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Subject[PATCH 1/1] gpio: introduce gpio_export_array to ease export for gpio arrays
Date
Introduce gpio_export_array function to ease the export operation
for gpio arrays.
This can cooperate with the exist gpio_request_array function.

Signed-off-by: Dong Aisheng <dong.aisheng@linaro.org>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Arnd Bergmann <arnd@arndb.de>

---
We already have gpio_request_array, i'm wondering if we can have
a gpio_export_array to cooperate to ease the export operation
for gpio arrays.
---
drivers/gpio/gpiolib.c | 35 +++++++++++++++++++++++++++++++++++
include/asm-generic/gpio.h | 14 ++++++++++++++
include/linux/gpio.h | 15 +++++++++++++++
3 files changed, 64 insertions(+), 0 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index a971e3d..e9f2374 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -816,6 +816,29 @@ done:
}
EXPORT_SYMBOL_GPL(gpio_export_link);

+/**
+ * gpio_export_array - export multiple GPIOs in a single call
+ * @array: array of the 'struct gpio'
+ * @num: how many GPIOs in the array
+ */
+int gpio_export_array(const struct gpio *array, size_t num,
+ bool direction_may_change)
+{
+ int i, err;
+
+ for (i = 0; i < num; i++, array++) {
+ err = gpio_export(array->gpio, direction_may_change);
+ if (err)
+ goto err_export;
+ }
+ return 0;
+
+err_export:
+ while (i--)
+ gpio_unexport((--array)->gpio);
+ return err;
+}
+EXPORT_SYMBOL_GPL(gpio_export_array);

/**
* gpio_sysfs_set_active_low - set the polarity of gpio sysfs value
@@ -903,6 +926,18 @@ done:
}
EXPORT_SYMBOL_GPL(gpio_unexport);

+/**
+ * gpio_unexport_array - unexport multiple GPIOs in a single call
+ * @array: array of the 'struct gpio'
+ * @num: how many GPIOs in the array
+ */
+void gpio_unexport_array(const struct gpio *array, size_t num)
+{
+ while (num--)
+ gpio_unexport((array++)->gpio);
+}
+EXPORT_SYMBOL_GPL(gpio_unexport_array);
+
static int gpiochip_export(struct gpio_chip *chip)
{
int status;
diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index 8c86210..ed0ce4d 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -182,10 +182,13 @@ extern void gpio_free_array(const struct gpio *array, size_t num);
* but more typically is configured entirely from userspace.
*/
extern int gpio_export(unsigned gpio, bool direction_may_change);
+extern int gpio_export_array(const struct gpio *array, size_t num,
+ bool direction_may_change);
extern int gpio_export_link(struct device *dev, const char *name,
unsigned gpio);
extern int gpio_sysfs_set_active_low(unsigned gpio, int value);
extern void gpio_unexport(unsigned gpio);
+extern void gpio_unexport_array(const struct gpio *array, size_t num);

#endif /* CONFIG_GPIO_SYSFS */

@@ -237,6 +240,12 @@ static inline int gpio_export_link(struct device *dev, const char *name,
return -ENOSYS;
}

+static inline int gpio_export_array(const struct gpio *array, size_t num,
+ bool direction_may_change)
+{
+ return -ENOSYS;
+}
+
static inline int gpio_sysfs_set_active_low(unsigned gpio, int value)
{
return -ENOSYS;
@@ -245,6 +254,11 @@ static inline int gpio_sysfs_set_active_low(unsigned gpio, int value)
static inline void gpio_unexport(unsigned gpio)
{
}
+
+static inline void gpio_unexport_array(const struct gpio *array,
+ size_t num)
+{
+}
#endif /* CONFIG_GPIO_SYSFS */

#endif /* _ASM_GENERIC_GPIO_H */
diff --git a/include/linux/gpio.h b/include/linux/gpio.h
index 38ac48b..9b5aae5 100644
--- a/include/linux/gpio.h
+++ b/include/linux/gpio.h
@@ -138,6 +138,14 @@ static inline int gpio_export_link(struct device *dev, const char *name,
return -EINVAL;
}

+static inline int gpio_export_array(const struct gpio *array, size_t num,
+ bool direction_may_change)
+{
+ /* GPIO can never have been requested or set as {in,out}put */
+ WARN_ON(1);
+ return -EINVAL;
+}
+
static inline int gpio_sysfs_set_active_low(unsigned gpio, int value)
{
/* GPIO can never have been requested */
@@ -151,6 +159,13 @@ static inline void gpio_unexport(unsigned gpio)
WARN_ON(1);
}

+static inline void gpio_unexport_array(const struct gpio *array,
+ size_t num)
+{
+ /* GPIO array can never have been exported */
+ WARN_ON(1);
+}
+
static inline int gpio_to_irq(unsigned gpio)
{
/* GPIO can never have been requested or set as input */
--
1.7.0.4



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