Re: [PATCH V1] pinctrl: qcom: spmi-gpio: Update GPIO EN_CTL when setting pin config

[Fenglin Wu]

On 10/9/2017 1:56 PM, Bjorn Andersson wrote:
> On Sun 08 Oct 22:34 PDT 2017, Fenglin Wu wrote:
>
> > On 10/6/2017 12:27 AM, Bjorn Andersson wrote:
> > > On Mon 11 Sep 17:32 PDT 2017, fenglinw@xxxxxxxxxxxxxx wrote:
> > >
> > > > From: Fenglin Wu <fenglinw@xxxxxxxxxxxxxx>
> > > >
> > > > GPIO is expected to be disabled iff PIN_CONFIG_BIAS_HIGH_IMPEDANCE is
> > > > configured. Update is_enabled flag in config_set() so that it can
> > > > reflect GPIO status correctly. Also modify EN_CTL register based on
> > > > is_enabled flag in config_set() to configure the GPIO properly.
> > > >
> > > > Signed-off-by: Fenglin Wu <fenglinw@xxxxxxxxxxxxxx>
> > > > ---
> > > >    drivers/pinctrl/qcom/pinctrl-spmi-gpio.c | 5 +++++
> > > >    1 file changed, 5 insertions(+)
> > > >
> > > > diff --git a/drivers/pinctrl/qcom/pinctrl-spmi-gpio.c b/drivers/pinctrl/qcom/pinctrl-spmi-gpio.c
> > > > index c2c0bab..a0edaa8 100644
> > > > --- a/drivers/pinctrl/qcom/pinctrl-spmi-gpio.c
> > > > +++ b/drivers/pinctrl/qcom/pinctrl-spmi-gpio.c
> > > > @@ -453,6 +453,7 @@ static int pmic_gpio_config_set(struct pinctrl_dev *pctldev, unsigned int pin,
> > > >    	pad = pctldev->desc->pins[pin].drv_data;
> > > > +	pad->is_enabled = true;
> > > >    	for (i = 0; i < nconfs; i++) {
> > > >    		param = pinconf_to_config_param(configs[i]);
> > > >    		arg = pinconf_to_config_argument(configs[i]);
> > > > @@ -600,6 +601,10 @@ static int pmic_gpio_config_set(struct pinctrl_dev *pctldev, unsigned int pin,
> > > >    			return ret;
> > > >    	}
> > > > +	val = pad->is_enabled << PMIC_GPIO_REG_MASTER_EN_SHIFT;
> > > > +
> > > > +	ret = pmic_gpio_write(state, pad, PMIC_GPIO_REG_EN_CTL, val);
> > > > +
> > >
> > > This looks good.
> > >
> > > Acked-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
> > >
> > >
> > > But I spotted another issue while reviewing this; currently the initial
> > > state of is_enabled is unconditionally set to enabled in
> > > pmic_gpio_populate(), so reading the initial pinconf or configuring a
> > > pinmux before setting a pinconf will operate on the potentially wrong
> > > information.
> > >
> > > So I think the initial value should be read out from REG_EN_CTL rather
> > > than being just "true".
> > >
> > > Can you please either submit another patch for this?
> >
> > Hmm, considering a GPIO which is disabled by default in hardware
> > setting, what's its expected state if we only define "function" for it?
> > I was thinking we need to enable it once it has any setting in pinmux or
> > pinconf. If you think that we need to keep its original state until we
> > set pinconf for it, yes, I can submit a change to address this.
>
> Are there valid cases where only function should be selected and no
> other configuration is used? If so it makes sense to make
> pmic_gpio_set_mux() enable the block.
>
>
> Regardless of this, if there are disabled pins that are not mentioned in
> DT they will still appear as enabled in the debugfs interface; and this
> I consider an error worth fixing.
How about we do both: read the HW initial state in pmic_gpio_populate(),
and also enable the GPIO block in pmic_gpio_set_mux()?

> Regards,
> Bjorn

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