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

[Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>]

On Mar 11, 2014, at 9:28 AM, Yang, Wenyou <Wenyou.Yang@atmel.com> wrote:

> Hi JC,
> 
>> -----Original Message-----
>> From: Yang, Wenyou
>> Sent: Wednesday, March 05, 2014 1:32 PM
>> To: Jean-Christophe PLAGNIOL-VILLARD
>> Cc: linus.walleij@linaro.org; b.brezillon@overkiz.com; <linux-arm-
>> kernel@lists.infradead.org> mailing list; Linux Kernel list;
>> devicetree@vger.kernel.org; robh+dt@kernel.org; pawel.moll@arm.com;
>> mark.rutland@arm.com; ijc+devicetree@hellion.org.uk;
>> galak@codeaurora.org
>> Subject: RE: [PATCH] pinctrl: at91: add the config GPIO_OUTPUT_x
>> 
>> Hi JC,
>> 
>>> -----Original Message-----
>>> From: Jean-Christophe PLAGNIOL-VILLARD [mailto:plagnioj@jcrosoft.com]
>>> Sent: Wednesday, March 05, 2014 12:58 PM
>>> To: Yang, Wenyou
>>> Cc: Jean-Christophe PLAGNIOL-VILLARD; linus.walleij@linaro.org;
>>> b.brezillon@overkiz.com; <linux-arm-kernel@lists.infradead.org>
>>> mailing list; Linux Kernel list; devicetree@vger.kernel.org;
>>> robh+dt@kernel.org; pawel.moll@arm.com; mark.rutland@arm.com;
>>> ijc+devicetree@hellion.org.uk; galak@codeaurora.org
>>> Subject: Re: [PATCH] pinctrl: at91: add the config GPIO_OUTPUT_x
>>> 
>>> 
>>> On Mar 5, 2014, at 9:53 AM, Wenyou Yang <wenyou.yang@atmel.com> 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@atmel.com>
>>>> ---
>>>> 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
>>>> 
> 
> 
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