRIPTION("Raspberry Pi voltage sensor driver"); > +MODULE_LICENSE("GPL v2"); > -- > 2.7.4 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-hwmon" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
On 16/05/18 19:05, Guenter Roeck wrote: > On Wed, May 16, 2018 at 02:51:49PM +0100, Robin Murphy wrote: >> Hi Stefan, >> >> On 16/05/18 14:37, Stefan Wahren wrote: >>> Currently there is no easy way to detect under-voltage conditions on a remote >>> Raspberry Pi. This hwmon driver retrieves the state of the under-voltage sensor >>> via mailbox interface. The handling based on Noralf's modifications to the >>> downstream firmware driver. In case of an under-voltage condition only an entry >>> is written to the kernel log. >>> >>> CC: "Noralf Trønnes" <noralf@tronnes.org> >>> Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com> >>> --- >>> drivers/hwmon/Kconfig | 10 ++ >>> drivers/hwmon/Makefile | 1 + >>> drivers/hwmon/raspberrypi-hwmon.c | 207 ++++++++++++++++++++++++++++++++++++++ >>> 3 files changed, 218 insertions(+) >>> create mode 100644 drivers/hwmon/raspberrypi-hwmon.c >>> >>> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig >>> index 768aed5..7f935cf 100644 >>> --- a/drivers/hwmon/Kconfig >>> +++ b/drivers/hwmon/Kconfig >>> @@ -1298,6 +1298,16 @@ config SENSORS_PWM_FAN >>> This driver can also be built as a module. If so, the module >>> will be called pwm-fan. >>> +config SENSORS_RASPBERRYPI_HWMON >>> + tristate "Raspberry Pi voltage monitor" >>> + depends on (ARCH_BCM2835 && RASPBERRYPI_FIRMWARE) || (COMPILE_TEST && !RASPBERRYPI_FIRMWARE) >> >> Since RASPBERRYPI_FIRMWARE already implies ARCH_BCM2835 (via BCM2835_MBOX), >> this is just a very roundabout way to say: >> >> depends on RASPBERRYPI_FIRMWARE || COMPILE_TEST >> > That would permit SENSORS_RASPBERRYPI_HWMON=y combined with > RASPBERRYPI_FIRMWARE=m, which AFAICS would result in a build error > because include/soc/bcm2835/raspberrypi-firmware.h uses IS_ENABLED() > and not IS_REACHABLE(). But that's only possible when COMPILE_TEST=y, where in any case there are stub definitions for the #else case in that header which should still be enough to build with, right? (and if not, that's probably its own bug) Nobody's expecting COMPILE_TEST configs to actually boot and work perfectly, are they? Robin.
Hi Guenter, > Guenter Roeck <linux@roeck-us.net> hat am 16. Mai 2018 um 20:21 geschrieben: > > > On Wed, May 16, 2018 at 03:37:04PM +0200, Stefan Wahren wrote: > > Currently there is no easy way to detect under-voltage conditions on a remote > > Raspberry Pi. This hwmon driver retrieves the state of the under-voltage sensor > > via mailbox interface. The handling based on Noralf's modifications to the > > downstream firmware driver. In case of an under-voltage condition only an entry > > is written to the kernel log. > > > > My major concern is how this is displayed with the 'sensors' command. > Can you test and report ? I get the following output: rpi_volt-isa-0000 Adapter: ISA adapter in0: N/A > > Of course, it would be much better if the firmware would also report > the actual voltage, but I guess we can't have everything. I think this isn't possible because the hardware only provide a binary value (GPIO). > > More comments inline. > > Thanks, > Guenter > > > CC: "Noralf Trønnes" <noralf@tronnes.org> > > Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com> > > --- > > drivers/hwmon/Kconfig | 10 ++ > > drivers/hwmon/Makefile | 1 + > > drivers/hwmon/raspberrypi-hwmon.c | 207 ++++++++++++++++++++++++++++++++++++++ > > Please also provide Documentation/hwmon/raspberrypi-hwmon. > > > 3 files changed, 218 insertions(+) > > create mode 100644 drivers/hwmon/raspberrypi-hwmon.c > > > > diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig > > index 768aed5..7f935cf 100644 > > --- a/drivers/hwmon/Kconfig > > +++ b/drivers/hwmon/Kconfig > > @@ -1298,6 +1298,16 @@ config SENSORS_PWM_FAN > > This driver can also be built as a module. If so, the module > > will be called pwm-fan. > > > > +config SENSORS_RASPBERRYPI_HWMON > > + tristate "Raspberry Pi voltage monitor" > > + depends on (ARCH_BCM2835 && RASPBERRYPI_FIRMWARE) || (COMPILE_TEST && !RASPBERRYPI_FIRMWARE) > > + help > > + If you say yes here you get support for voltage sensor on the > > + Raspberry Pi. > > + > > + This driver can also be built as a module. If so, the module > > + will be called raspberrypi-hwmon. > > + > > config SENSORS_SHT15 > > tristate "Sensiron humidity and temperature sensors. SHT15 and compat." > > depends on GPIOLIB || COMPILE_TEST > > diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile > > index e7d52a3..a929770 100644 > > --- a/drivers/hwmon/Makefile > > +++ b/drivers/hwmon/Makefile > > @@ -141,6 +141,7 @@ obj-$(CONFIG_SENSORS_PC87427) += pc87427.o > > obj-$(CONFIG_SENSORS_PCF8591) += pcf8591.o > > obj-$(CONFIG_SENSORS_POWR1220) += powr1220.o > > obj-$(CONFIG_SENSORS_PWM_FAN) += pwm-fan.o > > +obj-$(CONFIG_SENSORS_RASPBERRYPI_HWMON) += raspberrypi-hwmon.o > > obj-$(CONFIG_SENSORS_S3C) += s3c-hwmon.o > > obj-$(CONFIG_SENSORS_SCH56XX_COMMON)+= sch56xx-common.o > > obj-$(CONFIG_SENSORS_SCH5627) += sch5627.o > > diff --git a/drivers/hwmon/raspberrypi-hwmon.c b/drivers/hwmon/raspberrypi-hwmon.c > > new file mode 100644 > > index 0000000..2003f6c > > --- /dev/null > > +++ b/drivers/hwmon/raspberrypi-hwmon.c > > @@ -0,0 +1,207 @@ > > +// SPDX-License-Identifier: GPL-2.0+ > > +/* > > + * Raspberry Pi voltage sensor driver > > + * > > + * Based on firmware/raspberrypi.c by Noralf Trønnes > > + * > > + * Copyright (C) 2018 Stefan Wahren <stefan.wahren@i2se.com> > > + */ > > +#include <linux/device.h> > > +#include <linux/err.h> > > +#include <linux/hwmon.h> > > +#include <linux/hwmon-sysfs.h> > > Unnecessary include > > > +#include <linux/module.h> > > +#include <linux/of_device.h> > > +#include <linux/platform_device.h> > > +#include <linux/slab.h> > > +#include <linux/workqueue.h> > > +#include <soc/bcm2835/raspberrypi-firmware.h> > > + > > +#define UNDERVOLTAGE_STICKY_BIT BIT(16) > > + > > +struct rpi_hwmon_data { > > + struct device *hwmon_dev; > > + struct rpi_firmware *fw; > > + u32 last_throttled; > > + struct delayed_work get_values_poll_work; > > +}; > > + > > +static void rpi_firmware_get_throttled(struct rpi_hwmon_data *data) > > +{ > > + u32 new_uv, old_uv, value; > > + int ret; > > + > > + /* Clear sticky bits */ > > Please make more explicit that this is a request/command sent to the firmware. > > > + value = 0xffff; > > + > > + ret = rpi_firmware_property(data->fw, RPI_FIRMWARE_GET_THROTTLED, > > + &value, sizeof(value)); > > + if (ret) { > > + dev_err_once(data->hwmon_dev, "%s: Failed to get throttled (%d)\n", > > + __func__, ret); > > The function name seems unnecessary. > > > + return; > > + } > > + > > + new_uv = value & UNDERVOLTAGE_STICKY_BIT; > > + old_uv = data->last_throttled & UNDERVOLTAGE_STICKY_BIT; > > + data->last_throttled = value; > > + > > + if (new_uv == old_uv) > > + return; > > + > > + if (new_uv) > > + dev_crit(data->hwmon_dev, "Under-voltage detected! (0x%08x)\n", > > + value); > > + else > > + dev_info(data->hwmon_dev, "Voltage normalised (0x%08x)\n", > > + value); > > What value do those hex values provide to the user ? The actual definition of the bits can be found in the commit log of patch #1. But this isn't very helpful for an end user. > > > + > > + sysfs_notify(&data->hwmon_dev->kobj, NULL, "in0_lcrit_alarm"); > > +} > > + > > +static void get_values_poll(struct work_struct *work) > > +{ > > + struct rpi_hwmon_data *data; > > + > > + data = container_of(work, struct rpi_hwmon_data, > > + get_values_poll_work.work); > > + > > + rpi_firmware_get_throttled(data); > > + > > + /* > > + * We can't run faster than the