[linux-sunxi] [PATCH] pinctrl: sun4i: add spdif to pin description.

[Chen-Yu Tsai]

On Wed, Aug 12, 2015 at 5:13 PM, Code Kipper <codekipper at gmail.com> wrote:
> On 12 August 2015 at 10:34, Hans de Goede <hdegoede at redhat.com> wrote:
>>
>> Hi,
>>
>>
>> On 12-08-15 07:31, Code Kipper wrote:
>>>
>>> On 11 August 2015 at 18:48, Chen-Yu Tsai <wens at csie.org> wrote:
>>>
>>>> On Wed, Aug 12, 2015 at 12:19 AM,  <codekipper at gmail.com> wrote:
>>>>>
>>>>> From: Marcus Cooper <codekipper at gmail.com>
>>>>>
>>>>> Signed-off-by: Marcus Cooper <codekipper at gmail.com>
>>>>> ---
>>>>>   drivers/pinctrl/sunxi/pinctrl-sun4i-a10.c | 9 ++++++---
>>>>>   1 file changed, 6 insertions(+), 3 deletions(-)
>>>>>
>>>>> diff --git a/drivers/pinctrl/sunxi/pinctrl-sun4i-a10.c
>>>>
>>>> b/drivers/pinctrl/sunxi/pinctrl-sun4i-a10.c
>>>>>
>>>>> index 7376a97..daf7dec 100644
>>>>> --- a/drivers/pinctrl/sunxi/pinctrl-sun4i-a10.c
>>>>> +++ b/drivers/pinctrl/sunxi/pinctrl-sun4i-a10.c
>>>>> @@ -135,7 +135,8 @@ static const struct sunxi_desc_pin sun4i_a10_pins[]
>>>>
>>>> = {
>>>>>
>>>>>          SUNXI_PIN(SUNXI_PINCTRL_PIN(B, 3),
>>>>>                    SUNXI_FUNCTION(0x0, "gpio_in"),
>>>>>                    SUNXI_FUNCTION(0x1, "gpio_out"),
>>>>> -                 SUNXI_FUNCTION(0x2, "ir0")),          /* TX */
>>>>> +                 SUNXI_FUNCTION(0x2, "ir0"),           /* TX */
>>>>> +                 SUNXI_FUNCTION(0x4, "spdif")),        /* MCLK */
>>>>>          SUNXI_PIN(SUNXI_PINCTRL_PIN(B, 4),
>>>>>                    SUNXI_FUNCTION(0x0, "gpio_in"),
>>>>>                    SUNXI_FUNCTION(0x1, "gpio_out"),
>>>>> @@ -176,11 +177,13 @@ static const struct sunxi_desc_pin
>>>>
>>>> sun4i_a10_pins[] = {
>>>>>
>>>>>                    SUNXI_FUNCTION(0x0, "gpio_in"),
>>>>>                    SUNXI_FUNCTION(0x1, "gpio_out"),
>>>>>                    SUNXI_FUNCTION(0x2, "i2s"),           /* DI */
>>>>> -                 SUNXI_FUNCTION(0x3, "ac97")),         /* DI */
>>>>> +                 SUNXI_FUNCTION(0x3, "ac97"),          /* DI */
>>>>> +                 SUNXI_FUNCTION(0x4, "spdif")),        /* DI */
>>>>>          SUNXI_PIN(SUNXI_PINCTRL_PIN(B, 13),
>>>>>                    SUNXI_FUNCTION(0x0, "gpio_in"),
>>>>>                    SUNXI_FUNCTION(0x1, "gpio_out"),
>>>>> -                 SUNXI_FUNCTION(0x2, "spi2")),         /* CS1 */
>>>>> +                 SUNXI_FUNCTION(0x2, "spi2"),          /* CS1 */
>>>>> +                 SUNXI_FUNCTION(0x4, "spdif")),        /* DO */
>>>>
>>>>
>>>> The datasheet and manual list them as NC or Reserved. Maybe mention how
>>>> you knew
>>>> they were available?
>>>>
>>> Not sure if this deserves to be in the commit message but I can
>>> definitely
>>> put together a covering letter with links etc.
>>
>>
>> I dear to say it belongs right there in the source code, use a multi-line
>> comment above the SUNXI_FUNCTION(0x4, "spdif")) to explain where the mux
>> info comes from. someday sooner or later someone is going to compare the
>> kernel mux table to the datasheet and think "huh, that is not right",
>> that person will be saved an immense amount of time by simply having a
>> comment there.
>
> Good point I was thinking something along the lines of this
> /*
>  * The SPDIF block is not referenced at all in the A10 user
>  * manual. However it is described in the code leaked and the
>  * pin descriptions are declared in the A20 user manual which
>  * is pin compatible with this device.
>  */
> Thing is do I add this above every spdif pin, the first change(MCLK) or the
> pin most likely to be used(SPDIF DO)?

I'd say put it before the first pin, and then reference it (like
"undocumented, see the comment for pin P??? above", for the rest.

ChenYu

> Thanks,
> CK
>>
>>
>> And do NOT say that this will not happen, because I've already done
>> such a comparison once in the past.
>>
>> Regards,
>>
>> Hans
>
>