linux-kernel - Re: [PATCH] regulator:s5m8767 Fully convert to GPIO descriptors

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Message-ID: <a06935f7-8d9a-478b-a3a0-25df3f404b44@189.cn>
Date: Fri, 13 Dec 2024 18:30:57 +0800
From: Song Chen <chensong_2000@....cn>
To: Krzysztof Kozlowski <krzk@...nel.org>, lgirdwood@...il.com,
 broonie@...nel.org, lee@...nel.org, linus.walleij@...aro.org, brgl@...ev.pl
Cc: linux-kernel@...r.kernel.org, linux-gpio@...r.kernel.org,
 linux-samsung-soc@...r.kernel.org
Subject: Re: [PATCH] regulator:s5m8767 Fully convert to GPIO descriptors

Hi Krzysztof,

I noticed that in s5m8767_set_high and s5m8767_set_low, the code looks 
identical to each other, only order is different. Is there any problem 
here or this way is on purpose correctly.

static inline int s5m8767_set_high(struct s5m8767_info *s5m8767)
{
     int temp_index = s5m8767->buck_gpioindex;

     gpio_set_value(s5m8767->buck_gpios[0], (temp_index >> 2) & 0x1);
     gpio_set_value(s5m8767->buck_gpios[1], (temp_index >> 1) & 0x1);
     gpio_set_value(s5m8767->buck_gpios[2], temp_index & 0x1);

     return 0;
}

static inline int s5m8767_set_low(struct s5m8767_info *s5m8767)
{
     int temp_index = s5m8767->buck_gpioindex;

     gpio_set_value(s5m8767->buck_gpios[2], temp_index & 0x1);
     gpio_set_value(s5m8767->buck_gpios[1], (temp_index >> 1) & 0x1);
     gpio_set_value(s5m8767->buck_gpios[0], (temp_index >> 2) & 0x1);

     return 0;
}

Song



> On 07/12/2024 07:16, Song Chen wrote:
>>>>    		}
>>>> -		pdata->buck_gpios[i] = gpio;
>>>> +
>>>> +		/* SET GPIO*/
>>>
>>> What is a SET GPIO?
>>>
>>>> +		snprintf(label, sizeof(label), "%s%d", "S5M8767 SET", i + 1);
>>>
>>> Why using "SET" as name, not the actual name it is used for? Buck DVS?
>>
>> from below snippets:
>> s5m8767_pmic_probe of drivers/regulator/s5m8767.c
>>           ret = devm_gpio_request(&pdev->dev, pdata->buck_gpios[0],
>>                       "S5M8767 SET1");
>>           if (ret)
>>               return ret;
>>
>>           ret = devm_gpio_request(&pdev->dev, pdata->buck_gpios[1],
>>                       "S5M8767 SET2");
>>           if (ret)
>>               return ret;
>>
>>           ret = devm_gpio_request(&pdev->dev, pdata->buck_gpios[2],
>>                       "S5M8767 SET3");
> 
> 
> Yeah, your code is fine.
> 
>>
>> and arch/arm/boot/dts/samsung/exynos5250-spring.dts
>>
>>           s5m8767,pmic-buck-dvs-gpios = <&gpd1 0 GPIO_ACTIVE_LOW>, /* DVS1 */
>>                             <&gpd1 1 GPIO_ACTIVE_LOW>, /* DVS2 */
>>                             <&gpd1 2 GPIO_ACTIVE_LOW>; /* DVS3 */
>>
>>           s5m8767,pmic-buck-ds-gpios = <&gpx2 3 GPIO_ACTIVE_LOW>, /* SET1 */
>>                            <&gpx2 4 GPIO_ACTIVE_LOW>, /* SET2 */
>>                            <&gpx2 5 GPIO_ACTIVE_LOW>; /* SET3 */
>>
>>>
>>>> +		gpiod_set_consumer_name(pdata->buck_gpios[i], label);
>>>> +		gpiod_direction_output(pdata->buck_gpios[i],
>>>> +					(pdata->buck_default_idx >> (2 - i)) & 0x1);
>>>
>>> This is not an equivalent code. You set values for GPIOs 0-1 even if
>>> requesting GPIO 2 fails.
>>>
>>> On which board did you test it?
>>
>> You are right ,it's not equivalent with original code, i will fix it.
>> but i have a question here:
>>
>>           ret = devm_gpio_request(&pdev->dev, pdata->buck_gpios[0],
>>                       "S5M8767 SET1");
>>           if (ret)
>>               return ret;
>>
>>           ret = devm_gpio_request(&pdev->dev, pdata->buck_gpios[1],
>>                       "S5M8767 SET2");
>>           if (ret)
>>               return ret;
>>
>>           ret = devm_gpio_request(&pdev->dev, pdata->buck_gpios[2],
>>                       "S5M8767 SET3");
>>           if (ret)
>>               return ret;
>>
>> if it fails to request buck_gpios[2] after successfully requests
>> buck_gpios[0] and buck_gpios[1], the probe fails as well, should it call
>> gpiod_put to return gpio resource?
> 
> 
> Aren't you using devm interface? Please read the API. You do not need to
> put anything, unless you use some other interface and I missed the point
> of the question.
> 
> Best regards,
> Krzysztof
> 
>