@@ -153,6 +153,9 @@ struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id,
*flags |= GPIO_OPEN_SOURCE;
}
+ if (of_flags & OF_GPIO_TRANSITORY)
+ *flags |= GPIO_TRANSITORY;
+
return desc;
}
@@ -206,6 +209,8 @@ static struct gpio_desc *of_parse_own_gpio(struct device_node *np,
if (xlate_flags & OF_GPIO_ACTIVE_LOW)
*lflags |= GPIO_ACTIVE_LOW;
+ if (xlate_flags & OF_GPIO_TRANSITORY)
+ *lflags |= GPIO_TRANSITORY;
if (of_property_read_bool(np, "input"))
*dflags |= GPIOD_IN;
@@ -468,11 +468,15 @@ static ssize_t export_store(struct class *class,
status = -ENODEV;
goto done;
}
- status = gpiod_export(desc, true);
- if (status < 0)
- gpiod_free(desc);
- else
- set_bit(FLAG_SYSFS, &desc->flags);
+
+ status = gpiod_set_transitory(desc, false);
+ if (!status) {
+ status = gpiod_export(desc, true);
+ if (status < 0)
+ gpiod_free(desc);
+ else
+ set_bit(FLAG_SYSFS, &desc->flags);
+ }
done:
if (status)
@@ -479,6 +479,10 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip)
if (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE)
set_bit(FLAG_OPEN_SOURCE, &desc->flags);
+ ret = gpiod_set_transitory(desc, false);
+ if (ret < 0)
+ goto out_free_descs;
+
/*
* Lines have to be requested explicitly for input
* or output, else the line will be treated "as is".
@@ -2406,6 +2410,49 @@ int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce)
}
EXPORT_SYMBOL_GPL(gpiod_set_debounce);
+/**
+ * gpiod_set_transitory - Lose or retain GPIO state on suspend or reset
+ * @desc: descriptor of the GPIO for which to configure persistence
+ * @transitory: True to lose state on suspend or reset, false for persistence
+ *
+ * Returns:
+ * 0 on success, otherwise a negative error code.
+ */
+int gpiod_set_transitory(struct gpio_desc *desc, bool transitory)
+{
+ struct gpio_chip *chip;
+ unsigned long packed;
+ int gpio;
+ int rc;
+
+ /*
+ * Handle FLAG_TRANSITORY first, enabling queries to gpiolib for
+ * persistence state.
+ */
+ if (transitory)
+ set_bit(FLAG_TRANSITORY, &desc->flags);
+ else
+ clear_bit(FLAG_TRANSITORY, &desc->flags);
+
+ /* If the driver supports it, set the persistence state now */
+ chip = desc->gdev->chip;
+ if (!chip->set_config)
+ return 0;
+
+ packed = pinconf_to_config_packed(PIN_CONFIG_PERSIST_STATE,
+ !transitory);
+ gpio = gpio_chip_hwgpio(desc);
+ rc = chip->set_config(chip, gpio, packed);
+ if (rc == -ENOTSUPP) {
+ dev_dbg(&desc->gdev->dev, "Persistence not supported for GPIO %d\n",
+ gpio);
+ return 0;
+ }
+
+ return rc;
+}
+EXPORT_SYMBOL_GPL(gpiod_set_transitory);
+
/**
* gpiod_is_active_low - test whether a GPIO is active-low or not
* @desc: the gpio descriptor to test
@@ -2885,6 +2932,15 @@ bool gpiochip_line_is_open_source(struct gpio_chip *chip, unsigned int offset)
}
EXPORT_SYMBOL_GPL(gpiochip_line_is_open_source);
+bool gpiochip_line_is_persistent(struct gpio_chip *chip, unsigned int offset)
+{
+ if (offset >= chip->ngpio)
+ return false;
+
+ return !test_bit(FLAG_TRANSITORY, &chip->gpiodev->descs[offset].flags);
+}
+EXPORT_SYMBOL_GPL(gpiochip_line_is_persistent);
+
/**
* gpiod_get_raw_value_cansleep() - return a gpio's raw value
* @desc: gpio whose value will be returned
@@ -3240,6 +3296,10 @@ static int gpiod_configure_flags(struct gpio_desc *desc, const char *con_id,
if (lflags & GPIO_OPEN_SOURCE)
set_bit(FLAG_OPEN_SOURCE, &desc->flags);
+ status = gpiod_set_transitory(desc, (lflags & GPIO_TRANSITORY));
+ if (status < 0)
+ return status;
+
/* No particular flag request, return here... */
if (!(dflags & GPIOD_FLAGS_BIT_DIR_SET)) {
