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Subject[PATCH 1/7] gpiolib: gpiolib-of: Implement device tree gpio-names based lookup
Date
This patch provides of_get_gpiod_flags_by_name(), which looks up GPIO
phandles by name only, through gpios/gpio-names, and not by index.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
---
drivers/gpio/gpiolib-of.c | 48 +++++++++++++++++++++++++++++++++++++++++++++++
include/linux/of_gpio.h | 3 +++
2 files changed, 51 insertions(+)

diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
index 2024d45..5c586fa 100644
--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -97,6 +97,54 @@ struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
EXPORT_SYMBOL(of_get_named_gpiod_flags);

/**
+ * of_get_gpiod_flags_by_name() - Get a GPIO descriptor and flags by name
+ * @np: device node to get GPIO from
+ * @name: matching name of gpio phandle
+ * @flags: a flags pointer to fill in
+ *
+ * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
+ * value on the error condition. If @flags is not NULL the function also fills
+ * in flags for the GPIO.
+ */
+struct gpio_desc *of_get_gpiod_flags_by_name(struct device_node *np,
+ const char *name, enum of_gpio_flags *flags)
+{
+ /* Return -EPROBE_DEFER to support probe() functions to be called
+ * later when the GPIO actually becomes available
+ */
+ struct gg_data gg_data = {
+ .flags = flags,
+ .out_gpio = ERR_PTR(-EPROBE_DEFER)
+ };
+ int index = 0;
+ int ret;
+
+ /* exit if no name given */
+ if (!name)
+ return ERR_PTR(-EINVAL);
+
+ /* .of_xlate might decide to not fill in the flags, so clear it. */
+ if (flags)
+ *flags = 0;
+
+ if (name)
+ index = of_property_match_string(np, "gpio-names", name);
+
+ ret = of_parse_phandle_with_args(np, "gpios", "#gpio-cells", index,
+ &gg_data.gpiospec);
+
+ if (ret)
+ return ERR_PTR(ret);
+
+ gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
+
+ of_node_put(gg_data.gpiospec.np);
+
+ return gg_data.out_gpio;
+}
+EXPORT_SYMBOL(of_get_gpiod_flags_by_names);
+
+/**
* of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
* @gc: pointer to the gpio_chip structure
* @np: device node of the GPIO chip
diff --git a/include/linux/of_gpio.h b/include/linux/of_gpio.h
index f14123a..134331f 100644
--- a/include/linux/of_gpio.h
+++ b/include/linux/of_gpio.h
@@ -51,6 +51,9 @@ static inline struct of_mm_gpio_chip *to_of_mm_gpio_chip(struct gpio_chip *gc)
extern struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
const char *list_name, int index, enum of_gpio_flags *flags);

+extern struct gpio_desc *of_get_gpiod_flags_by_name(struct device_node *np,
+ const char *name, enum of_gpio_flags *flags);
+
extern int of_mm_gpiochip_add(struct device_node *np,
struct of_mm_gpio_chip *mm_gc);

--
1.9.1


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