Re: [PATCH] gpio: pca953x: Add optional reset gpio control

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On 01/04/2017 02:25 AM, Vladimir Zapolskiy wrote:
Hi Steve,

On 01/02/2017 11:07 PM, Steve Longerbeam wrote:
Add optional reset-gpios pin control. If present, de-assert the
specified reset gpio pin to bring the chip out of reset.

Signed-off-by: Steve Longerbeam <steve_longerbeam@xxxxxxxxxx>
Cc: Linus Walleij <linus.walleij@xxxxxxxxxx>
Cc: Alexandre Courbot <gnurou@xxxxxxxxx>
Cc: linux-gpio@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
  Documentation/devicetree/bindings/gpio/gpio-pca953x.txt |  4 ++++
  drivers/gpio/gpio-pca953x.c                             | 11 +++++++++++
  2 files changed, 15 insertions(+)

diff --git a/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt b/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt
index 08dd15f..da54f4c 100644
--- a/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt
+++ b/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt
@@ -29,6 +29,10 @@ Required properties:
  	onsemi,pca9654
  	exar,xra1202
+Optional properties:
+ - reset-gpios: GPIO specification for the RESET input
+
+
Drop the surplus empty line above.

done.


  Example:
diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
index d5d72d8..ca2ddea 100644
--- a/drivers/gpio/gpio-pca953x.c
+++ b/drivers/gpio/gpio-pca953x.c
@@ -22,6 +22,7 @@
  #include <linux/of_platform.h>
  #include <linux/acpi.h>
  #include <linux/regulator/consumer.h>
+#include <linux/gpio/consumer.h>
#define PCA953X_INPUT 0
  #define PCA953X_OUTPUT		1
@@ -754,8 +755,18 @@ static int pca953x_probe(struct i2c_client *client,
  		invert = pdata->invert;
  		chip->names = pdata->names;
  	} else {
+		struct gpio_desc *reset_gpio;
+
  		chip->gpio_start = -1;
  		irq_base = 0;
+
+		/* see if we need to de-assert a reset pin */
+		reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
+						     GPIOD_OUT_LOW);
+		if (IS_ERR(reset_gpio)) {
+			dev_err(&client->dev, "request for reset pin failed\n");
I'm not confident that the error message is wanted here, you may consider either
to remove it or at least print it out if (PTR_ERR(reset_gpio) != -EPROBE_DEFER).

no problem, I just removed it.


Steve

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