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

From: Jean-Christophe PLAGNIOL-VILLARD
Date: Tue Mar 11 2014 - 00:35:32 EST

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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

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: Alexei Starovoitov: "[PATCH v9 net-next 0/3] filter: add Extended BPF interpreter and converter, seccomp"
Previous message: Erico Nunes: "[PATCH] mtd: nand: fix mention to CONFIG_MTD_NAND_ECC_BCH"
In reply to: Yang, Wenyou: "RE: [PATCH] pinctrl: at91: add the config GPIO_OUTPUT_x"
Next in thread: Yang, Wenyou: "RE: [PATCH] pinctrl: at91: add the config GPIO_OUTPUT_x"
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