Re: [PATCH 10/20] gpio: pca953x: Add optional reset gpio control
From: Linus Walleij <hidden>
Date: 2016-12-30 13:17:41
Also in:
linux-arm-kernel, linux-gpio, linux-media, lkml
On Thu, Dec 29, 2016 at 11:27 PM, Steve Longerbeam [off-list ref] 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 <redacted> Cc: Linus Walleij <redacted> Cc: Alexandre Courbot <redacted> Cc: linux-gpio@vger.kernel.org Cc: linux-kernel@vger.kernel.org
This seems like a separate patch from the other 19 patches so please send it separately so I can handle logistics easier in the future.
quoted hunk ↗ jump to hunk
@@ -133,6 +134,7 @@ struct pca953x_chip { const char *const *names; unsigned long driver_data; struct regulator *regulator; + struct gpio_desc *reset_gpio;
Why do you even keep this around in the device state container? As you only use it in the probe() function, use a local variable. The descriptor will be free():ed by the devm infrastructure anyways.
quoted hunk ↗ jump to hunk
+ /* see if we need to de-assert a reset pin */ + chip->reset_gpio = devm_gpiod_get_optional(&client->dev, + "reset", + GPIOD_OUT_LOW); + if (IS_ERR(chip->reset_gpio)) { + dev_err(&client->dev, "request for reset pin failed\n"); + return PTR_ERR(chip->reset_gpio); + }
Nice.
quoted hunk ↗ jump to hunk
+ if (chip->reset_gpio) { + /* bring chip out of reset */ + dev_info(&client->dev, "releasing reset\n"); + gpiod_set_value(chip->reset_gpio, 0); + }
Is this really needed given that you set it low in the devm_gpiod_get_optional()? Yours, Linus Walleij