sticky shift (100ms) since we get > > + * flipping in the sticky bits that are cleared. > > + */ > > + schedule_delayed_work(&data->get_values_poll_work, 2 * HZ); > > +} > > + > > +static int rpi_read(struct device *dev, enum hwmon_sensor_types type, > > + u32 attr, int channel, long *val) > > +{ > > + struct rpi_hwmon_data *data = dev_get_drvdata(dev); > > + > > + if (type != hwmon_in) > > + return -EOPNOTSUPP; > > + > > + if (attr != hwmon_in_lcrit_alarm) > > + return -EOPNOTSUPP; > > + > > + if (channel) > > + return -EOPNOTSUPP; > > + > There is only one channel, one attribute, and one type supported. > As such, the checks are unnecessary. > > > + *val = !!(data->last_throttled & UNDERVOLTAGE_STICKY_BIT); > > + return 0; > > +} > > + > > +static umode_t rpi_is_visible(const void *_data, enum hwmon_sensor_types type, > > + u32 attr, int channel) > > +{ > > + if (type != hwmon_in) > > + return 0; > > + > > + if (attr != hwmon_in_lcrit_alarm) > > + return 0; > > + > > + if (channel) > > + return 0; > > Same as above. In the list below, there is not a single conditional attribute. > Given that, the checks should be unnecessary, and it should be sufficient to > just return 0444. > > > + > > + return 0444; > > +} > > + > > +static const u32 rpi_in_config[] = { > > + HWMON_I_LCRIT_ALARM, > > + 0 > > +}; > > + > > +static const struct hwmon_channel_info rpi_in = { > > + .type = hwmon_in, > > + .config = rpi_in_config, > > +}; > > + > > +static const struct hwmon_channel_info *rpi_info[] = { > > + &rpi_in, > > + NULL > > +}; > > + > > +static const struct hwmon_ops rpi_hwmon_ops = { > > + .is_visible = rpi_is_visible, > > + .read = rpi_read, > > +}; > > + > > +static const struct hwmon_chip_info rpi_chip_info = { > > + .ops = &rpi_hwmon_ops, > > + .info = rpi_info, > > +}; > > + > > +static int rpi_hwmon_probe(struct platform_device *pdev) > > +{ > > + struct device *dev = &pdev->dev; > > + struct device_node *fw_node; > > + struct rpi_hwmon_data *data; > > + int ret; > > + > > + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); > > + if (!data) > > + return -ENOMEM; > > + > > + fw_node = of_get_parent(dev->of_node); > > + if (!fw_node) { > > + dev_err(dev, "Missing firmware node\n"); > > + return -ENOENT; > > + } > > + > > + data->fw = rpi_firmware_get(fw_node); > > + of_node_put(fw_node); > > + if (!data->fw) > > + return -EPROBE_DEFER; > > + > > + ret = rpi_firmware_property(data->fw, RPI_FIRMWARE_GET_THROTTLED, > > + &data->last_throttled, > > + sizeof(data->last_throttled)); > > + if (ret) { > > + dev_info(dev, "Firmware doesn't support GET_THROTTLED\n"); > > If this is an error -> dev_err(). I wasn't sure. If the firmware is too old, we cannot provide this feature and it's a waste of resources to load this driver. On the other side i don't want to confuse people this is something bad. Stefan > > > + return -EOPNOTSUPP; > > or return -ENODEV. > > > + } > > + > > + data->hwmon_dev = devm_hwmon_device_register_with_info(dev, "rpi_volt", > > + data, > > + &rpi_chip_info, > > + NULL); > > + > > + INIT_DELAYED_WORK(&data->get_values_poll_work, get_values_poll); > > + platform_set_drvdata(pdev, data); > > + > > + if (!PTR_ERR_OR_ZERO(data->hwmon_dev)) > > + schedule_delayed_work(&data->get_values_poll_work, 2 * HZ); > > + > > + return PTR_ERR_OR_ZERO(data->hwmon_dev); > > +} > > + > > +static int rpi_hwmon_remove(struct platform_device *pdev) > > +{ > > + struct rpi_hwmon_data *data = platform_get_drvdata(pdev); > > + > > + cancel_delayed_work_sync(&data->get_values_poll_work); > > + > > + return 0; > > +} > > + > > +static const struct of_device_id rpi_hwmon_of_match[] = { > > + { .compatible = "raspberrypi,bcm2835-hwmon", }, > > + { /* sentinel */}, > > +}; > > +MODULE_DEVICE_TABLE(of, rpi_hwmon_of_match); > > + > > +static struct platform_driver rpi_hwmon_driver = { > > + .probe = rpi_hwmon_probe, > > + .remove = rpi_hwmon_remove, > > + .driver = { > > + .name = "raspberrypi-hwmon", > > + .of_match_table = rpi_hwmon_of_match, > > + }, > > +}; > > +module_platform_driver(rpi_hwmon_driver); > > + > > +MODULE_AUTHOR("Stefan Wahren <stefan.wahren@i2se.com>"); > > +MODULE_DESCRIPTION("Raspberry Pi voltage sensor driver"); > > +MODULE_LICENSE("GPL v2"); > > -- > > 2.7.4 > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-hwmon" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
