| Message ID | cover.1510520397.git.hns@goldelico.com |
|---|---|
| Headers | show |
| Series | misc: new serdev based drivers for Wi2Wi w2sg00x4 GPS module | expand |
On Sun, Nov 12, 2017 at 09:59:56PM +0100, H. Nikolaus Schaller wrote: > Add driver for Wi2Wi W2SG0004/84 GPS module connected through uart. > > Use serdev API hooks to monitor and forward the UART traffic to /dev/GPSn > and turn on/off the module. It also detects if the module is turned on (sends data) > but should be off, e.g. if it was already turned on during boot or power-on-reset. > > Additionally, rfkill block/unblock can be used to control an external LNA > (and power down the module if not needed). > > The driver concept is based on code developed by NeilBrown <neilb@suse.de> > but simplified and adapted to use the new serdev API introduced in 4.11. > > Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com> > --- > drivers/misc/Kconfig | 10 + > drivers/misc/Makefile | 1 + > drivers/misc/w2sg0004.c | 565 +++++++++++++++++++++++++++++++++++++++++++++++ > include/linux/w2sg0004.h | 27 +++ > 4 files changed, 603 insertions(+) > create mode 100644 drivers/misc/w2sg0004.c > create mode 100644 include/linux/w2sg0004.h > > diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig > index 8136dc7e863d..09d171d68408 100644 > --- a/drivers/misc/Kconfig > +++ b/drivers/misc/Kconfig > @@ -518,4 +518,14 @@ source "drivers/misc/mic/Kconfig" > source "drivers/misc/genwqe/Kconfig" > source "drivers/misc/echo/Kconfig" > source "drivers/misc/cxl/Kconfig" > + > +config W2SG0004 > + tristate "W2SG00x4 on/off control" > + depends on GPIOLIB && SERIAL_DEV_BUS > + help > + Enable on/off control of W2SG00x4 GPS moduled connected > + to some SoC UART to allow powering up/down if the /dev/ttyGPSn > + is opened/closed. > + It also provides a rfkill gps name to control the LNA power. > + > endmenu > diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile > index ad0e64fdba34..abcb667e0ff0 100644 > --- a/drivers/misc/Makefile > +++ b/drivers/misc/Makefile > @@ -51,6 +51,7 @@ obj-$(CONFIG_SRAM_EXEC) += sram-exec.o > obj-y += mic/ > obj-$(CONFIG_GENWQE) += genwqe/ > obj-$(CONFIG_ECHO) += echo/ > +obj-$(CONFIG_W2SG0004) += w2sg0004.o > obj-$(CONFIG_VEXPRESS_SYSCFG) += vexpress-syscfg.o > obj-$(CONFIG_CXL_BASE) += cxl/ > obj-$(CONFIG_ASPEED_LPC_CTRL) += aspeed-lpc-ctrl.o > diff --git a/drivers/misc/w2sg0004.c b/drivers/misc/w2sg0004.c > new file mode 100644 > index 000000000000..55101aa6beeb > --- /dev/null > +++ b/drivers/misc/w2sg0004.c > @@ -0,0 +1,565 @@ > +/* > + * w2sg0004.c Listing the filename is pointless IMO. You need a license too. Use SPDX tag (on first line with C++ style comment). > + * Driver for power controlling the w2sg0004/w2sg0084 GPS receiver. > + * > + * This receiver has an ON/OFF pin which must be toggled to > + * turn the device 'on' of 'off'. A high->low->high toggle > + * will switch the device on if it is off, and off if it is on. > + * > + * To enable receiving on/off requests we register with the > + * UART power management notifications. > + * > + * It is not possible to directly detect the state of the device. > + * However when it is on it will send characters on a UART line > + * regularly. > + * > + * To detect that the power state is out of sync (e.g. if GPS > + * was enabled before a reboot), we register for UART data received > + * notifications. > + * > + * In addition we register as a rfkill client so that we can > + * control the LNA power. > + * > + */ > + > +#include <linux/delay.h> > +#include <linux/err.h> > +#include <linux/interrupt.h> > +#include <linux/irq.h> > +#include <linux/module.h> > +#include <linux/of.h> > +#include <linux/of_irq.h> > +#include <linux/of_gpio.h> > +#include <linux/platform_device.h> > +#include <linux/rfkill.h> > +#include <linux/serdev.h> > +#include <linux/sched.h> > +#include <linux/slab.h> > +#include <linux/tty.h> > +#include <linux/tty_flip.h> > +#include <linux/w2sg0004.h> > +#include <linux/workqueue.h> > + > +/* > + * There seems to be restrictions on how quickly we can toggle the > + * on/off line. data sheets says "two rtc ticks", whatever that means. > + * If we do it too soon it doesn't work. > + * So we have a state machine which uses the common work queue to ensure > + * clean transitions. > + * When a change is requested we record that request and only act on it > + * once the previous change has completed. > + * A change involves a 10ms low pulse, and a 990ms raised level, so only > + * one change per second. > + */ > + > +enum w2sg_state { > + W2SG_IDLE, /* is not changing state */ > + W2SG_PULSE, /* activate on/off impulse */ > + W2SG_NOPULSE /* deactivate on/off impulse */ > +}; > + > +struct w2sg_data { > + struct rfkill *rf_kill; > + struct regulator *lna_regulator; > + int lna_blocked; /* rfkill block gps active */ > + int lna_is_off; /* LNA is currently off */ > + int is_on; /* current state (0/1) */ > + unsigned long last_toggle; > + unsigned long backoff; /* time to wait since last_toggle */ > + int on_off_gpio; /* the on-off gpio number */ > + struct serdev_device *uart; /* uart connected to the chip */ > + struct tty_driver *tty_drv; /* this is the user space tty */ > + struct device *dev; /* from tty_port_register_device() */ > + struct tty_port port; > + int open_count; /* how often we were opened */ > + enum w2sg_state state; > + int requested; /* requested state (0/1) */ > + int suspended; > + struct delayed_work work; > + int discard_count; > +}; > + > +static struct w2sg_data *w2sg_by_minor[1]; > + > +static int w2sg_set_lna_power(struct w2sg_data *data) > +{ > + int ret = 0; > + int off = data->suspended || !data->requested || data->lna_blocked; > + > + pr_debug("%s: %s\n", __func__, off ? "off" : "on"); > + > + if (off != data->lna_is_off) { > + data->lna_is_off = off; > + if (!IS_ERR_OR_NULL(data->lna_regulator)) { > + if (off) > + regulator_disable(data->lna_regulator); > + else > + ret = regulator_enable(data->lna_regulator); > + } > + } > + > + return ret; > +} > + > +static void w2sg_set_power(void *pdata, int val) > +{ > + struct w2sg_data *data = (struct w2sg_data *) pdata; > + > + pr_debug("%s to state=%d (requested=%d)\n", __func__, val, data->requested); > + > + if (val && !data->requested) { > + data->requested = true; > + } else if (!val && data->requested) { > + data->backoff = HZ; > + data->requested = false; > + } else > + return; > + > + pr_debug("w2sg00x4 scheduled for %d\n", data->requested); > + > + if (!data->suspended) > + schedule_delayed_work(&data->work, 0); > +} > + > +/* called each time data is received by the UART (i.e. sent by the w2sg0004) */ > + > +static int w2sg_uart_receive_buf(struct serdev_device *serdev, > + const unsigned char *rxdata, > + size_t count) > +{ > + struct w2sg_data *data = > + (struct w2sg_data *) serdev_device_get_drvdata(serdev); > + > + if (!data->requested && !data->is_on) { > + /* > + * we have received characters while the w2sg > + * should have been be turned off > + */ > + data->discard_count += count; > + if ((data->state == W2SG_IDLE) && > + time_after(jiffies, > + data->last_toggle + data->backoff)) { > + /* Should be off by now, time to toggle again */ > + pr_debug("w2sg00x4 has sent %d characters data although it should be off!\n", > + data->discard_count); > + > + data->discard_count = 0; > + > + data->is_on = true; > + data->backoff *= 2; > + if (!data->suspended) > + schedule_delayed_work(&data->work, 0); > + } > + } else if (data->open_count > 0) { > + int n; > + > + pr_debug("w2sg00x4: push %d chars to tty port\n", count); > + > + /* pass to user-space */ > + n = tty_insert_flip_string(&data->port, rxdata, count); > + if (n != count) > + pr_err("w2sg00x4: did loose %d characters\n", count - n); > + tty_flip_buffer_push(&data->port); > + return n; > + } > + > + /* assume we have processed everything */ > + return count; > +} > + > +/* try to toggle the power state by sending a pulse to the on-off GPIO */ > + > +static void toggle_work(struct work_struct *work) > +{ > + struct w2sg_data *data = container_of(work, struct w2sg_data, > + work.work); > + > + switch (data->state) { > + case W2SG_IDLE: > + if (data->requested == data->is_on) > + return; > + > + w2sg_set_lna_power(data); /* update LNA power state */ > + gpio_set_value_cansleep(data->on_off_gpio, 0); > + data->state = W2SG_PULSE; > + > + pr_debug("w2sg: power gpio ON\n"); > + > + schedule_delayed_work(&data->work, > + msecs_to_jiffies(10)); > + break; > + > + case W2SG_PULSE: > + gpio_set_value_cansleep(data->on_off_gpio, 1); > + data->last_toggle = jiffies; > + data->state = W2SG_NOPULSE; > + data->is_on = !data->is_on; > + > + pr_debug("w2sg: power gpio OFF\n"); > + > + schedule_delayed_work(&data->work, > + msecs_to_jiffies(10)); > + break; > + > + case W2SG_NOPULSE: > + data->state = W2SG_IDLE; > + > + pr_debug("w2sg: idle\n"); > + > + break; > + > + } > +} > + > +static int w2sg_rfkill_set_block(void *pdata, bool blocked) > +{ > + struct w2sg_data *data = pdata; > + > + pr_debug("%s: blocked: %d\n", __func__, blocked); > + > + data->lna_blocked = blocked; > + > + return w2sg_set_lna_power(data); > +} > + > +static struct rfkill_ops w2sg0004_rfkill_ops = { > + .set_block = w2sg_rfkill_set_block, > +}; > + > +static struct serdev_device_ops serdev_ops = { > + .receive_buf = w2sg_uart_receive_buf, > +}; > + > +/* > + * we are a man-in the middle between the user-space visible tty port > + * and the serdev tty where the chip is connected. > + * This allows us to recognise when the device should be powered on > + * or off and handle the "false" state that data arrives while no > + * users-space tty client exists. > + */ > + > +static struct w2sg_data *w2sg_get_by_minor(unsigned int minor) > +{ > + return w2sg_by_minor[minor]; > +} > + > +static int w2sg_tty_install(struct tty_driver *driver, struct tty_struct *tty) > +{ > + struct w2sg_data *data; > + int retval; > + > + pr_debug("%s() tty = %p\n", __func__, tty); > + > + data = w2sg_get_by_minor(tty->index); > + > + if (!data) > + return -ENODEV; > + > + retval = tty_standard_install(driver, tty); > + if (retval) > + goto error_init_termios; > + > + tty->driver_data = data; > + > + return 0; > + > +error_init_termios: > + tty_port_put(&data->port); > + return