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authorMarkus Pargmann <mpa@pengutronix.de>2015-08-14 16:10:59 +0200
committerLinus Walleij <linus.walleij@linaro.org>2015-09-24 10:48:51 -0700
commitc0017ed71966a19ec40c7bc900d4338ddfbc4105 (patch)
tree7353a78f2cbdd6602f83b23f4a5a99fff5af8ae0
parentfd7337fdb9bce420033c28af4c07b73e34e692c1 (diff)
downloadop-kernel-dev-c0017ed71966a19ec40c7bc900d4338ddfbc4105.zip
op-kernel-dev-c0017ed71966a19ec40c7bc900d4338ddfbc4105.tar.gz
gpio: Introduce gpio descriptor 'name'
The latest gpio hogging mechanism assigns each gpio a 'line-name' in the devicetree. The 'name' field is different from the 'label' field. 'label' is only used for requested GPIOs to describe its current use by driver or userspace. The 'name' field describes the GPIO itself, not the use. This is most likely identical to the label in the schematic on the GPIO line and should help to find this particular GPIO. This is equivalent to the gpiochip->names array. However names should be stored in the GPIO descriptor. We will use gpiochip->names in the future only as initializer for the GPIO descriptors for drivers that assign GPIO names hardcoded. All other GPIO names will be parsed from DT and directly assigned to the GPIO descriptor. This patch adds a helper function to find gpio descriptors by name instead of gpio number. Signed-off-by: Markus Pargmann <mpa@pengutronix.de> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
-rw-r--r--drivers/gpio/gpiolib.c32
-rw-r--r--drivers/gpio/gpiolib.h3
-rw-r--r--include/linux/gpio/consumer.h7
3 files changed, 42 insertions, 0 deletions
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 5db3445..697c409 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -90,6 +90,38 @@ struct gpio_desc *gpio_to_desc(unsigned gpio)
EXPORT_SYMBOL_GPL(gpio_to_desc);
/**
+ * Convert a GPIO name to its descriptor
+ */
+struct gpio_desc *gpio_name_to_desc(const char * const name)
+{
+ struct gpio_chip *chip;
+ unsigned long flags;
+
+ spin_lock_irqsave(&gpio_lock, flags);
+
+ list_for_each_entry(chip, &gpio_chips, list) {
+ int i;
+
+ for (i = 0; i != chip->ngpio; ++i) {
+ struct gpio_desc *gpio = &chip->desc[i];
+
+ if (!gpio->name)
+ continue;
+
+ if (!strcmp(gpio->name, name)) {
+ spin_unlock_irqrestore(&gpio_lock, flags);
+ return gpio;
+ }
+ }
+ }
+
+ spin_unlock_irqrestore(&gpio_lock, flags);
+
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(gpio_name_to_desc);
+
+/**
* Get the GPIO descriptor corresponding to the given hw number for this chip.
*/
struct gpio_desc *gpiochip_get_desc(struct gpio_chip *chip,
diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h
index bf34300..78e634d 100644
--- a/drivers/gpio/gpiolib.h
+++ b/drivers/gpio/gpiolib.h
@@ -89,7 +89,10 @@ struct gpio_desc {
#define FLAG_USED_AS_IRQ 9 /* GPIO is connected to an IRQ */
#define FLAG_IS_HOGGED 11 /* GPIO is hogged */
+ /* Connection label */
const char *label;
+ /* Name of the GPIO */
+ const char *name;
};
int gpiod_request(struct gpio_desc *desc, const char *label);
diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
index 14cac67..366a3fd 100644
--- a/include/linux/gpio/consumer.h
+++ b/include/linux/gpio/consumer.h
@@ -130,6 +130,7 @@ int gpiod_to_irq(const struct gpio_desc *desc);
/* Convert between the old gpio_ and new gpiod_ interfaces */
struct gpio_desc *gpio_to_desc(unsigned gpio);
int desc_to_gpio(const struct gpio_desc *desc);
+struct gpio_desc *gpio_name_to_desc(const char *name);
/* Child properties interface */
struct fwnode_handle;
@@ -400,6 +401,12 @@ static inline struct gpio_desc *gpio_to_desc(unsigned gpio)
{
return ERR_PTR(-EINVAL);
}
+
+static inline struct gpio_desc *gpio_name_to_desc(const char *name)
+{
+ return ERR_PTR(-EINVAL);
+}
+
static inline int desc_to_gpio(const struct gpio_desc *desc)
{
/* GPIO can never have been requested */
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