On Wed, May 16, 2018 at 09:59:01PM +0200, Stefan Wahren wrote: > Hi Guenter, > > > Guenter Roeck <linux@roeck-us.net> hat am 16. Mai 2018 um 20:21 geschrieben: > > > > > > On Wed, May 16, 2018 at 03:37:04PM +0200, Stefan Wahren wrote: > > > Currently there is no easy way to detect under-voltage conditions on a remote > > > Raspberry Pi. This hwmon driver retrieves the state of the under-voltage sensor > > > via mailbox interface. The handling based on Noralf's modifications to the > > > downstream firmware driver. In case of an under-voltage condition only an entry > > > is written to the kernel log. > > > > > > > My major concern is how this is displayed with the 'sensors' command. > > Can you test and report ? > > I get the following output: > rpi_volt-isa-0000 > Adapter: ISA adapter > in0: N/A > Ok, that works. > > > > Of course, it would be much better if the firmware would also report > > the actual voltage, but I guess we can't have everything. > > I think this isn't possible because the hardware only provide a binary value (GPIO). > > > > > More comments inline. > > > > Thanks, > > Guenter > > > > > CC: "Noralf Trønnes" <noralf@tronnes.org> > > > Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com> > > > --- > > > drivers/hwmon/Kconfig | 10 ++ > > > drivers/hwmon/Makefile | 1 + > > > drivers/hwmon/raspberrypi-hwmon.c | 207 ++++++++++++++++++++++++++++++++++++++ > > > > Please also provide Documentation/hwmon/raspberrypi-hwmon. > > > > > 3 files changed, 218 insertions(+) > > > create mode 100644 drivers/hwmon/raspberrypi-hwmon.c > > > > > > diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig > > > index 768aed5..7f935cf 100644 > > > --- a/drivers/hwmon/Kconfig > > > +++ b/drivers/hwmon/Kconfig > > > @@ -1298,6 +1298,16 @@ config SENSORS_PWM_FAN > > > This driver can also be built as a module. If so, the module > > > will be called pwm-fan. > > > > > > +config SENSORS_RASPBERRYPI_HWMON > > > + tristate "Raspberry Pi voltage monitor" > > > + depends on (ARCH_BCM2835 && RASPBERRYPI_FIRMWARE) || (COMPILE_TEST && !RASPBERRYPI_FIRMWARE) > > > + help > > > + If you say yes here you get support for voltage sensor on the > > > + Raspberry Pi. > > > + > > > + This driver can also be built as a module. If so, the module > > > + will be called raspberrypi-hwmon. > > > + > > > config SENSORS_SHT15 > > > tristate "Sensiron humidity and temperature sensors. SHT15 and compat." > > > depends on GPIOLIB || COMPILE_TEST > > > diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile > > > index e7d52a3..a929770 100644 > > > --- a/drivers/hwmon/Makefile > > > +++ b/drivers/hwmon/Makefile > > > @@ -141,6 +141,7 @@ obj-$(CONFIG_SENSORS_PC87427) += pc87427.o > > > obj-$(CONFIG_SENSORS_PCF8591) += pcf8591.o > > > obj-$(CONFIG_SENSORS_POWR1220) += powr1220.o > > > obj-$(CONFIG_SENSORS_PWM_FAN) += pwm-fan.o > > > +obj-$(CONFIG_SENSORS_RASPBERRYPI_HWMON) += raspberrypi-hwmon.o > > > obj-$(CONFIG_SENSORS_S3C) += s3c-hwmon.o > > > obj-$(CONFIG_SENSORS_SCH56XX_COMMON)+= sch56xx-common.o > > > obj-$(CONFIG_SENSORS_SCH5627) += sch5627.o > > > diff --git a/drivers/hwmon/raspberrypi-hwmon.c b/drivers/hwmon/raspberrypi-hwmon.c > > > new file mode 100644 > > > index 0000000..2003f6c > > > --- /dev/null > > > +++ b/drivers/hwmon/raspberrypi-hwmon.c > > > @@ -0,0 +1,207 @@ > > > +// SPDX-License-Identifier: GPL-2.0+ > > > +/* > > > + * Raspberry