[PATCH] GPIO: Add gpio_to_desc helper

[Alexander Shiyan]

Patch adds gpio_to_desc helper for validate GPIO.
A bit optimization is performed (about -250 bytes on ARM).

Signed-off-by: Alexander Shiyan <shc_w...@mail.ru>
---
 drivers/gpio/gpiolib.c | 97 ++++++++++++++++++++++++++------------------------
 1 file changed, 51 insertions(+), 46 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 6398268..d7aa094 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -32,20 +32,30 @@ static int gpio_ensure_requested(struct gpio_info *gi, int 
gpio)
        return gpio_request(gpio, "gpio");
 }
 
+static struct gpio_info *gpio_to_desc(unsigned gpio)
+{
+       if (!gpio_is_valid(gpio))
+               return NULL;
+
+       if (!gpio_desc[gpio].chip)
+               return NULL;
+
+       return &gpio_desc[gpio];
+}
+
 int gpio_request(unsigned gpio, const char *label)
 {
-       struct gpio_info *gi = &gpio_desc[gpio];
-       struct gpio_chip *chip = gi->chip;
+       struct gpio_info *gi = gpio_to_desc(gpio);
        int ret;
 
-       if (!gpio_is_valid(gpio))
-               return -EINVAL;
-       if (!chip)
-               return -EINVAL;
+       if (!gi)
+               return -ENODEV;
+
        if (gi->requested)
                return -EBUSY;
-       if (chip->ops->request) {
-               ret = chip->ops->request(chip, gpio - chip->base);
+
+       if (gi->chip->ops->request) {
+               ret = gi->chip->ops->request(gi->chip, gpio - gi->chip->base);
                if (ret)
                        return ret;
        }
@@ -58,17 +68,16 @@ int gpio_request(unsigned gpio, const char *label)
 
 void gpio_free(unsigned gpio)
 {
-       struct gpio_info *gi = &gpio_desc[gpio];
-       struct gpio_chip *chip = gi->chip;
+       struct gpio_info *gi = gpio_to_desc(gpio);
 
-       if (!gpio_is_valid(gpio))
-               return;
-       if (!chip)
+       if (!gi)
                return;
+
        if (!gi->requested)
                return;
-       if (chip->ops->free)
-               chip->ops->free(chip, gpio - chip->base);
+
+       if (gi->chip->ops->free)
+               gi->chip->ops->free(gi->chip, gpio - gi->chip->base);
 
        gi->requested = false;
        free(gi->label);
@@ -76,75 +85,71 @@ void gpio_free(unsigned gpio)
 
 void gpio_set_value(unsigned gpio, int value)
 {
-       struct gpio_info *gi = &gpio_desc[gpio];
-       struct gpio_chip *chip = gi->chip;
+       struct gpio_info *gi = gpio_to_desc(gpio);
 
-       if (!gpio_is_valid(gpio))
-               return;
-       if (!chip)
+       if (!gi)
                return;
+
        if (gpio_ensure_requested(gi, gpio))
                return;
-       if (!chip->ops->set)
-               return;
-       chip->ops->set(chip, gpio - chip->base, value);
+
+       if (gi->chip->ops->set)
+               gi->chip->ops->set(gi->chip, gpio - gi->chip->base, value);
 }
 EXPORT_SYMBOL(gpio_set_value);
 
 int gpio_get_value(unsigned gpio)
 {
-       struct gpio_info *gi = &gpio_desc[gpio];
-       struct gpio_chip *chip = gi->chip;
+       struct gpio_info *gi = gpio_to_desc(gpio);
        int ret;
 
-       if (!gpio_is_valid(gpio))
-               return -EINVAL;
-       if (!chip)
+       if (!gi)
                return -ENODEV;
+
        ret = gpio_ensure_requested(gi, gpio);
        if (ret)
                return ret;
-       if (!chip->ops->get)
+
+       if (!gi->chip->ops->get)
                return -ENOSYS;
-       return chip->ops->get(chip, gpio - chip->base);
+       return gi->chip->ops->get(gi->chip, gpio - gi->chip->base);
 }
 EXPORT_SYMBOL(gpio_get_value);
 
 int gpio_direction_output(unsigned gpio, int value)
 {
-       struct gpio_info *gi = &gpio_desc[gpio];
-       struct gpio_chip *chip = gi->chip;
+       struct gpio_info *gi = gpio_to_desc(gpio);
        int ret;
 
-       if (!gpio_is_valid(gpio))
-               return -EINVAL;
-       if (!chip)
+       if (!gi)
                return -ENODEV;
+
        ret = gpio_ensure_requested(gi, gpio);
        if (ret)
                return ret;
-       if (!chip->ops->direction_output)
+
+       if (!gi->chip->ops->direction_output)
                return -ENOSYS;
-       return chip->ops->direction_output(chip, gpio - chip->base, value);
+       return gi->chip->ops->direction_output(gi->chip, gpio - gi->chip->base,
+                                              value);
 }
 EXPORT_SYMBOL(gpio_direction_output);
 
 int gpio_direction_input(unsigned gpio)
 {
-       struct gpio_info *gi = &gpio_desc[gpio];
-       struct gpio_chip *chip = gi->chip;
+       struct gpio_info *gi = gpio_to_desc(gpio);
        int ret;
 
-       if (!gpio_is_valid(gpio))
-               return -EINVAL;
-       if (!chip)
+       if (!gi)
                return -ENODEV;
+
        ret = gpio_ensure_requested(gi, gpio);
        if (ret)
                return ret;
-       if (!chip->ops->direction_input)
+
+       if (!gi->chip->ops->direction_input)
                return -ENOSYS;
-       return chip->ops->direction_input(chip, gpio - chip->base);
+       return gi->chip->ops->direction_input(gi->chip, gpio - gi->chip->base);
 }
 EXPORT_SYMBOL(gpio_direction_input);
 
@@ -224,9 +229,9 @@ static int do_gpiolib(int argc, char *argv[])
        printf("%*crequested  label\n", 11, ' ');
 
        for (i = 0; i < ARCH_NR_GPIOS; i++) {
-               struct gpio_info *gi = &gpio_desc[i];
+               struct gpio_info *gi = gpio_to_desc(i);
 
-               if (!gi->chip)
+               if (!gi)
                        continue;
 
                printf("gpio %*d: %*s  %s\n", 4,
-- 
1.8.1.5


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