retval; > +} > + > +static int w2sg_tty_open(struct tty_struct *tty, struct file *file) > +{ > + struct w2sg_data *data = tty->driver_data; > + > + pr_debug("%s() data = %p open_count = ++%d\n", __func__, data, data->open_count); > + > + w2sg_set_power(data, ++data->open_count > 0); > + > + return tty_port_open(&data->port, tty, file); > +} > + > +static void w2sg_tty_close(struct tty_struct *tty, struct file *file) > +{ > + struct w2sg_data *data = tty->driver_data; > + > + pr_debug("%s()\n", __func__); > + > + w2sg_set_power(data, --data->open_count > 0); > + > + tty_port_close(&data->port, tty, file); > +} > + > +static int w2sg_tty_write(struct tty_struct *tty, > + const unsigned char *buffer, int count) > +{ > + struct w2sg_data *data = tty->driver_data; > + > + /* simply pass down to UART */ > + return serdev_device_write_buf(data->uart, buffer, count); > +} > + > + > +static const struct tty_operations w2sg_serial_ops = { > + .install = w2sg_tty_install, > + .open = w2sg_tty_open, > + .close = w2sg_tty_close, > + .write = w2sg_tty_write, > +}; > + > +static const struct tty_port_operations w2sg_port_ops = { > +}; > + > +static int w2sg_probe(struct serdev_device *serdev) > +{ > + struct w2sg_pdata *pdata = NULL; > + struct w2sg_data *data; > + struct rfkill *rf_kill; > + int err; > + int minor; > + > + pr_debug("%s()\n", __func__); > + > + minor = 0; > + if (w2sg_by_minor[minor]) { > + pr_err("w2sg minor is already in use!\n"); > + return -ENODEV; > + } > + > + if (serdev->dev.of_node) { > + struct device *dev = &serdev->dev; > + enum of_gpio_flags flags; > + > + pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL); > + if (!pdata) > + return -ENOMEM; > + > + pdata->on_off_gpio = of_get_named_gpio_flags(dev->of_node, > + "enable-gpios", 0, > + &flags); > + > + /* defer until we have all gpios */ > + if (pdata->on_off_gpio == -EPROBE_DEFER) > + return -EPROBE_DEFER; > + > + pdata->lna_regulator = devm_regulator_get_optional(dev, "lna"); > + if (IS_ERR(pdata->lna_regulator)) { > + /* defer until we can get the regulator */ > + if (PTR_ERR(pdata->lna_regulator) == -EPROBE_DEFER) > + return -EPROBE_DEFER; > + > + pdata->lna_regulator = NULL; > + } > + > + pr_debug("%s() lna_regulator = %p\n", __func__, > + pdata->lna_regulator); > + > + serdev->dev.platform_data = pdata; > + } > + > + data = devm_kzalloc(&serdev->dev, sizeof(*data), GFP_KERNEL); > + if (data == NULL) > + return -ENOMEM; > + > + w2sg_by_minor[minor] = data; > + > + serdev_device_set_drvdata(serdev, data); > + > + data->lna_regulator = pdata->lna_regulator; NULL ptr dereference if you have no of_node. > + data->lna_blocked = true; > + data->lna_is_off = true; > + > + data->on_off_gpio = pdata->on_off_gpio; > + > + data->is_on = false; > + data->requested = false; > + data->state = W2SG_IDLE; > + data->last_toggle = jiffies; > + data->backoff = HZ; > + > + data->uart = serdev; > + > + INIT_DELAYED_WORK(&data->work, toggle_work); > + > + err = devm_gpio_request(&serdev->dev, data->on_off_gpio, > + "w2sg0004-on-off"); > + if (err < 0) > + goto out; > + > + gpio_direction_output(data->on_off_gpio, false); > + > + serdev_device_set_client_ops(data->uart, &serdev_ops); > + serdev_device_open(data->uart); > + > + serdev_device_set_baudrate(data->uart, 9600); > + serdev_device_set_flow_control(data->uart, false); > + > + rf_kill = rfkill_alloc("GPS", &serdev->dev, RFKILL_TYPE_GPS, > + &w2sg0004_rfkill_ops, data); > + if (rf_kill == NULL) { > + err = -ENOMEM; > + goto err_rfkill; > + } > + > + err = rfkill_register(rf_kill); > + if (err) { > + dev_err(&serdev->dev, "Cannot register rfkill device\n"); > + goto err_rfkill; > + } > + > + data->rf_kill = rf_kill; > + > + /* allocate the tty driver */ > + data->tty_drv = alloc_tty_driver(1); Is there an advantage or reason to make this a tty driver rather than just a char driver? Perhaps this should be under drivers/tty if it is a tty driver. > + if (!data->tty_drv) > + return -ENOMEM; > + > + /* initialize the tty driver */ > + data->tty_drv->owner = THIS_MODULE; > + data->tty_drv->driver_name = "w2sg0004"; > + data->tty_drv->name = "ttyGPS"; > + data->tty_drv->major = 0; > + data->tty_drv->minor_start = 0; > + data->tty_drv->type = TTY_DRIVER_TYPE_SERIAL; > + data->tty_drv->subtype = SERIAL_TYPE_NORMAL; > + data->tty_drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV; > + data->tty_drv->init_termios = tty_std_termios; > + data->tty_drv->init_termios.c_cflag = B9600 | CS8 | CREAD | > + HUPCL | CLOCAL; > + /* > + * optional: > + * tty_termios_encode_baud_rate(&data->tty_drv->init_termios, > + 115200, 115200); > + * w2sg_tty_termios(&data->tty_drv->init_termios); > + */ > + tty_set_operations(data->tty_drv, &w2sg_serial_ops); > + > + /* register the tty driver */ > + err = tty_register_driver(data->tty_drv); > + if (err) { > + pr_err("%s - tty_register_driver failed(%d)\n", > + __func__, err); > + put_tty_driver(data->tty_drv); > + goto err_rfkill; > + } > + > + tty_port_init(&data->port); > + data->port.ops = &w2sg_port_ops; > + > +/* > + * FIXME: this appears to reenter this probe() function a second time > + * which only fails because the gpio is