Pi voltage sensor driver > > > + * > > > + * Based on firmware/raspberrypi.c by Noralf Trønnes > > > + * > > > + * Copyright (C) 2018 Stefan Wahren <stefan.wahren@i2se.com> > > > + */ > > > +#include <linux/device.h> > > > +#include <linux/err.h> > > > +#include <linux/hwmon.h> > > > +#include <linux/hwmon-sysfs.h> > > > > Unnecessary include > > > > > +#include <linux/module.h> > > > +#include <linux/of_device.h> > > > +#include <linux/platform_device.h> > > > +#include <linux/slab.h> > > > +#include <linux/workqueue.h> > > > +#include <soc/bcm2835/raspberrypi-firmware.h> > > > + > > > +#define UNDERVOLTAGE_STICKY_BIT BIT(16) > > > + > > > +struct rpi_hwmon_data { > > > + struct device *hwmon_dev; > > > + struct rpi_firmware *fw; > > > + u32 last_throttled; > > > + struct delayed_work get_values_poll_work; > > > +}; > > > + > > > +static void rpi_firmware_get_throttled(struct rpi_hwmon_data *data) > > > +{ > > > + u32 new_uv, old_uv, value; > > > + int ret; > > > + > > > + /* Clear sticky bits */ > > > > Please make more explicit that this is a request/command sent to the firmware. > > > > > + value = 0xffff; > > > + > > > + ret = rpi_firmware_property(data->fw, RPI_FIRMWARE_GET_THROTTLED, > > > + &value, sizeof(value)); > > > + if (ret) { > > > + dev_err_once(data->hwmon_dev, "%s: Failed to get throttled (%d)\n", > > > + __func__, ret); > > > > The function name seems unnecessary. > > > > > + return; > > > + } > > > + > > > + new_uv = value & UNDERVOLTAGE_STICKY_BIT; > > > + old_uv = data->last_throttled & UNDERVOLTAGE_STICKY_BIT; > > > + data->last_throttled = value; > > > + > > > + if (new_uv == old_uv) > > > + return; > > > + > > > + if (new_uv) > > > + dev_crit(data->hwmon_dev, "Under-voltage detected! (0x%08x)\n", > > > + value); > > > + else > > > + dev_info(data->hwmon_dev, "Voltage normalised (0x%08x)\n", > > > + value); > > > > What value do those hex values provide to the user ? > > The actual definition of the bits can be found in the commit log of patch #1. But this isn't very helpful for an end user. > I would suggest to drop the value from the log. > > > > > + > > > + sysfs_notify(&data->hwmon_dev->kobj, NULL, "in0_lcrit_alarm"); > > > +} > > > + > > > +static void get_values_poll(struct work_struct *work) > > > +{ > > > + struct rpi_hwmon_data *data; > > > + > > > + data = container_of(work, struct rpi_hwmon_data, > > > + get_values_poll_work.work); > > > + > > > + rpi_firmware_get_throttled(data); > > > + > > > + /* > > > + * We can't run faster than the sticky shift (100ms) since we get > > > + * flipping in the sticky bits that are cleared. > > > + */ > > > + schedule_delayed_work(&data->get_values_poll_work, 2 * HZ); > > > +} > > > + > > > +static int rpi_read(struct device *dev, enum hwmon_sensor_types type, > > > + u32 attr, int channel, long *val) > > > +{ > > > + struct rpi_hwmon_data *data = dev_get_drvdata(dev); > > > + > > > + if (type != hwmon_in) > > > + return -EOPNOTSUPP; > > > + > > > + if (attr != hwmon_in_lcrit_alarm) > > > + return -EOPNOTSUPP; > > > + > > > + if (channel) > > > + return -EOPNOTSUPP; > > > + > > There is only one channel, one attribute, and one type supported. > > As such, the checks are unnecessary. > > > > > + *val = !!(data->last_throttled & UNDERVOLTAGE_STICKY_BIT); > > > + return 0; > > > +} > > > + > > > +static umode_t rpi_is_visible(const void *_data, enum hwmon_sensor_types type, > > > + u32 attr, int channel) > > > +{ > > > + if (type != hwmon_in) > > > + return 0; > > > + > > > + if (attr != hwmon_in_lcrit_alarm) > > > + return 0; > > > + > > > + if (channel) > > > + return 0; > > > > Same as above. In the list below, there is not a single conditional attribute. > > Given that, the checks should be unnecessary, and it should be sufficient to > > just return 0444. > > > > > + > > > + return 0444; > > > +} > > > + > > > +static const