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SubjectRe: [PATCH v4 02/10] pinctrl: axp209: add pinctrl features
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Hi Maxime,

On 01/12/2017 16:57, Maxime Ripard wrote:
> On Fri, Dec 01, 2017 at 02:44:43PM +0100, Quentin Schulz wrote:
>> +static void axp20x_gpio_set(struct gpio_chip *chip, unsigned offset,
>> + int value)
>> +{
>
> checkpatch output:
> WARNING: Prefer 'unsigned int' to bare use of 'unsigned'
>
>> +static int axp20x_pmx_set_mux(struct pinctrl_dev *pctldev,
>> + unsigned int function, unsigned int group)
>> +{
>> + struct axp20x_gpio *gpio = pinctrl_dev_get_drvdata(pctldev);
>> + unsigned int mask;
>> +
>> + /* Every pin supports GPIO_OUT and GPIO_IN functions */
>> + if (function <= AXP20X_FUNC_GPIO_IN)
>> + return axp20x_pmx_set(pctldev, group,
>> + gpio->funcs[function].muxval);
>> +
>> + if (function == AXP20X_FUNC_LDO)
>> + mask = gpio->desc->ldo_mask;
>> + else
>> + mask = gpio->desc->adc_mask;
>
> What is the point of this test...
>
>> + if (!(BIT(group) & mask))
>> + return -EINVAL;
>> +
>> + /*
>> + * We let the regulator framework handle the LDO muxing as muxing bits
>> + * are basically also regulators on/off bits. It's better not to enforce
>> + * any state of the regulator when selecting LDO mux so that we don't
>> + * interfere with the regulator driver.
>> + */
>> + if (function == AXP20X_FUNC_LDO)
>> + return 0;
>
> ... if you know that you're not going to do anything with one of the
> outcomes. It would be better to just move that part above, instead of
> doing the same test twice.
>

Return value is different. In one case, it is an error to request "ldo"
for a pin that does not support it. In the other case, the ldo request
is valid but nothing's done on driver side.

Both cases are handled differently by the core:
http://elixir.free-electrons.com/linux/latest/source/drivers/pinctrl/pinmux.c#L439

I think that's the behavior we're expecting from this driver.

Or maybe you're asking to do:

+ if (function == AXP20X_FUNC_LDO) {
+ if (!(BIT(group) & gpio->desc->ldo_mask))
+ return -EINVAL;
+ return 0;
+ } else if (!(BIT(group) & gpio->desc->adc_mask)) {
+ return -EINVAL;
+ }

?

Thanks,
Quentin
--
Quentin Schulz, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

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