already assigned > + */ > + > + data->dev = tty_port_register_device(&data->port, > + data->tty_drv, minor, &serdev->dev); > + > + pr_debug("w2sg probed\n"); > + > + /* keep off until user space requests the device */ > + w2sg_set_power(data, false); > + > + return 0; > + > +err_rfkill: > + rfkill_destroy(rf_kill); > + serdev_device_close(data->uart); > +out: > + return err; > +} > + > +static void w2sg_remove(struct serdev_device *serdev) > +{ > + struct w2sg_data *data = serdev_device_get_drvdata(serdev); > + int minor; > + > + cancel_delayed_work_sync(&data->work); > + > + /* what is the right sequence to avoid problems? */ > + serdev_device_close(data->uart); > + > + minor = 0; > + tty_unregister_device(data->tty_drv, minor); > + > + tty_unregister_driver(data->tty_drv); > +} > + > +static int w2sg_suspend(struct device *dev) > +{ > + struct w2sg_data *data = dev_get_drvdata(dev); > + > + data->suspended = true; > + > + cancel_delayed_work_sync(&data->work); > + > + w2sg_set_lna_power(data); /* shuts down if needed */ > + > + if (data->state == W2SG_PULSE) { > + msleep(10); > + gpio_set_value_cansleep(data->on_off_gpio, 1); > + data->last_toggle = jiffies; > + data->is_on = !data->is_on; > + data->state = W2SG_NOPULSE; > + } > + > + if (data->state == W2SG_NOPULSE) { > + msleep(10); > + data->state = W2SG_IDLE; > + } > + > + if (data->is_on) { > + pr_info("GPS off for suspend %d %d %d\n", data->requested, > + data->is_on, data->lna_is_off); > + > + gpio_set_value_cansleep(data->on_off_gpio, 0); > + msleep(10); > + gpio_set_value_cansleep(data->on_off_gpio, 1); > + data->is_on = 0; > + } > + > + return 0; > +} > + > +static int w2sg_resume(struct device *dev) > +{ > + struct w2sg_data *data = dev_get_drvdata(dev); > + > + data->suspended = false; > + > + pr_info("GPS resuming %d %d %d\n", data->requested, > + data->is_on, data->lna_is_off); > + > + schedule_delayed_work(&data->work, 0); /* enables LNA if needed */ > + > + return 0; > +} > + > +#if defined(CONFIG_OF) > +static const struct of_device_id w2sg0004_of_match[] = { > + { .compatible = "wi2wi,w2sg0004" }, > + { .compatible = "wi2wi,w2sg0084" }, > + {}, > +}; > +MODULE_DEVICE_TABLE(of, w2sg0004_of_match); > +#endif > + > +SIMPLE_DEV_PM_OPS(w2sg_pm_ops, w2sg_suspend, w2sg_resume); > + > +static struct serdev_device_driver w2sg_driver = { > + .probe = w2sg_probe, > + .remove = w2sg_remove, > + .driver = { > + .name = "w2sg0004", > + .owner = THIS_MODULE, > + .pm = &w2sg_pm_ops, > + .of_match_table = of_match_ptr(w2sg0004_of_match) > + }, > +}; > + > +module_serdev_device_driver(w2sg_driver); > + > +MODULE_ALIAS("w2sg0004"); > + > +MODULE_AUTHOR("NeilBrown <neilb@suse.de>"); > +MODULE_DESCRIPTION("w2sg0004 GPS power management driver"); > +MODULE_LICENSE("GPL v2"); > diff --git a/include/linux/w2sg0004.h b/include/linux/w2sg0004.h > new file mode 100644 > index 000000000000..ad0c4a18e01d > --- /dev/null > +++ b/include/linux/w2sg0004.h > @@ -0,0 +1,27 @@ > +/* > + * UART slave to allow ON/OFF control of w2sg0004 GPS receiver. > + * > + * Copyright (C) 2011 Neil Brown <neil@brown.name> > + * > + * This program is free software; you can redistribute it and/or > + * modify it under the terms of the GNU General Public License > + * version 2 as published by the Free Software Foundation. > + * > + * This program is distributed in the hope that it will be useful, but > + * WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > + * General Public License for more details. > + */ > + > + > + > +#ifndef __LINUX_W2SG0004_H > +#define __LINUX_W2SG0004_H > + > +#include <linux/regulator/consumer.h> > + > +struct w2sg_pdata { You don't really support platform_data, so you can move this into the driver. > + struct regulator *lna_regulator; /* enable LNA power */ > + int on_off_gpio; /* on-off input of the GPS module */ > +}; > +#endif /* __LINUX_W2SG0004_H */ > -- > 2.12.2 > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Rob, > Am 15.11.2017 um 21:17 schrieb Rob Herring <robh@kernel.org>: > > On Sun, Nov 12, 2017 at 09:59:56PM +0100, H. Nikolaus Schaller wrote: >> Add driver for Wi2Wi W2SG0004/84 GPS module connected through uart. >> >> Use serdev API hooks to monitor and forward the UART traffic to /dev/GPSn >> and turn on/off the module. It also detects if the module is turned on (sends data) >> but should be off, e.g. if it was already turned on during boot or power-on-reset. >> >> Additionally, rfkill block/unblock can be used to control an external LNA >> (and power down the module if not needed). >> >> The driver concept is based on code developed by NeilBrown <neilb@suse.de> >> but simplified and adapted to use the new serdev API introduced in 4.11. >> >> Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com> >> --- >> drivers/misc/Kconfig | 10 + >> drivers/misc/Makefile | 1 + >> drivers/misc/w2sg0004.c | 565 +++++++++++++++++++++++++++++++++++++++++++++++ >> include/linux/w2sg0004.h | 27 +++ >> 4 files changed, 603 insertions(+) >> create mode 100644 drivers/misc/w2sg0004.c >> create mode 100644 include/linux/w2sg0004.h >> >> diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig >> index 