Thread (15 messages) 15 messages, 4 authors, 2018-03-01

Re: [PATCH v1 3/4] ASoC: codecs: pcm179x: Add reset gpio

From: Mylène Josserand <hidden>
Date: 2018-03-01 08:13:51
Also in: alsa-devel, lkml

Hello Fabio,

Thank you for the review!

On Tue, 27 Feb 2018 19:30:11 -0300
Fabio Estevam [off-list ref] wrote:
On Tue, Feb 27, 2018 at 6:24 PM, Mylène Josserand
[off-list ref] wrote:
quoted
+       pcm179x->reset = of_get_named_gpio(np, "reset-gpios", 0);
+       if (gpio_is_valid(pcm179x->reset)) {
+               ret = devm_gpio_request_one(dev, pcm179x->reset,
+                                           GPIOF_OUT_INIT_LOW,
+                                           "pcm179x reset");
+               if (ret) {
+                       dev_err(dev,
+                               "Failed to request GPIO %d as reset pin, error %d\n",
+                               pcm179x->reset, ret);
+                       return ret;
+               }
+
+               gpio_set_value(pcm179x->reset, 1);  
It would be better to use the gpiod API, which takes the GPIO polarity
into account.

There may be systems that have an inverter connected to this pin, and
this can be changed in dts via GPIO_ACTIVE_HIGH.
Oh, true, I should have used gpiod. Thanks for pointing me out.
Also, as the reset pin can be connected to an I2C expander, for
example, so it is safer to use the cansleep variant:

gpiod_set_value_cansleep(pcm179x->reset, 0);
Sure, I will update it.

Thanks,

Mylène

-- 
Mylène Josserand, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
http://bootlin.com
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