[U-Boot] [PATCH] tegra20: tamonten: Fix the early gpio init

[Stephen Warren]

On 10/02/2014 01:05 PM, Simon Glass wrote:
> Hi Alban,
>
> On 2 October 2014 10:12, Alban Bedel <alban.bedel at avionic-design.de> wrote:
>>
>> On Thu, 02 Oct 2014 09:42:18 -0600
>> Stephen Warren <swarren at wwwdotorg.org> wrote:
>>
>>> On 10/02/2014 09:14 AM, Alban Bedel wrote:
>>>> To set gpio during the early init we now need to use
>>>> tegra_spl_gpio_direction_output(), copied from seaboard.
>>>>
>>>> Change-Id: Id0aadb17a71b78e75e8c3f8de374102b3eab767b
>>>
>>> That shouldn't be present on upstream patches.
>>
>> Sorry about this.
>
> If you use patman it will take these out for you automatically without
> you having to think about it.
>
>>
>>
>>>> Signed-off-by: Alban Bedel <alban.bedel at avionic-design.de>
>>>> ---
>>>>    board/avionic-design/common/tamonten.c | 4 +++-
>>>>    1 file changed, 3 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/board/avionic-design/common/tamonten.c b/board/avionic-design/common/tamonten.c
>>>> index 9c86779..ea2425a 100644
>>>> --- a/board/avionic-design/common/tamonten.c
>>>> +++ b/board/avionic-design/common/tamonten.c
>>>> @@ -23,8 +23,10 @@
>>>>    #ifdef CONFIG_BOARD_EARLY_INIT_F
>>>>    void gpio_early_init(void)
>>>>    {
>>>> +#ifndef CONFIG_SPL_BUILD
>>>>      gpio_request(GPIO_PI4, NULL);
>>>> -   gpio_direction_output(GPIO_PI4, 1);
>>>> +#endif
>>>> +   tegra_spl_gpio_direction_output(GPIO_PI4, 1);
>>>>    }
>>>
>>> Surely you only want to call tegra_spl_*() from SPL, and not from
>>> non-SPL code? In other words, don't you need something more like:
>>>
>>> #ifdef CONFIG_SPL_BUILD
>>>        tegra_spl_gpio_direction_output(GPIO_PI4, 1);
>>> #else
>>>        gpio_request(GPIO_PI4, NULL);
>>>        gpio_direction_output(GPIO_PI4, 1);
>>> #endif
>>
>> Sadly not, at this point the gpio driver isn't available yet, that's
>> why one need to use tegra_spl_gpio_direction_output(). As mentioned in
>> the commit log I copied this from seaboard, assuming it would be
>> correct.
>>
>> AFAICT the gpio_request() could be removed too, it doesn't work at this
>> point anyway.
>
> This is a temporary measure until the SPL series is applied to dm/next
> at least (I expect sometime this month). While driver model is
> available before relocation, the Tegra GPIO driver is not marked in
> the device tree with "u-boot,dm-pre-reloc", so is not available this
> early. Device tree additions give Stephen a headache, and I decided it
> was better for it not to work for now, and just use the SPL function.
>
> There are three stages to consider:
>
> 1. SPL
> 2. U-Boot, before relocation
> 3. U-Boot, after relocation
>
> At present, driver model does not support 1 (see dm/spl-working for
> patches if you want to see this). It supports 2 but only for drivers
> marked pre-relocation (except serial, for which a hack forces the
> console to be bound and used in the device tree case without the
> u-boot,dm-pre-reloc marker). It supports 3 fully.

That's roughly what I expected. Given that, I fail to see why the 
following wouldn't work then:

 >>> #ifdef CONFIG_SPL_BUILD
 >>>        tegra_spl_gpio_direction_output(GPIO_PI4, 1);
 >>> #else
 >>>        gpio_request(GPIO_PI4, NULL);
 >>>        gpio_direction_output(GPIO_PI4, 1);
 >>> #endif

(or have just 1 of those two ifdef branches; presumably the GPIO only 
needs to be initialized in one place not both?)