8136dc7e863d..09d171d68408 100644 >> --- a/drivers/misc/Kconfig >> +++ b/drivers/misc/Kconfig >> @@ -518,4 +518,14 @@ source "drivers/misc/mic/Kconfig" >> source "drivers/misc/genwqe/Kconfig" >> source "drivers/misc/echo/Kconfig" >> source "drivers/misc/cxl/Kconfig" >> + >> +config W2SG0004 >> + tristate "W2SG00x4 on/off control" >> + depends on GPIOLIB && SERIAL_DEV_BUS >> + help >> + Enable on/off control of W2SG00x4 GPS moduled connected >> + to some SoC UART to allow powering up/down if the /dev/ttyGPSn >> + is opened/closed. >> + It also provides a rfkill gps name to control the LNA power. >> + >> endmenu >> diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile >> index ad0e64fdba34..abcb667e0ff0 100644 >> --- a/drivers/misc/Makefile >> +++ b/drivers/misc/Makefile >> @@ -51,6 +51,7 @@ obj-$(CONFIG_SRAM_EXEC) += sram-exec.o >> obj-y += mic/ >> obj-$(CONFIG_GENWQE) += genwqe/ >> obj-$(CONFIG_ECHO) += echo/ >> +obj-$(CONFIG_W2SG0004) += w2sg0004.o >> obj-$(CONFIG_VEXPRESS_SYSCFG) += vexpress-syscfg.o >> obj-$(CONFIG_CXL_BASE) += cxl/ >> obj-$(CONFIG_ASPEED_LPC_CTRL) += aspeed-lpc-ctrl.o >> diff --git a/drivers/misc/w2sg0004.c b/drivers/misc/w2sg0004.c >> new file mode 100644 >> index 000000000000..55101aa6beeb >> --- /dev/null >> +++ b/drivers/misc/w2sg0004.c >> @@ -0,0 +1,565 @@ >> +/* >> + * w2sg0004.c > > Listing the filename is pointless IMO. Ok. > You need a license too. Use SPDX > tag (on first line with C++ style comment). Well, this is too new to be aware of... Isn't the MODULE_LICENSE enough any more? > >> + * Driver for power controlling the w2sg0004/w2sg0084 GPS receiver. >> + * >> + * This receiver has an ON/OFF pin which must be toggled to >> + * turn the device 'on' of 'off'. A high->low->high toggle >> + * will switch the device on if it is off, and off if it is on. >> + * >> + * To enable receiving on/off requests we register with the >> + * UART power management notifications. >> + * >> + * It is not possible to directly detect the state of the device. >> + * However when it is on it will send characters on a UART line >> + * regularly. >> + * >> + * To detect that the power state is out of sync (e.g. if GPS >> + * was enabled before a reboot), we register for UART data received >> + * notifications. >> + * >> + * In addition we register as a rfkill client so that we can >> + * control the LNA power. >> + * >> + */ >> + >> +#include <linux/delay.h> >> +#include <linux/err.h> >> +#include <linux/interrupt.h> >> +#include <linux/irq.h> >> +#include <linux/module.h> >> +#include <linux/of.h> >> +#include <linux/of_irq.h> >> +#include <linux/of_gpio.h> >> +#include <linux/platform_device.h> >> +#include <linux/rfkill.h> >> +#include <linux/serdev.h> >> +#include <linux/sched.h> >> +#include <linux/slab.h> >> +#include <linux/tty.h> >> +#include <linux/tty_flip.h> >> +#include <linux/w2sg0004.h> >> +#include <linux/workqueue.h> >> + >> +/* >> + * There seems to be restrictions on how quickly we can toggle the >> + * on/off line. data sheets says "two rtc ticks", whatever that means. >> + * If we do it too soon it doesn't work. >> + * So we have a state machine which uses the common work queue to ensure >> + * clean transitions. >> + * When a change is requested we record that request and only act on it >> + * once the previous change has completed. >> + * A change involves a 10ms low pulse, and a 990ms raised level, so only >> + * one change per second. >> + */ >> + >> +enum w2sg_state { >> + W2SG_IDLE, /* is not changing state */ >> + W2SG_PULSE, /* activate on/off impulse */ >> + W2SG_NOPULSE /* deactivate on/off impulse */ >> +}; >> + >> +struct w2sg_data { >> + struct rfkill *rf_kill; >> + struct regulator *lna_regulator; >> + int lna_blocked; /* rfkill block gps active */ >> + int lna_is_off; /* LNA is currently off */ >> + int is_on; /* current state (0/1) */ >> + unsigned long last_toggle; >> + unsigned long backoff; /* time to wait since last_toggle */ >> + int on_off_gpio; /* the on-off gpio number */ >> + struct serdev_device *uart; /* uart connected to the chip */ >> + struct tty_driver *tty_drv; /* this is the user space tty */ >> + struct device *dev; /* from tty_port_register_device() */ >> + struct tty_port port; >> + int open_count; /* how often we were opened */ >> + enum w2sg_state state; >> + int requested; /* requested state (0/1) */ >> + int suspended; >> + struct delayed_work work; >> + int discard_count; >> +}; >> + >> +static struct w2sg_data *w2sg_by_minor[1]; >> + >> +static int w2sg_set_lna_power(struct w2sg_data *data) >> +{ >> + int ret = 0; >> + int off = data->suspended || !data->requested || data->lna_blocked; >> + >> + pr_debug("%s: %s\n", __func__, off ? "off" : "on"); >> + >> + if (off != data->lna_is_off) { >> + data->lna_is_off = off; >> + if (!IS_ERR_OR_NULL(data->lna_regulator)) { >> + if (off) >> + regulator_disable(data->lna_regulator); >> + else >> + ret = regulator_enable(data->lna_regulator); >> + } >> + } >> + >> + return ret; >> +} >> + >> +static void w2sg_set_power(void *pdata, int val) >> +{ >> + struct w2sg_data *data = (struct w2sg_data *) pdata; >> + >> + pr_debug("%s to state=%d (requested=%d)\n", __func__, val, data->requested); >> + >> + if (val && !data->requested) { >> + data->requested = true; >> + } else if (!val && data->requested) { >> + data->backoff = HZ; >> + data->requested = false; >> + } else >> + return; >> + >> + pr_debug("w2sg00x4 scheduled for %d\n", data->requested); >> + >> + if (!data->suspended) >> + schedule_delayed_work(&data->work, 0); >> +} >> + >> +/* called each time data is received by the UART (i.e. sent by the w2sg0004) */ >> + >> +static int w2sg_uart_receive_buf(struct serdev_device *serdev, >> + const unsigned char *rxdata, >> + size_t count) >> +{ >> + struct w2sg_data *data = >> + (struct w2sg_data *) serdev_device_get_drvdata(serdev); >> + >> + if (!data->requested && !data->is_on) { >> + /* >> + * we have received characters while the w2sg >> + * should have been be turned off >> + */ >> + data->discard_count += count; >> + if ((data->state == W2SG_IDLE) && >> + time_after(jiffies, >> + data->last_toggle + data->backoff)) { >> + /* Should be off by now, time to toggle again */ >> + pr_debug("w2sg00x4 has sent %d characters data although it should be off!\n", >> + data->discard_count); >> + >> + data->discard_count = 0; >> + >> + data->is_on = true; >> + data->backoff *= 2; >> + if (!data->suspended) >> + schedule_delayed_work(&data->work, 0); >> + } >> + } else if (data->open_count > 0) { >> + int n; >> + >> + pr_debug("w2sg00x4: push %d chars to tty port\n", count); >> + >> + /* pass to user-space */ >> + n = tty_insert_flip_string(&data->port, rxdata, count); >> + if (n != count) >> + pr_err("w2sg00x4: did loose %d characters\n", count - n); >> + tty_flip_buffer_push(&data->port); >> + return n; >> + } >> + >> + /* assume we have processed everything */ >> + return count; >> +} >> + >> +/* try to toggle the power state by sending a pulse to the on-off GPIO */ >> + >> +static void toggle_work(struct work_struct *work) >> +{ >> + struct w2sg_data *data = container_of(work, struct w2sg_data, >> + work.work); >> + >> + switch (data->state) { >> + case W2SG_IDLE: >> + if (data->requested == data->is_on) >> + return; >> + >> + w2sg_set_lna_power(data); /* update LNA power state */ >> + gpio_set_value_cansleep(data->on_off_gpio, 0); >> + data->state = W2SG_PULSE; >> + >> + pr_debug("w2sg: power gpio ON\n"); >> + >> + schedule_delayed_work(&data->work, >> + msecs_to_jiffies(10)); >> + break; >> + >> + case W2SG_PULSE: >> + gpio_set_value_cansleep(data->on_off_gpio, 1); >> + data->last_toggle = jiffies; >> + data->state = W2SG_NOPULSE; >> + data->is_on = !data->is_on; >> + >> + pr_debug("w2sg: power gpio OFF\n"); >> + >> + schedule_delayed_work(&data->work, >> + msecs_to_jiffies(10)); >> + break; >> + >> + case W2SG_NOPULSE: >> + data->state = W2SG_IDLE; >> + >> + pr_debug("w2sg: idle\n"); >> + >> + break; >> + >> + } >> +} >> + >> +static int w2sg_rfkill_set_block(void *pdata, bool blocked) >> +{ >> + struct w2sg_data *data = pdata; >> + >> + pr_debug("%s: blocked: %d\n", __func__, blocked); >> + >> + data->lna_blocked = blocked; >> + >> + return w2sg_set_lna_power(data); >> +} >> + >> +static struct rfkill_ops w2sg0004_rfkill_ops = { >> + .set_block = w2sg_rfkill_set_block, >> +}; >> + >> +static struct serdev_device_ops serdev_ops = { >> + .receive_buf = w2sg_uart_receive_buf, >> +}; >> + >> +/* >> + * we are a man-in the middle between the user-space visible tty port >> + * and the serdev tty where the chip is connected. >> + * This allows us to recognise when the device should be powered on >> + * or off and handle the "false" state that data arrives while no >> + * users-space tty client exists. >> + */ >> + >> +static struct w2sg_data *w2sg_get_by_minor(unsigned int minor) >> +{ >> + return w2sg_by_minor[minor]; >> +} >> + >> +static int w2sg_tty_install(struct tty_driver *driver, struct tty_struct *tty) >> +{ >> + struct w2sg_data *data; >> + int retval; >> + >> + pr_debug("%s() tty = %p\n", __func__, tty); >> + >> + data = w2sg_get_by_minor(tty->index); >> + >> + if (!data) >> + return -ENODEV; >> + >> + retval = tty_standard_install(driver, tty); >> + if (retval) >> + goto error_init_termios; >> + >> + tty->driver_data = data; >> + >> + return 0; >> + >> +error_init_termios: >> + tty_port_put(&data->port); >> + return retval; >> +} >> + >> +static int w2sg_tty_open(struct tty_struct *tty, struct file *file) >> +{ >> + struct w2sg_data *data = tty->driver_data; >> + >> + pr_debug("%s() data = %p open_count = ++%d\n", __func__, data, data->open_count); >> + >> + w2sg_set_power(data, ++data->open_count > 0); >> + >> + return tty_port_open(&data->port, tty, file); >> +} >> + >> +static void w2sg_tty_close(struct tty_struct *tty, struct file *file) >> +{ >> + struct w2sg_data *data = tty->driver_data; >> + >> + pr_debug("%s()\n", __func__); >> + >> + w2sg_set_power(data, --data->open_count > 0); >> + >> + tty_port_close(&data->port, tty, file); >> +} >> + >> +static int w2sg_tty_write(struct tty_struct *tty, >> + const unsigned char *buffer, int count) >> +{ >> + struct w2sg_data *data = tty->driver_data; >> + >> + /* simply pass down to UART */ >> + return serdev_device_write_buf(data->uart, buffer, count); >> +} >> + >> + >> +static const struct tty_operations w2sg_serial_ops = { >> + .install = w2sg_tty_install, >> + .open = w2sg_tty_open, >> + .close = w2sg_tty_close, >> + .write = w2sg_tty_write, >> +}; >> + >> +static const struct tty_port_operations w2sg_port_ops = { >> +}; >> + >> +static int w2sg_probe(struct serdev_device *serdev) >> +{ >> + struct w2sg_pdata *pdata = NULL; >> + struct w2sg_data *data; >> + struct rfkill *rf_kill; >> + int err; >> + int minor; >> + >> + pr_debug("%s()\n", __func__); >> + >> + minor = 0; >> + if (w2sg_by_minor[minor]) { >> + pr_err("w2sg minor is already in use!