RE: [PATCH] pinctrl: at91: add the config GPIO_OUTPUT_x

From: Yang, Wenyou
Date: Tue Mar 11 2014 - 02:55:03 EST

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In reply to: Jean-Christophe PLAGNIOL-VILLARD: "Re: [PATCH] pinctrl: at91: add the config GPIO_OUTPUT_x"
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> -----Original Message-----
> From: Jean-Christophe PLAGNIOL-VILLARD [mailto:plagnioj@xxxxxxxxxxxx]
> Sent: Tuesday, March 11, 2014 12:16 PM
> To: Yang, Wenyou
> Cc: Jean-Christophe PLAGNIOL-VILLARD; mark.rutland@xxxxxxx;
> devicetree@xxxxxxxxxxxxxxx; pawel.moll@xxxxxxx;
> ijc+devicetree@xxxxxxxxxxxxxx; linus.walleij@xxxxxxxxxx; Linux Kernel
> list; b.brezillon@xxxxxxxxxxx; robh+dt@xxxxxxxxxx; galak@xxxxxxxxxxxxxx;
> <linux-arm-kernel@xxxxxxxxxxxxxxxxxxx> mailing list
> Subject: Re: [PATCH] pinctrl: at91: add the config GPIO_OUTPUT_x
>
>
> On Mar 11, 2014, at 9:28 AM, Yang, Wenyou <Wenyou.Yang@xxxxxxxxx> wrote:
>
> > Hi JC,
> >
> >> -----Original Message-----
> >> From: Yang, Wenyou
> >> Sent: Wednesday, March 05, 2014 1:32 PM
> >> To: Jean-Christophe PLAGNIOL-VILLARD
> >> Cc: linus.walleij@xxxxxxxxxx; b.brezillon@xxxxxxxxxxx; <linux-arm-
> >> kernel@xxxxxxxxxxxxxxxxxxx> mailing list; Linux Kernel list;
> >> devicetree@xxxxxxxxxxxxxxx; robh+dt@xxxxxxxxxx; pawel.moll@xxxxxxx;
> >> mark.rutland@xxxxxxx; ijc+devicetree@xxxxxxxxxxxxxx;
> >> galak@xxxxxxxxxxxxxx
> >> Subject: RE: [PATCH] pinctrl: at91: add the config GPIO_OUTPUT_x
> >>
> >> Hi JC,
> >>
> >>> -----Original Message-----
> >>> From: Jean-Christophe PLAGNIOL-VILLARD
> >>> [mailto:plagnioj@xxxxxxxxxxxx]
> >>> Sent: Wednesday, March 05, 2014 12:58 PM
> >>> To: Yang, Wenyou
> >>> Cc: Jean-Christophe PLAGNIOL-VILLARD; linus.walleij@xxxxxxxxxx;
> >>> b.brezillon@xxxxxxxxxxx; <linux-arm-kernel@xxxxxxxxxxxxxxxxxxx>
> >>> mailing list; Linux Kernel list; devicetree@xxxxxxxxxxxxxxx;
> >>> robh+dt@xxxxxxxxxx; pawel.moll@xxxxxxx; mark.rutland@xxxxxxx;
> >>> ijc+devicetree@xxxxxxxxxxxxxx; galak@xxxxxxxxxxxxxx
> >>> Subject: Re: [PATCH] pinctrl: at91: add the config GPIO_OUTPUT_x
> >>>
> >>>
> >>> On Mar 5, 2014, at 9:53 AM, Wenyou Yang <wenyou.yang@xxxxxxxxx>
> wrote:
> >>>
> >>>> In order to support the pinctrl sleep state.
> >>>
> >>> As I said before NACK
> >>>
> >>> this is not the job of the pinctrl to describe gpio output or input
> >>> state
> >> But according to what said in the section "GPIO mode pitfalls" of
> >> Documentation/pinctrl.txt.
> >> It should be handle by the pinctrl.
> >>
> >> If not, to deal with the sleep state will be very complicated.
> >> Muxing the pins for FUNCTION to enable peripheral, then twist them
> >> over to GPIO mode and use gpio_direction_output() to drive it HIGH or
> >> LOW during sleep.
> >>
> >> --->8 ------------
> >> The solution is to not think that what the datasheet calls "GPIO
> mode"
> >> has to be handled by the <linux/gpio.h> interface. Instead view this
> >> as a certain pin config setting. Look in e.g. <linux/pinctrl/pinconf-
> >> generic.h> and you find this in the documentation:
> >>
> >> PIN_CONFIG_OUTPUT: this will configure the pin in output, use
> argument
> >> 1 to indicate high level, argument 0 to indicate low level.
> >>
> >> So it is perfectly possible to push a pin into "GPIO mode" and drive
> >> the line low as part of the usual pin control map.
> >> ---<8 ------------
> >
> > Do you have any feedback?
>
> Here the issue is that you do drive the gpio and use as a gpio
>
> which means you request it as a GPIO so after you can not reswitch it to
> alternative function and the gpio is already requested as alternative
> function
>
> So basically you mess-up with the gpio API and pinctrl API by bypassing
> both

But I don't agree with you.