pr_debug("no flags found for %s\n", con_id);
@@ -3348,6 +3408,7 @@ struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode,
bool active_low = false;
bool single_ended = false;
bool open_drain = false;
+ bool transitory = false;
int ret;
if (!fwnode)
@@ -3362,6 +3423,7 @@ struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode,
active_low = flags & OF_GPIO_ACTIVE_LOW;
single_ended = flags & OF_GPIO_SINGLE_ENDED;
open_drain = flags & OF_GPIO_OPEN_DRAIN;
+ transitory = flags & OF_GPIO_TRANSITORY;
}
} else if (is_acpi_node(fwnode)) {
struct acpi_gpio_info info;
@@ -3388,6 +3450,9 @@ struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode,
lflags |= GPIO_OPEN_SOURCE;
}
+ if (transitory)
+ lflags |= GPIO_TRANSITORY;
+
ret = gpiod_configure_flags(desc, propname, lflags, dflags);
if (ret < 0) {
gpiod_put(desc);
@@ -189,6 +189,7 @@ struct gpio_desc {
#define FLAG_OPEN_SOURCE 8 /* Gpio is open source type */
#define FLAG_USED_AS_IRQ 9 /* GPIO is connected to an IRQ */
#define FLAG_IS_HOGGED 11 /* GPIO is hogged */
+#define FLAG_TRANSITORY 12 /* GPIO may lose value in sleep or reset */
/* Connection label */
const char *label;
@@ -28,4 +28,8 @@
#define GPIO_OPEN_DRAIN (GPIO_SINGLE_ENDED | GPIO_LINE_OPEN_DRAIN)
#define GPIO_OPEN_SOURCE (GPIO_SINGLE_ENDED | GPIO_LINE_OPEN_SOURCE)
+/* Bit 3 express GPIO suspend/resume and reset persistence */
+#define GPIO_PERSISTENT 0
+#define GPIO_TRANSITORY 8
+
#endif
@@ -121,6 +121,7 @@ void gpiod_set_raw_array_value_cansleep(unsigned int array_size,
int *value_array);
int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce);
+int gpiod_set_transitory(struct gpio_desc *desc, bool transitory);
int gpiod_is_active_low(const struct gpio_desc *desc);
int gpiod_cansleep(const struct gpio_desc *desc);
@@ -378,6 +379,13 @@ static inline int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce)
return -ENOSYS;
}
+static inline int gpiod_set_transitory(struct gpio_desc *desc, bool transitory)
+{
+ /* GPIO can never have been requested */
+ WARN_ON(1);
+ return -ENOSYS;
+}
+
static inline int gpiod_is_active_low(const struct gpio_desc *desc)
{
/* GPIO can never have been requested */
@@ -9,6 +9,8 @@ enum gpio_lookup_flags {
GPIO_ACTIVE_LOW = (1 << 0),
GPIO_OPEN_DRAIN = (1 << 1),
GPIO_OPEN_SOURCE = (1 << 2),
+ GPIO_PERSISTENT = (0 << 3),
+ GPIO_TRANSITORY = (1 << 3),
};
/**
@@ -31,6 +31,7 @@ enum of_gpio_flags {
OF_GPIO_ACTIVE_LOW = 0x1,
OF_GPIO_SINGLE_ENDED = 0x2,
OF_GPIO_OPEN_DRAIN = 0x4,
+ OF_GPIO_TRANSITORY = 0x8,
};
#ifdef CONFIG_OF_GPIO
@@ -83,6 +83,11 @@
* @PIN_CONFIG_SLEW_RATE: if the pin can select slew rate, the argument to
* this parameter (on a custom format) tells the driver which alternative
* slew rate to use.
+ * @PIN_CONFIG_SKEW_DELAY: if the pin has programmable skew rate (on inputs)
+ * or latch delay (on outputs) this parameter (in a custom format)
+ * specifies the clock skew or latch delay. It typically controls how
+ * many double inverters are put in front of the line.
+ * @PIN_CONFIG_PERSIST_STATE: retain pin state across sleep or controller reset
* @PIN_CONFIG_END: this is the last enumerator for pin configurations, if
* you need to pass in custom configurations to the pin controller, use
* PIN_CONFIG_END+1 as the base offset.
@@ -106,7 +111,10 @@ enum pin_config_param {
PIN_CONFIG_OUTPUT,
PIN_CONFIG_POWER_SOURCE,
PIN_CONFIG_SLEW_RATE,
- PIN_CONFIG_END = 0x7FFF,
+ PIN_CONFIG_SKEW_DELAY,
+ PIN_CONFIG_PERSIST_STATE,
+ PIN_CONFIG_END = 0x7F,
+ PIN_CONFIG_MAX = 0xFF,
};
/*