\n"); >> + return -ENODEV; >> + } >> + >> + if (serdev->dev.of_node) { >> + struct device *dev = &serdev->dev; >> + enum of_gpio_flags flags; >> + >> + pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL); >> + if (!pdata) >> + return -ENOMEM; >> + >> + pdata->on_off_gpio = of_get_named_gpio_flags(dev->of_node, >> + "enable-gpios", 0, >> + &flags); >> + >> + /* defer until we have all gpios */ >> + if (pdata->on_off_gpio == -EPROBE_DEFER) >> + return -EPROBE_DEFER; >> + >> + pdata->lna_regulator = devm_regulator_get_optional(dev, "lna"); >> + if (IS_ERR(pdata->lna_regulator)) { >> + /* defer until we can get the regulator */ >> + if (PTR_ERR(pdata->lna_regulator) == -EPROBE_DEFER) >> + return -EPROBE_DEFER; >> + >> + pdata->lna_regulator = NULL; >> + } >> + >> + pr_debug("%s() lna_regulator = %p\n", __func__, >> + pdata->lna_regulator); >> + >> + serdev->dev.platform_data = pdata; >> + } >> + >> + data = devm_kzalloc(&serdev->dev, sizeof(*data), GFP_KERNEL); >> + if (data == NULL) >> + return -ENOMEM; >> + >> + w2sg_by_minor[minor] = data; >> + >> + serdev_device_set_drvdata(serdev, data); >> + >> + data->lna_regulator = pdata->lna_regulator; > > NULL ptr dereference if you have no of_node. has more or less already commented by Arnd and will be fixed in PATCH v4. > >> + data->lna_blocked = true; >> + data->lna_is_off = true; >> + >> + data->on_off_gpio = pdata->on_off_gpio; >> + >> + data->is_on = false; >> + data->requested = false; >> + data->state = W2SG_IDLE; >> + data->last_toggle = jiffies; >> + data->backoff = HZ; >> + >> + data->uart = serdev; >> + >> + INIT_DELAYED_WORK(&data->work, toggle_work); >> + >> + err = devm_gpio_request(&serdev->dev, data->on_off_gpio, >> + "w2sg0004-on-off"); >> + if (err < 0) >> + goto out; >> + >> + gpio_direction_output(data->on_off_gpio, false); >> + >> + serdev_device_set_client_ops(data->uart, &serdev_ops); >> + serdev_device_open(data->uart); >> + >> + serdev_device_set_baudrate(data->uart, 9600); >> + serdev_device_set_flow_control(data->uart, false); >> + >> + rf_kill = rfkill_alloc("GPS", &serdev->dev, RFKILL_TYPE_GPS, >> + &w2sg0004_rfkill_ops, data); >> + if (rf_kill == NULL) { >> + err = -ENOMEM; >> + goto err_rfkill; >> + } >> + >> + err = rfkill_register(rf_kill); >> + if (err) { >> + dev_err(&serdev->dev, "Cannot register rfkill device\n"); >> + goto err_rfkill; >> + } >> + >> + data->rf_kill = rf_kill; >> + >> + /* allocate the tty driver */ >> + data->tty_drv = alloc_tty_driver(1); > > Is there an advantage or reason to make this a tty driver rather than > just a char driver? Well, gpsd and other daemons might assume they can tcsetattr or a line discipline etc. > > Perhaps this should be under drivers/tty if it is a tty driver. Well, primarily it is a gps driver... And in some bright future there should be specific gps interfaces (like networking or bluetooth). But there is no drivers/gps and I am not sure if this one should be the first. If you prefer it, it is a simple rename... > >> + if (!data->tty_drv) >> + return -ENOMEM; >> + >> + /* initialize the tty driver */ >> + data->tty_drv->owner = THIS_MODULE; >> + data->tty_drv->driver_name = "w2sg0004"; >> + data->tty_drv->name = "ttyGPS"; >> + data->tty_drv->major = 0; >> + data->tty_drv->minor_start = 0; >> + data->tty_drv->type = TTY_DRIVER_TYPE_SERIAL; >> + data->tty_drv->subtype = SERIAL_TYPE_NORMAL; >> + data->tty_drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV; >> + data->tty_drv->init_termios = tty_std_termios; >> + data->tty_drv->init_termios.c_cflag = B9600 | CS8 | CREAD | >> + HUPCL | CLOCAL; >> + /* >> + * optional: >> + * tty_termios_encode_baud_rate(&data->tty_drv->init_termios, >> + 115200, 115200); >> + * w2sg_tty_termios(&data->tty_drv->init_termios); >> + */ >> + tty_set_operations(data->tty_drv, &w2sg_serial_ops); >> + >> + /* register the tty driver */ >> + err = tty_register_driver(data->tty_drv); >> + if (err) { >> + pr_err("%s - tty_register_driver failed(%d)\n", >> + __func__, err); >> + put_tty_driver(data->tty_drv); >> + goto err_rfkill; >> + } >> + >> + tty_port_init(&data->port); >> + data->port.ops = &w2sg_port_ops; >> + >> +/* >> + * FIXME: this appears to reenter this probe() function a second time >> + * which only fails because the gpio is already assigned >> + */ >> + >> + data->dev = tty_port_register_device(&data->port, >> + data->tty_drv, minor, &serdev->dev); >> + >> + pr_debug("w2sg probed\n"); >> + >> + /* keep off until user space requests the device */ >> + w2sg_set_power(data, false); >> + >> + return 