pinctrl: sunxi: Honor GPIO output initial vaules
diff mbox

Message ID 1389711021-16430-1-git-send-email-wens@csie.org
State New, archived
Headers show

Commit Message

Chen-Yu Tsai (Moxa) Jan. 14, 2014, 2:50 p.m. UTC
Some GPIO users, such as fixed-regulator, request GPIO output with
initial value of 1. This was ignored by sunxi driver.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
---
 drivers/pinctrl/pinctrl-sunxi.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

Comments

Chen-Yu Tsai (Moxa) Jan. 15, 2014, 8:21 a.m. UTC | #1
Hi,

On Wed, Jan 15, 2014 at 8:37 AM, Ma Haijun <mahaijuns@gmail.com> wrote:
> Hi,
>
> I think it is better to set the output value first to avoid glitch.

If I understand the user manual correctly, setting the output value
before changing the pin to output function first will have no effect.

And it is not possible to set the function and the value at the same
time, as they are in different registers.


Cheers,
ChenYu

> Regards,
>
> Ma
>
>> -----Original Message-----
>> From: linux-sunxi@googlegroups.com [mailto:linux-sunxi@googlegroups.com]
>> On Behalf Of Chen-Yu Tsai
>> Sent: Tuesday, January 14, 2014 10:50 PM
>> To: Maxime Ripard
>> Cc: Chen-Yu Tsai; linux-arm-kernel; linux-sunxi; Linus Walleij
>> Subject: [linux-sunxi] [PATCH] pinctrl: sunxi: Honor GPIO output initial
> vaules
>>
>> Some GPIO users, such as fixed-regulator, request GPIO output with initial
>> value of 1. This was ignored by sunxi driver.
>>
>> Signed-off-by: Chen-Yu Tsai <wens@csie.org>
>> ---
>>  drivers/pinctrl/pinctrl-sunxi.c | 17 +++++++++++------
>>  1 file changed, 11 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/pinctrl/pinctrl-sunxi.c
> b/drivers/pinctrl/pinctrl-sunxi.c index
>> 119d2dd..fc72d10 100644
>> --- a/drivers/pinctrl/pinctrl-sunxi.c
>> +++ b/drivers/pinctrl/pinctrl-sunxi.c
>> @@ -469,12 +469,6 @@ static int sunxi_pinctrl_gpio_get(struct gpio_chip
>> *chip, unsigned offset)
>>       return val;
>>  }
>>
>> -static int sunxi_pinctrl_gpio_direction_output(struct gpio_chip *chip,
>> -                                     unsigned offset, int value)
>> -{
>> -     return pinctrl_gpio_direction_output(chip->base + offset);
>> -}
>> -
>>  static void sunxi_pinctrl_gpio_set(struct gpio_chip *chip,
>>                               unsigned offset, int value)
>>  {
>> @@ -498,6 +492,17 @@ static void sunxi_pinctrl_gpio_set(struct gpio_chip
>> *chip,
>>       spin_unlock_irqrestore(&pctl->lock, flags);  }
>>
>> +static int sunxi_pinctrl_gpio_direction_output(struct gpio_chip *chip,
>> +                                     unsigned offset, int value)
>> +{
>> +     int ret = pinctrl_gpio_direction_output(chip->base + offset);
>> +
>> +     if (ret == 0)
>> +             sunxi_pinctrl_gpio_set(chip, offset, value);
>> +
>> +     return ret;
>> +}
>> +
>>  static int sunxi_pinctrl_gpio_of_xlate(struct gpio_chip *gc,
>>                               const struct of_phandle_args *gpiospec,
>>                               u32 *flags)
>> --
>> 1.8.5.2
>>
Maxime Ripard Jan. 15, 2014, 10:02 a.m. UTC | #2
Hi Chen-Yu,

Nice catch :)

On Wed, Jan 15, 2014 at 04:21:12PM +0800, Chen-Yu Tsai wrote:
> Hi,
> 
> On Wed, Jan 15, 2014 at 8:37 AM, Ma Haijun <mahaijuns@gmail.com> wrote:
> > Hi,
> >
> > I think it is better to set the output value first to avoid glitch.
> 
> If I understand the user manual correctly, setting the output value
> before changing the pin to output function first will have no effect.

I just tested it on my A31, and it is working as expected (the output
value isn't output until the direction is changed).

It would be great if you could test this as well on your device, and
change it like suggested.

Thanks!
Maxime
Chen-Yu Tsai (Moxa) Jan. 15, 2014, 1:10 p.m. UTC | #3
Hi,

On Wed, Jan 15, 2014 at 6:02 PM, Maxime Ripard
<maxime.ripard@free-electrons.com> wrote:
> Hi Chen-Yu,
>
> Nice catch :)
>
> On Wed, Jan 15, 2014 at 04:21:12PM +0800, Chen-Yu Tsai wrote:
>> Hi,
>>
>> On Wed, Jan 15, 2014 at 8:37 AM, Ma Haijun <mahaijuns@gmail.com> wrote:
>> > Hi,
>> >
>> > I think it is better to set the output value first to avoid glitch.
>>
>> If I understand the user manual correctly, setting the output value
>> before changing the pin to output function first will have no effect.
>
> I just tested it on my A31, and it is working as expected (the output
> value isn't output until the direction is changed).
>
> It would be great if you could test this as well on your device, and
> change it like suggested.

Tested on A20, works as you described. Output value is queued and changed
when pin function is changed to output.

I will rearrange the function calls and resend.


Cheers
ChenYu

Patch
diff mbox

diff --git a/drivers/pinctrl/pinctrl-sunxi.c b/drivers/pinctrl/pinctrl-sunxi.c
index 119d2dd..fc72d10 100644
--- a/drivers/pinctrl/pinctrl-sunxi.c
+++ b/drivers/pinctrl/pinctrl-sunxi.c
@@ -469,12 +469,6 @@  static int sunxi_pinctrl_gpio_get(struct gpio_chip *chip, unsigned offset)
 	return val;
 }
 
-static int sunxi_pinctrl_gpio_direction_output(struct gpio_chip *chip,
-					unsigned offset, int value)
-{
-	return pinctrl_gpio_direction_output(chip->base + offset);
-}
-
 static void sunxi_pinctrl_gpio_set(struct gpio_chip *chip,
 				unsigned offset, int value)
 {
@@ -498,6 +492,17 @@  static void sunxi_pinctrl_gpio_set(struct gpio_chip *chip,
 	spin_unlock_irqrestore(&pctl->lock, flags);
 }
 
+static int sunxi_pinctrl_gpio_direction_output(struct gpio_chip *chip,
+					unsigned offset, int value)
+{
+	int ret = pinctrl_gpio_direction_output(chip->base + offset);
+
+	if (ret == 0)
+		sunxi_pinctrl_gpio_set(chip, offset, value);
+
+	return ret;
+}
+
 static int sunxi_pinctrl_gpio_of_xlate(struct gpio_chip *gc,
 				const struct of_phandle_args *gpiospec,
 				u32 *flags)