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Date: Thu, 13 Mar 2014 07:27:42 +0100
From: Boris BREZILLON <b.brezillon.dev@...il.com>
To: "Yang, Wenyou" <Wenyou.Yang@...el.com>,
Jean-Christophe PLAGNIOL-VILLARD <plagnioj@...osoft.com>,
"b.brezillon@...rkiz.com" <b.brezillon@...rkiz.com>,
"linus.walleij@...aro.org" <linus.walleij@...aro.org>
CC: "mark.rutland@....com" <mark.rutland@....com>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
"pawel.moll@....com" <pawel.moll@....com>,
"ijc+devicetree@...lion.org.uk" <ijc+devicetree@...lion.org.uk>,
Linux Kernel list <linux-kernel@...r.kernel.org>,
"robh+dt@...nel.org" <robh+dt@...nel.org>,
"galak@...eaurora.org" <galak@...eaurora.org>,
"<linux-arm-kernel@...ts.infradead.org> mailing list"
<linux-arm-kernel@...ts.infradead.org>,
"Lin, JM" <JM.Lin@...el.com>
Subject: Re: [PATCH] pinctrl: at91: add the config GPIO_OUTPUT_x
Le 13/03/2014 07:00, Yang, Wenyou a écrit :
> Hi JC,
>
>> -----Original Message-----
>> From: Jean-Christophe PLAGNIOL-VILLARD [mailto:plagnioj@...osoft.com]
>> Sent: Tuesday, March 11, 2014 7:14 PM
>> To: Yang, Wenyou
>> Cc: Jean-Christophe PLAGNIOL-VILLARD; mark.rutland@....com;
>> devicetree@...r.kernel.org; pawel.moll@....com;
>> ijc+devicetree@...lion.org.uk; linus.walleij@...aro.org; Linux Kernel
>> list; b.brezillon@...rkiz.com; robh+dt@...nel.org; galak@...eaurora.org;
>> <linux-arm-kernel@...ts.infradead.org> mailing list; Lin, JM
>> Subject: Re: [PATCH] pinctrl: at91: add the config GPIO_OUTPUT_x
>>
>>
>> On Mar 11, 2014, at 2:54 PM, Yang, Wenyou <Wenyou.Yang@...el.com> wrote:
>>
>>>
>>>> -----Original Message-----
>>>> From: Jean-Christophe PLAGNIOL-VILLARD [mailto:plagnioj@...osoft.com]
>>>> Sent: Tuesday, March 11, 2014 12:16 PM
>>>> To: Yang, Wenyou
>>>> Cc: Jean-Christophe PLAGNIOL-VILLARD; mark.rutland@....com;
>>>> devicetree@...r.kernel.org; pawel.moll@....com;
>>>> ijc+devicetree@...lion.org.uk; linus.walleij@...aro.org; Linux Kernel
>>>> list; b.brezillon@...rkiz.com; robh+dt@...nel.org;
>>>> galak@...eaurora.org; <linux-arm-kernel@...ts.infradead.org> 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@...el.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@...aro.org; b.brezillon@...rkiz.com; <linux-arm-
>>>>>> kernel@...ts.infradead.org> mailing list; Linux Kernel list;
>>>>>> devicetree@...r.kernel.org; robh+dt@...nel.org; pawel.moll@....com;
>>>>>> mark.rutland@....com; ijc+devicetree@...lion.org.uk;
>>>>>> galak@...eaurora.org
>>>>>> Subject: RE: [PATCH] pinctrl: at91: add the config GPIO_OUTPUT_x
>>>>>>
>>>>>> Hi JC,
>>>>>>
>>>>>>> -----Original Message-----
>>>>>>> From: Jean-Christophe PLAGNIOL-VILLARD
>>>>>>> [mailto:plagnioj@...osoft.com]
>>>>>>> Sent: Wednesday, March 05, 2014 12:58 PM
>>>>>>> To: Yang, Wenyou
>>>>>>> Cc: Jean-Christophe PLAGNIOL-VILLARD; linus.walleij@...aro.org;
>>>>>>> b.brezillon@...rkiz.com; <linux-arm-kernel@...ts.infradead.org>
>>>>>>> mailing list; Linux Kernel list; devicetree@...r.kernel.org;
>>>>>>> robh+dt@...nel.org; pawel.moll@....com; mark.rutland@....com;
>>>>>>> ijc+devicetree@...lion.org.uk; galak@...eaurora.org
>>>>>>> Subject: Re: [PATCH] pinctrl: at91: add the config GPIO_OUTPUT_x
>>>>>>>
>>>>>>>
>>>>>>> On Mar 5, 2014, at 9:53 AM, Wenyou Yang <wenyou.yang@...el.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
>>> 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.
>> This is simple if we use gpio mode as pinctrl tomorrow we will see gpio
>> configuration in pinctrl such as chip reset, default led state etc...
>>
>> The pinctrl is not here to control a *GPIO* but to describe the
>> configuration of pin.
> What you said is the usual use case.
>
> But, in the Power Management scenario, there are the following requirements to meet:
> When running time, the pins are configured as the PERIPH functions by the pinctrl default state as usaul.
> When suspending to memory, the pins are configured as GPIO output low, output high or input by the pinctrl sleep state.
> When resuming from suspended, the pins are configured back as the PERIPH functions.
>
> I just found the same implementation by Boris which is better.
> http://lists.infradead.org/pipermail/linux-arm-kernel/2013-August/194975.html
>
> Boris, Could you have something to say?
Yes.
I still think the pinconf OUTPUT state is useful in some cases, and the
one you described is obviously one of these (I needed it for a different
reason : https://lkml.org/lkml/2013/8/28/203 which appeared to be a wrong
one).
But I'm not the pinctrl subsystem or the at91 pinctrl driver maintainer...
Linus, do you have an opinion on this feature ?
>>>>>>>> Signed-off-by: Wenyou Yang <wenyou.yang@...el.com>
>>>>>>>> ---
>>>>>>>> Hi Linus,
>>>>>>>>
>>>>>>>> The patch is based on branch: for-next
>>>>>>>> git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctr
>>>>>>>> l
>>>>>>>>
>>>>>>>> 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@...ts.infradead.org
>>>>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>
> Bes Regards,
> Wenyou Yang
>
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