0; >> + >> +err_rfkill: >> + rfkill_destroy(rf_kill); >> + serdev_device_close(data->uart); >> +out: >> + return err; >> +} >> + >> +static void w2sg_remove(struct serdev_device *serdev) >> +{ >> + struct w2sg_data *data = serdev_device_get_drvdata(serdev); >> + int minor; >> + >> + cancel_delayed_work_sync(&data->work); >> + >> + /* what is the right sequence to avoid problems? */ >> + serdev_device_close(data->uart); >> + >> + minor = 0; >> + tty_unregister_device(data->tty_drv, minor); >> + >> + tty_unregister_driver(data->tty_drv); >> +} >> + >> +static int w2sg_suspend(struct device *dev) >> +{ >> + struct w2sg_data *data = dev_get_drvdata(dev); >> + >> + data->suspended = true; >> + >> + cancel_delayed_work_sync(&data->work); >> + >> + w2sg_set_lna_power(data); /* shuts down if needed */ >> + >> + if (data->state == W2SG_PULSE) { >> + msleep(10); >> + gpio_set_value_cansleep(data->on_off_gpio, 1); >> + data->last_toggle = jiffies; >> + data->is_on = !data->is_on; >> + data->state = W2SG_NOPULSE; >> + } >> + >> + if (data->state == W2SG_NOPULSE) { >> + msleep(10); >> + data->state = W2SG_IDLE; >> + } >> + >> + if (data->is_on) { >> + pr_info("GPS off for suspend %d %d %d\n", data->requested, >> + data->is_on, data->lna_is_off); >> + >> + gpio_set_value_cansleep(data->on_off_gpio, 0); >> + msleep(10); >> + gpio_set_value_cansleep(data->on_off_gpio, 1); >> + data->is_on = 0; >> + } >> + >> + return 0; >> +} >> + >> +static int w2sg_resume(struct device *dev) >> +{ >> + struct w2sg_data *data = dev_get_drvdata(dev); >> + >> + data->suspended = false; >> + >> + pr_info("GPS resuming %d %d %d\n", data->requested, >> + data->is_on, data->lna_is_off); >> + >> + schedule_delayed_work(&data->work, 0); /* enables LNA if needed */ >> + >> + return 0; >> +} >> + >> +#if defined(CONFIG_OF) >> +static const struct of_device_id w2sg0004_of_match[] = { >> + { .compatible = "wi2wi,w2sg0004" }, >> + { .compatible = "wi2wi,w2sg0084" }, >> + {}, >> +}; >> +MODULE_DEVICE_TABLE(of, w2sg0004_of_match); >> +#endif >> + >> +SIMPLE_DEV_PM_OPS(w2sg_pm_ops, w2sg_suspend, w2sg_resume); >> + >> +static struct serdev_device_driver w2sg_driver = { >> + .probe = w2sg_probe, >> + .remove = w2sg_remove, >> + .driver = { >> + .name = "w2sg0004", >> + .owner = THIS_MODULE, >> + .pm = &w2sg_pm_ops, >> + .of_match_table = of_match_ptr(w2sg0004_of_match) >> + }, >> +}; >> + >> +module_serdev_device_driver(w2sg_driver); >> + >> +MODULE_ALIAS("w2sg0004"); >> + >> +MODULE_AUTHOR("NeilBrown <neilb@suse.de>"); >> +MODULE_DESCRIPTION("w2sg0004 GPS power management driver"); >> +MODULE_LICENSE("GPL v2"); >> diff --git a/include/linux/w2sg0004.h b/include/linux/w2sg0004.h >> new file mode 100644 >> index 000000000000..ad0c4a18e01d >> --- /dev/null >> +++ b/include/linux/w2sg0004.h >> @@ -0,0 +1,27 @@ >> +/* >> + * UART slave to allow ON/OFF control of w2sg0004 GPS receiver. >> + * >> + * Copyright (C) 2011 Neil Brown <neil@brown.name> >> + * >> + * This program is free software; you can redistribute it and/or >> + * modify it under the terms of the GNU General Public License >> + * version 2 as published by the Free Software Foundation. >> + * >> + * This program is distributed in the hope that it will be useful, but >> + * WITHOUT ANY WARRANTY; without even the implied warranty of >> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU >> + * General Public License for more details. >> + */ >> + >> + >> + >> +#ifndef __LINUX_W2SG0004_H >> +#define __LINUX_W2SG0004_H >> + >> +#include <linux/regulator/consumer.h> >> + >> +struct w2sg_pdata { > > You don't really support platform_data, so you can move this into the > driver. Yes, I am working on that as recommended by Arnd. > >> + struct regulator *lna_regulator; /* enable LNA power */ >> + int on_off_gpio; /* on-off input of the GPS module */ >> +}; >> +#endif /* __LINUX_W2SG0004_H */ >> -- >> 2.12.2 >> BR and thanks, Nikolaus -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Changes V2: * reduced to submit only w2sg00x4 GPS driver code * add DT node for GTA04 device to make use of the driver * split into base code and a debugging Kconfig option (brings device into false power state after boot) * worked in comments by kbuild robot and Rob Herring 2017-05-21 12:44:07: RFC V1 * RFC concerning new serdev based drivers for Wi2Wi w2sg00x4 GPS module and w2cbw003 bluetooth H. Nikolaus Schaller (5): DT: vendor prefix for Wi2Wi, Inc. DT: misc: w2sg0004: add bindings documentation (GPS module with serdev UART) misc: Add w2sg0004 (gps receiver) power control driver DTS: gta04: add serdev node for w2sg00x4 misc: w2sg0004: add debugging code and Kconfig .../devicetree/bindings/misc/wi2wi,w2sg0004.txt | 24 + .../devicetree/bindings/vendor-prefixes.txt | 1 + arch/arm/boot/dts/omap3-gta04.dtsi | 6 + drivers/misc/Kconfig | 18 + drivers/misc/Makefile | 1 + drivers/misc/w2sg0004.c | 602 +++++++++++++++++++++ include/linux/w2sg0004.h | 27 + 7 files changed, 679 insertions(+) create mode 100644 Documentation/devicetree/bindings/misc/wi2wi,w2sg0004.txt create mode 100644 drivers/misc/w2sg0004.c create mode 100644 include/linux/w2sg0004.h