diff mbox

[36/43] gpio: pca953x: Add reset-gpios property

Message ID 1402178205-22697-37-git-send-email-steve_longerbeam@mentor.com (mailing list archive)
State New, archived
Headers show

Commit Message

Steve Longerbeam June 7, 2014, 9:56 p.m. UTC
Add optional reset-gpios property. If present, de-assert the
specified reset gpio pin to bring the chip out of reset.

Signed-off-by: Steve Longerbeam <steve_longerbeam@mentor.com>
---
 drivers/gpio/gpio-pca953x.c |   26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

Comments

Philipp Zabel June 11, 2014, 11:39 a.m. UTC | #1
Am Samstag, den 07.06.2014, 14:56 -0700 schrieb Steve Longerbeam:
[...]
>  static int pca953x_read_single(struct pca953x_chip *chip, int reg, u32 *val,
> @@ -735,6 +741,26 @@ static int pca953x_probe(struct i2c_client *client,
>  		/* If I2C node has no interrupts property, disable GPIO interrupts */
>  		if (of_find_property(client->dev.of_node, "interrupts", NULL) == NULL)
>  			irq_base = -1;
> +
> +		/* see if we need to de-assert a reset pin */
> +		ret = of_get_named_gpio_flags(client->dev.of_node,
> +					      "reset-gpios", 0,
> +					      &chip->reset_gpio_flags);
> +		if (gpio_is_valid(ret)) {
> +			chip->reset_gpio = ret;
> +			ret = devm_gpio_request_one(&client->dev,
> +						    chip->reset_gpio,
> +						    GPIOF_DIR_OUT,
> +						    "pca953x_reset");
> +			if (ret == 0) {
> +				/* bring chip out of reset */
> +				dev_info(&client->dev, "releasing reset\n");

I think dev_dbg would be more appropriate.

> +				gpio_set_value(chip->reset_gpio,
> +					       (chip->reset_gpio_flags ==
> +						OF_GPIO_ACTIVE_LOW) ? 1 : 0);
> +			}

You could use the gpiod API (include/gpio/consumer.h) here and have it
do the polarity handling automatically.

regards
Philipp

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diff mbox

Patch

diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
index d550d8e..6e212f7 100644
--- a/drivers/gpio/gpio-pca953x.c
+++ b/drivers/gpio/gpio-pca953x.c
@@ -22,6 +22,7 @@ 
 #include <linux/slab.h>
 #ifdef CONFIG_OF_GPIO
 #include <linux/of_platform.h>
+#include <linux/of_gpio.h>
 #endif
 
 #define PCA953X_INPUT		0
@@ -98,6 +99,11 @@  struct pca953x_chip {
 	struct gpio_chip gpio_chip;
 	const char *const *names;
 	int	chip_type;
+
+#ifdef CONFIG_OF_GPIO
+	enum of_gpio_flags reset_gpio_flags;
+	int reset_gpio;
+#endif
 };
 
 static int pca953x_read_single(struct pca953x_chip *chip, int reg, u32 *val,
@@ -735,6 +741,26 @@  static int pca953x_probe(struct i2c_client *client,
 		/* If I2C node has no interrupts property, disable GPIO interrupts */
 		if (of_find_property(client->dev.of_node, "interrupts", NULL) == NULL)
 			irq_base = -1;
+
+		/* see if we need to de-assert a reset pin */
+		ret = of_get_named_gpio_flags(client->dev.of_node,
+					      "reset-gpios", 0,
+					      &chip->reset_gpio_flags);
+		if (gpio_is_valid(ret)) {
+			chip->reset_gpio = ret;
+			ret = devm_gpio_request_one(&client->dev,
+						    chip->reset_gpio,
+						    GPIOF_DIR_OUT,
+						    "pca953x_reset");
+			if (ret == 0) {
+				/* bring chip out of reset */
+				dev_info(&client->dev, "releasing reset\n");
+				gpio_set_value(chip->reset_gpio,
+					       (chip->reset_gpio_flags ==
+						OF_GPIO_ACTIVE_LOW) ? 1 : 0);
+			}
+		} else if (ret == -EPROBE_DEFER)
+			return ret;
 #endif
 	}