[PATCH 1/5] gpiolib: implement gpio_get_chip_by_dev()

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

gpio_of_xlate() already needs the ability to find a struct gpio_chip *
via a struct device_d. Exporting this functionality to elsewhere in the
code will allow restricting commands to manipulate only a single GPIO
bank.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 drivers/gpio/gpiolib.c | 28 +++++++++++++++++++---------
 include/gpio.h         |  1 +
 2 files changed, 20 insertions(+), 9 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 97a99b84e32a..cf61213ca12d 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -636,6 +636,18 @@ static int of_gpio_simple_xlate(struct gpio_chip *chip,
 	return chip->base + gpiospec->args[0];
 }
 
+struct gpio_chip *gpio_get_chip_by_dev(struct device_d *dev)
+{
+	struct gpio_chip *chip;
+
+	list_for_each_entry(chip, &chip_list, list) {
+		if (chip->dev == dev)
+			return chip;
+	}
+
+	return NULL;
+}
+
 int gpio_of_xlate(struct device_d *dev, struct of_phandle_args *gpiospec, int *flags)
 {
 	struct gpio_chip *chip;
@@ -643,16 +655,14 @@ int gpio_of_xlate(struct device_d *dev, struct of_phandle_args *gpiospec, int *f
 	if (!dev)
 		return -ENODEV;
 
-	list_for_each_entry(chip, &chip_list, list) {
-		if (chip->dev != dev)
-			continue;
-		if (chip->ops->of_xlate)
-			return chip->ops->of_xlate(chip, gpiospec, flags);
-		else
-			return of_gpio_simple_xlate(chip, gpiospec, flags);
-	}
+	chip = gpio_get_chip_by_dev(dev);
+	if (!chip)
+		return -EPROBE_DEFER;
 
-	return -EPROBE_DEFER;
+	if (chip->ops->of_xlate)
+		return chip->ops->of_xlate(chip, gpiospec, flags);
+	else
+		return of_gpio_simple_xlate(chip, gpiospec, flags);
 }
 
 struct gpio_chip *gpio_get_chip(int gpio)
diff --git a/include/gpio.h b/include/gpio.h
index 8218722dcbf0..82f2eb6b8a34 100644
--- a/include/gpio.h
+++ b/include/gpio.h
@@ -190,5 +190,6 @@ void gpiochip_remove(struct gpio_chip *chip);
 
 int gpio_of_xlate(struct device_d *dev, struct of_phandle_args *gpiospec, int *flags);
 struct gpio_chip *gpio_get_chip(int gpio);
+struct gpio_chip *gpio_get_chip_by_dev(struct device_d *);
 
 #endif /* __GPIO_H */
-- 
2.30.2