As I known, in mainline the other SoC vendors provide such function, configure the gpio mode with output config by pinctrl.

For example, ST. nomadisk.
You can see it in the function: nmk_pin_config_set() of the file, pinctrl-nomadik.c.
It provides GPIO mode and OUTPUT config.

This is a good solution, as what said in Documentation/pinctrl.txt,

it is perfectly possible to push a pin into "GPIO mode" and drive the line low as part of the usual pin control map.

Best Regards,
Wenyou Yang
>
> Best Regards,
> J.
>
> >
> > Thanks,
> > Wenyou Yang
> >
> >>
> >>>
> >>> Best Regards,
> >>> J.
> >>>>
> >>>> Signed-off-by: Wenyou Yang <wenyou.yang@xxxxxxxxx>
> >>>> ---
> >>>> Hi Linus,
> >>>>
> >>>> The patch is based on branch: for-next
> >>>> git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl
> >>>>
> >>>> Best Regards,
> >>>> Wenyou Yang
> >>>>
> >>>> drivers/pinctrl/pinctrl-at91.c | 31
> >>> +++++++++++++++++++++++++++++++
> >>>> include/dt-bindings/pinctrl/at91.h | 2 ++
> >>>> 2 files changed, 33 insertions(+)
> >>>>
> >>>> diff --git a/drivers/pinctrl/pinctrl-at91.c
> >>>> b/drivers/pinctrl/pinctrl-at91.c index 5d24aae..fc51e59 100644
> >>>> --- a/drivers/pinctrl/pinctrl-at91.c
> >>>> +++ b/drivers/pinctrl/pinctrl-at91.c
> >>>> @@ -62,6 +62,8 @@ static int gpio_banks;
> >>>> #define DEGLITCH (1 << 2)
> >>>> #define PULL_DOWN (1 << 3)
> >>>> #define DIS_SCHMIT (1 << 4)
> >>>> +#define GPIO_OUTPUT_HIGH (1 << 5)
> >>>> +#define GPIO_OUTPUT_LOW (1 << 6)
> >>>> #define DEBOUNCE (1 << 16)
> >>>> #define DEBOUNCE_VAL_SHIFT 17
> >>>> #define DEBOUNCE_VAL (0x3fff << DEBOUNCE_VAL_SHIFT)
> >>>> @@ -152,12 +154,15 @@ struct at91_pinctrl_mux_ops {
> >>>> void (*set_pulldown)(void __iomem *pio, unsigned mask, bool is_on);
> >>>> bool (*get_schmitt_trig)(void __iomem *pio, unsigned pin);
> >>>> void (*disable_schmitt_trig)(void __iomem *pio, unsigned mask);
> >>>> + bool (*get_gpio_output)(void __iomem *pio, unsigned mask);
> >>>> + void (*set_gpio_output)(void __iomem *pio, unsigned mask,
> bool
> >>>> +is_high);
> >>>> /* irq */
> >>>> int (*irq_type)(struct irq_data *d, unsigned type); };
> >>>>
> >>>> static int gpio_irq_type(struct irq_data *d, unsigned type); static
> >>>> int alt_gpio_irq_type(struct irq_data *d, unsigned type);
> >>>> +static void at91_mux_gpio_enable(void __iomem *pio, unsigned mask,
> >>>> +bool input);
> >>>>
> >>>> struct at91_pinctrl {
> >>>> struct device *dev;
> >>>> @@ -472,6 +477,20 @@ static bool
> >>>> at91_mux_pio3_get_schmitt_trig(void
> >>> __iomem *pio, unsigned pin)
> >>>> return (__raw_readl(pio + PIO_SCHMITT) >> pin) & 0x1; }
> >>>>
> >>>> +static bool at91_mux_pio3_get_gpio_output(void __iomem *pio,
> >>>> +unsigned
> >>>> +pin) {
> >>>> + return (__raw_readl(pio + PIO_ODSR) >> pin) & 0x1; }
> >>>> +
> >>>> +static void at91_mux_pio3_set_gpio_output(void __iomem *pio,
> >>>> + unsigned mask,
> >>>> + bool is_high)
> >>>> +{
> >>>> + at91_mux_gpio_enable(pio, mask, 0);