u32 rpi_in_config[] = { > > > + HWMON_I_LCRIT_ALARM, > > > + 0 > > > +}; > > > + > > > +static const struct hwmon_channel_info rpi_in = { > > > + .type = hwmon_in, > > > + .config = rpi_in_config, > > > +}; > > > + > > > +static const struct hwmon_channel_info *rpi_info[] = { > > > + &rpi_in, > > > + NULL > > > +}; > > > + > > > +static const struct hwmon_ops rpi_hwmon_ops = { > > > + .is_visible = rpi_is_visible, > > > + .read = rpi_read, > > > +}; > > > + > > > +static const struct hwmon_chip_info rpi_chip_info = { > > > + .ops = &rpi_hwmon_ops, > > > + .info = rpi_info, > > > +}; > > > + > > > +static int rpi_hwmon_probe(struct platform_device *pdev) > > > +{ > > > + struct device *dev = &pdev->dev; > > > + struct device_node *fw_node; > > > + struct rpi_hwmon_data *data; > > > + int ret; > > > + > > > + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); > > > + if (!data) > > > + return -ENOMEM; > > > + > > > + fw_node = of_get_parent(dev->of_node); > > > + if (!fw_node) { > > > + dev_err(dev, "Missing firmware node\n"); > > > + return -ENOENT; > > > + } > > > + > > > + data->fw = rpi_firmware_get(fw_node); > > > + of_node_put(fw_node); > > > + if (!data->fw) > > > + return -EPROBE_DEFER; > > > + > > > + ret = rpi_firmware_property(data->fw, RPI_FIRMWARE_GET_THROTTLED, > > > + &data->last_throttled, > > > + sizeof(data->last_throttled)); > > > + if (ret) { > > > + dev_info(dev, "Firmware doesn't support GET_THROTTLED\n"); > > > > If this is an error -> dev_err(). > > I wasn't sure. If the firmware is too old, we cannot provide this feature and it's a waste of resources to load this driver. On the other side i don't want to confuse people this is something bad. > Then I would suggest to return -ENODEV. Guenter > Stefan > > > > > > + return -EOPNOTSUPP; > > > > or return -ENODEV. > > > > > + } > > > + > > > + data->hwmon_dev = devm_hwmon_device_register_with_info(dev, "rpi_volt", > > > + data, > > > + &rpi_chip_info, > > > + NULL); > > > + > > > + INIT_DELAYED_WORK(&data->get_values_poll_work, get_values_poll); > > > + platform_set_drvdata(pdev, data); > > > + > > > + if (!PTR_ERR_OR_ZERO(data->hwmon_dev)) > > > + schedule_delayed_work(&data->get_values_poll_work, 2 * HZ); > > > + > > > + return PTR_ERR_OR_ZERO(data->hwmon_dev); > > > +} > > > + > > > +static int rpi_hwmon_remove(struct platform_device *pdev) > > > +{ > > > + struct rpi_hwmon_data *data = platform_get_drvdata(pdev); > > > + > > > + cancel_delayed_work_sync(&data->get_values_poll_work); > > > + > > > + return 0; > > > +} > > > + > > > +static const struct of_device_id rpi_hwmon_of_match[] = { > > > + { .compatible = "raspberrypi,bcm2835-hwmon", }, > > > + { /* sentinel */}, > > > +}; > > > +MODULE_DEVICE_TABLE(of, rpi_hwmon_of_match); > > > + > > > +static struct platform_driver rpi_hwmon_driver = { > > > + .probe = rpi_hwmon_probe, > > > + .remove = rpi_hwmon_remove, > > > + .driver = { > > > + .name = "raspberrypi-hwmon", > > > + .of_match_table = rpi_hwmon_of_match, > > > + }, > > > +}; > > > +module_platform_driver(rpi_hwmon_driver); > > > + > > > +MODULE_AUTHOR("Stefan Wahren <stefan.wahren@i2se.com>"); > > > +MODULE_DESCRIPTION("Raspberry Pi voltage sensor driver"); > > > +MODULE_LICENSE("GPL v2"); > > > -- > > > 2.7.4 > > > > > > -- > > > To unsubscribe from this list: send the line "unsubscribe linux-hwmon" in > > > the body of a message to majordomo@vger.kernel.org > > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > > > _______________________________________________ > > linux-arm-kernel mailing list > > linux-arm-kernel@lists.infradead.org > > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
