linux-kernel - Re: [PATCH] ASoC: codec: ak5386: Convert to GPIO descriptors

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Message-ID: <20250331060359.GA6762@nxa18884-linux>
Date: Mon, 31 Mar 2025 14:03:59 +0800
From: Peng Fan <peng.fan@....nxp.com>
To: Andy Shevchenko <andriy.shevchenko@...el.com>
Cc: Liam Girdwood <lgirdwood@...il.com>, Mark Brown <broonie@...nel.org>,
	Jaroslav Kysela <perex@...ex.cz>, Takashi Iwai <tiwai@...e.com>,
	Linus Walleij <linus.walleij@...aro.org>,
	Bartosz Golaszewski <brgl@...ev.pl>, Peng Fan <peng.fan@....com>,
	"open list:SOUND - SOC LAYER / DYNAMIC AUDIO POWER MANAGEM..." <linux-sound@...r.kernel.org>,
	open list <linux-kernel@...r.kernel.org>,
	"open list:GPIO SUBSYSTEM:Keyword:(devm_)?gpio_(request|free|direction|get|set)" <linux-gpio@...r.kernel.org>,
	krzk@...nel.org
Subject: Re: [PATCH]  ASoC: codec: ak5386: Convert to GPIO descriptors

On Fri, Mar 28, 2025 at 03:33:11PM +0200, Andy Shevchenko wrote:
>On Fri, Mar 28, 2025 at 07:39:17PM +0800, Peng Fan (OSS) wrote:
>> From: Peng Fan <peng.fan@....com>
>> 
>>  of_gpio.h is deprecated, update the driver to use GPIO descriptors.
>>  - Use dev_gpiod_get_optional to get GPIO descriptor.
>
>devm
>
>>  - Use gpiod_set_value to configure output value.
>> 
>> With legacy of_gpio API, the driver set gpio value 1 to power up
>
>sets GPIO
>
>> AK5386, and set value 0 to power down.
>> Per datasheet for PDN(reset_gpio in the driver):
>>  Power Down & Reset Mode Pin
>>  “H”: Power up, “L”: Power down & Reset
>>  The AK5386 must be reset once upon power-up.
>> 
>> There is no in-tree DTS using this codec, and the dt-bindings not
>
>bindings does not
>
>> specify polarity. Per driver and datasheet, the gpio polarity should be
>
>GPIO
>
>> active-high which is to power up the codec. So using GPIOD_OUT_LOW
>> when get the GPIO descriptor matches GPIOF_OUT_INIT_LOW when using
>> of_gpio API.
>
>...
>
>>  The Documentation/devicetree/bindings/sound/ak5386.txt not specify
>>  polarity(this seems bug), so per code and datasheet, I think it
>>  should be active-high. I could add a quirk in gpiolib-of to force
>>  active-high or acitive-low if you think needed.
>
>I don't think we need a quirk as long as the default is the same,
>I mean if the DTS is written without setting polarity, would it be
>active-high or active-low?

Per current gpio driver, of_gpio_n_cells should at least be 2,
Not find any driver using 1 in current linux tree.

Without polarity, I think of_xlate will not work as expected.

Regards,
Peng

>
>...
>
>> +	if (priv->reset_gpio)
>
>Redundant as it duplicates the one in the below call.
>
>> +		gpiod_set_value(priv->reset_gpio, 1);
>
>...
>
>> +	if (priv->reset_gpio)
>
>Ditto.
>
>> +		gpiod_set_value(priv->reset_gpio, 0);
>
>...
>
>> +	priv->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
>> +	if (IS_ERR(priv->reset_gpio))
>> +		return dev_err_probe(dev, PTR_ERR(priv->reset_gpio),
>
>+ dev_printk.h // or even device.h, depending on the current code base
>+ err.h
>
>> +				     "Failed to get AK5386 reset GPIO\n");
>
>> +	gpiod_set_consumer_name(priv->reset_gpio, "AK5386 Reset");
>
>-- 
>With Best Regards,
>Andy Shevchenko
>
>