Hi,
On Mon, Dec 04, 2017 at 09:07:52AM +0100, Quentin Schulz wrote:
> >> +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.
Ah, right.
> 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;
> + }
>
> ?
No, it's definitely better the way you did it.
Maxime
--
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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