> >>>> + writel_relaxed(mask, pio + (is_high ? PIO_SODR : PIO_CODR)); }
> >>>> +
> >>>> +
> >>>> static struct at91_pinctrl_mux_ops at91rm9200_ops = {
> >>>> .get_periph = at91_mux_get_periph,
> >>>> .mux_A_periph = at91_mux_set_A_periph,
> >>>> @@ -495,6 +514,8 @@ static struct at91_pinctrl_mux_ops
> >>>> at91sam9x5_ops
> >>> = {
> >>>> .set_pulldown = at91_mux_pio3_set_pulldown,
> >>>> .get_schmitt_trig = at91_mux_pio3_get_schmitt_trig,
> >>>> .disable_schmitt_trig = at91_mux_pio3_disable_schmitt_trig,
> >>>> + .get_gpio_output = at91_mux_pio3_get_gpio_output,
> >>>> + .set_gpio_output = at91_mux_pio3_set_gpio_output,
> >>>> .irq_type = alt_gpio_irq_type,
> >>>> };
> >>>>
> >>>> @@ -741,6 +762,10 @@ static int at91_pinconf_get(struct pinctrl_dev
> >>> *pctldev,
> >>>> *config |= PULL_DOWN;
> >>>> if (info->ops->get_schmitt_trig &&
> >>>> info->ops->get_schmitt_trig(pio,
> >>> pin))
> >>>> *config |= DIS_SCHMIT;
> >>>> + if (info->ops->get_gpio_output) {
> >>>> + *config |= info->ops->get_gpio_output(pio, pin) ?
> >>>> + GPIO_OUTPUT_HIGH : GPIO_OUTPUT_LOW;
> >>>> + }
> >>>>
> >>>> return 0;
> >>>> }
> >>>> @@ -778,6 +803,12 @@ static int at91_pinconf_set(struct pinctrl_dev
> >>> *pctldev,
> >>>> info->ops->set_pulldown(pio, mask, config & PULL_DOWN);
> >>>> if (info->ops->disable_schmitt_trig && config & DIS_SCHMIT)
> >>>> info->ops->disable_schmitt_trig(pio, mask);
> >>>> + if (info->ops->set_gpio_output) {
> >>>> + if (config & GPIO_OUTPUT_HIGH)
> >>>> + info->ops->set_gpio_output(pio, mask, 1);
> >>>> + if (config & GPIO_OUTPUT_LOW)
> >>>> + info->ops->set_gpio_output(pio, mask, 0);
> >>>> + };
> >>>>
> >>>> } /* for each config */
> >>>>
> >>>> diff --git a/include/dt-bindings/pinctrl/at91.h
> >>>> b/include/dt-bindings/pinctrl/at91.h
> >>>> index 0fee6ff..e799268 100644
> >>>> --- a/include/dt-bindings/pinctrl/at91.h
> >>>> +++ b/include/dt-bindings/pinctrl/at91.h
> >>>> @@ -15,6 +15,8 @@
> >>>> #define AT91_PINCTRL_DEGLITCH (1 << 2)
> >>>> #define AT91_PINCTRL_PULL_DOWN (1 << 3)
> >>>> #define AT91_PINCTRL_DIS_SCHMIT (1 << 4)
> >>>> +#define AT91_PINCTRL_OUTPUT_HIGH (1 << 5)
> >>>> +#define AT91_PINCTRL_OUTPUT_LOW (1 << 6)
> >>>> #define AT91_PINCTRL_DEBOUNCE (1 << 16)
> >>>> #define AT91_PINCTRL_DEBOUNCE_VAL(x) (x << 17)
> >>>>
> >>>> --
> >>>> 1.7.9.5
> >>>>
> >
> >
> > _______________________________________________
> > linux-arm-kernel mailing list
> > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

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Next message: Takashi Iwai: "Re: [PATCH] sound: sound_core: Reduce checkpatch noise"
Previous message: Takashi Iwai: "Re: [PATCH] Revert "ALSA: emu10k1: Fix warning: "CCR" redefined""
In reply to: Jean-Christophe PLAGNIOL-VILLARD: "Re: [PATCH] pinctrl: at91: add the config GPIO_OUTPUT_x"
Next in thread: Jean-Christophe PLAGNIOL-VILLARD: "Re: [PATCH] pinctrl: at91: add the config GPIO_OUTPUT_x"
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