Guenter Roeck <linux@roeck-us.net> writes: > On Wed, May 16, 2018 at 09:59:01PM +0200, Stefan Wahren wrote: >> Hi Guenter, >> >> > Guenter Roeck <linux@roeck-us.net> hat am 16. Mai 2018 um 20:21 geschrieben: >> > >> > >> > On Wed, May 16, 2018 at 03:37:04PM +0200, Stefan Wahren wrote: >> > > Currently there is no easy way to detect under-voltage conditions on a remote >> > > Raspberry Pi. This hwmon driver retrieves the state of the under-voltage sensor >> > > via mailbox interface. The handling based on Noralf's modifications to the >> > > downstream firmware driver. In case of an under-voltage condition only an entry >> > > is written to the kernel log. >> > > >> > >> > My major concern is how this is displayed with the 'sensors' command. >> > Can you test and report ? >> >> I get the following output: >> rpi_volt-isa-0000 >> Adapter: ISA adapter >> in0: N/A >> > Ok, that works. Thanks for the quick review on this, Guenter! This driver is going to help save a lot of people debugging time on rpis in the upstream kernel.
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig index 768aed5..7f935cf 100644 --- a/drivers/hwmon/Kconfig +++ b/drivers/hwmon/Kconfig @@ -1298,6 +1298,16 @@ config SENSORS_PWM_FAN This driver can also be built as a module. If so, the module will be called pwm-fan. +config SENSORS_RASPBERRYPI_HWMON + tristate "Raspberry Pi voltage monitor" + depends on (ARCH_BCM2835 && RASPBERRYPI_FIRMWARE) || (COMPILE_TEST && !RASPBERRYPI_FIRMWARE) + help + If you say yes here you get support for voltage sensor on the + Raspberry Pi. + + This driver can also be built as a module. If so, the module + will be called raspberrypi-hwmon. + config SENSORS_SHT15 tristate "Sensiron humidity and temperature sensors. SHT15 and compat." depends on GPIOLIB || COMPILE_TEST diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile index e7d52a3..a929770 100644 --- a/drivers/hwmon/Makefile +++ b/drivers/hwmon/Makefile @@ -141,6 +141,7 @@ obj-$(CONFIG_SENSORS_PC87427) += pc87427.o obj-$(CONFIG_SENSORS_PCF8591) += pcf8591.o obj-$(CONFIG_SENSORS_POWR1220) += powr1220.o obj-$(CONFIG_SENSORS_PWM_FAN) += pwm-fan.o +obj-$(CONFIG_SENSORS_RASPBERRYPI_HWMON) += raspberrypi-hwmon.o obj-$(CONFIG_SENSORS_S3C) += s3c-hwmon.o obj-$(CONFIG_SENSORS_SCH56XX_COMMON)+= sch56xx-common.o obj-$(CONFIG_SENSORS_SCH5627) += sch5627.o diff --git a/drivers/hwmon/raspberrypi-hwmon.c b/drivers/hwmon/raspberrypi-hwmon.c new file mode 100644 index 0000000..2003f6c --- /dev/null +++ b/drivers/hwmon/raspberrypi-hwmon.c @@ -0,0 +1,207 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Raspberry Pi voltage sensor driver + * + * Based on firmware/raspberrypi.c by Noralf Trønnes + * + * Copyright (C) 2018 Stefan Wahren <stefan.wahren@i2se.com> + */ +#include <linux/device.h> +#include <linux/err.h> +#include <linux/hwmon.h> +#include <linux/hwmon-sysfs.h> +#include <linux/module.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/workqueue.h> +#include <soc/bcm2835/raspberrypi-firmware.h> + +#define UNDERVOLTAGE_STICKY_BIT BIT(16) + +struct rpi_hwmon_data { + struct device *hwmon_dev; + struct rpi_firmware *fw; + u32 last_throttled; + struct delayed_work get_values_poll_work; +}; + +static void rpi_firmware_get_throttled(struct rpi_hwmon_data *data) +{ + u32 new_uv, old_uv, value; + int ret; + + /* Clear sticky bits */ + value = 0xffff; + + ret = rpi_firmware_property(data->fw, RPI_FIRMWARE_GET_THROTTLED, + &value, sizeof(value)); + if (ret) { + dev_err_once(data->hwmon_dev, "%s: Failed to get throttled (%d)\n", + __func__, ret); + return; + } + + new_uv = value & UNDERVOLTAGE_STICKY_BIT; + old_uv = data->last_throttled & UNDERVOLTAGE_STICKY_BIT; + data->last_throttled = value; + + if (new_uv == old_uv) + return; + + if (new_uv) + dev_crit(data->hwmon_dev, "Under-voltage detected! (0x%08x)\n", + value); + else + dev_info(data->hwmon_dev, "Voltage normalised (0x%08x)\n", + value); + + sysfs_notify(&data->hwmon_dev->kobj, NULL, "in0_lcrit_alarm"); +} + +static void get_values_poll(struct work_struct *work) +{ + struct rpi_hwmon_data *data; + + data = container_of(work, struct rpi_hwmon_data, + get_values_poll_work.work); + + rpi_firmware_get_throttled(data); + + /* + * We can't run faster than the sticky shift (100ms) since we get + * flipping in the sticky bits that are cleared. + */ + schedule_delayed_work(&data->get_values_poll_work, 2 * HZ); +} + +static int rpi_read(struct device *dev, enum hwmon_sensor_types type, + u32 attr, int channel, long *val) +{ + struct rpi_hwmon_data *data = dev_get_drvdata(dev); + + if (type != hwmon_in) + return -EOPNOTSUPP; + + if (attr != hwmon_in_lcrit_alarm) + return -EOPNOTSUPP; + + if (channel) + return -EOPNOTSUPP; + + *val = !!(data->last_throttled & UNDERVOLTAGE_STICKY_BIT); + return 0; +} + +static umode_t rpi_is_visible(const void *_data, enum hwmon_sensor_types type, + u32 attr, int channel) +{ + if (type != hwmon_in) + return 0; + + if (attr != hwmon_in_lcrit_alarm) + return 0; + + if (channel) + return 0; + + return 0444; +} + +static const u32 rpi_in_config[] = { + HWMON_I_LCRIT_ALARM, + 0 +}; + +static const struct hwmon_channel_info rpi_in = { + .type = hwmon_in, + .config = rpi_in_config, +}; + +static const struct hwmon_channel_info *rpi_info[] = { + &rpi_in, + NULL +}; + +static const struct hwmon_ops rpi_hwmon_ops = { + .is_visible = rpi_is_visible, + .read = rpi_read, +}; + +static const struct hwmon_chip_info rpi_chip_info = { + .ops = &rpi_hwmon_ops, + .info = rpi_info, +}; + +static int rpi_hwmon_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct device_node *fw_node; + struct rpi_hwmon_data *data; + int ret; + + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + fw_node = of_get_parent(dev->of_node); + if (!fw_node) { + dev_err(dev, "Missing firmware node\n"); + return -ENOENT; + } + + data->fw = rpi_firmware_get(fw_node); + of_node_put(fw_node); + if (!data->fw) + return -EPROBE_DEFER; + + ret = rpi_firmware_property(data->fw, RPI_FIRMWARE_GET_THROTTLED, + &data->last_throttled, + sizeof(data->last_throttled)); + if (ret) { + dev_info(dev, "Firmware doesn't support GET_THROTTLED\n"); + return -EOPNOTSUPP; + } + + data->hwmon_dev = devm_hwmon_device_register_with_info(dev, "rpi_volt", + data, + &rpi_chip_info, + NULL); + + INIT_DELAYED_WORK(&data->get_values_poll_work, get_values_poll); + platform_set_drvdata(pdev, data); + + if (!PTR_ERR_OR_ZERO(data->hwmon_dev)) + schedule_delayed_work(&data->get_values_poll_work, 2 * HZ); + + return PTR_ERR_OR_ZERO(data->hwmon_dev); +} + +static int rpi_hwmon_remove(struct platform_device *pdev) +{ + struct rpi_hwmon_data *data = platform_get_drvdata(pdev); + + cancel_delayed_work_sync(&data->get_values_poll_work); + + return 0; +} + +static const struct of_device_id rpi_hwmon_of_match[] = { + { .compatible = "raspberrypi,bcm2835-hwmon", }, + { /* sentinel */}, +}; +MODULE_DEVICE_TABLE(of, rpi_hwmon_of_match); + +static struct platform_driver rpi_hwmon_driver = { + .probe = rpi_hwmon_probe, + .remove = rpi_hwmon_remove, + .driver = { + .name = "raspberrypi-hwmon", + .of_match_table = rpi_hwmon_of_match, + }, +}; +module_platform_driver(rpi_hwmon_driver); + +MODULE_AUTHOR("Stefan Wahren <stefan.wahren@i2se.com>"); +MODULE_DESCRIPTION("Raspberry Pi voltage sensor driver"); +MODULE_LICENSE("GPL v2");
Currently there is no easy way to detect under-voltage conditions on a remote Raspberry Pi. This hwmon driver retrieves the state of the under-voltage sensor via mailbox interface. The handling based on Noralf's modifications to the downstream firmware driver. In case of an under-voltage condition only an entry is written to the kernel log. CC: "Noralf Trønnes" <noralf@tronnes.org> Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com> --- drivers/hwmon/Kconfig | 10 ++ drivers/hwmon/Makefile | 1 + drivers/hwmon/raspberrypi-hwmon.c | 207 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 218 insertions(+) create mode 100644 drivers/hwmon/raspberrypi-hwmon.c