[U-Boot] [PATCH v2 8/9] tegra: add SPI SLINK driver

[Stephen Warren <swarren@wwwdotorg.org>]

On 01/12/2013 09:56 AM, Simon Glass wrote:
> Hi,
> 
> On Sat, Jan 12, 2013 at 1:07 AM, Allen Martin <amartin@nvidia.com> wrote:
>> Add driver for tegra SPI "SLINK" style driver.  This controller is
>> similar to the tegra20 SPI "SFLASH" controller.  The difference is
>> that the SLINK controller is a genernal purpose SPI controller and the
>> SFLASH controller is special purpose and can only talk to FLASH
>> devices.  In addition there are potentially many instances of an SLINK
>> controller on tegra and only a single instance of SFLASH.  Tegra20 is
>> currently ths only version of tegra that instantiates an SFLASH
>> controller.
>>
>> This driver supports basic PIO mode of operation and is configurable
>> (CONFIG_OF_CONTROL) to be driven off devicetree bindings.  Up to 4
>> devices per controller may be attached, although typically only a
>> single chip select line is exposed from tegra per controller so in
>> reality this is usually limited to 1.
>>
>> To enable this driver, use CONFIG_TEGRA_SLINK

>> diff --git a/drivers/spi/tegra_slink.c b/drivers/spi/tegra_slink.c

>> +#ifdef CONFIG_OF_CONTROL
> 
> You probably don't need this ifdef

If we did assume CONFIG_OF_CONTROL was on, then we could get rid of the
previous patch; all the device addresses would come from device tree, so
there would be no need to add them to any header file:-)

>> +void spi_init(void)
>> +{
>> +       int node = 0, i;
>> +       struct tegra_spi_ctrl *ctrl;
> 
> blank line here
> 
>> +       for (i = 0; i < CONFIG_TEGRA_SLINK_CTRLS; i++) {
>> +               ctrl = &spi_ctrls[i];
>> +#ifdef CONFIG_OF_CONTROL
>> +               node = fdtdec_next_compatible(gd->fdt_blob, node,
>> +                                             COMPAT_NVIDIA_TEGRA20_SLINK);
>> +               if (!node)
>> +                       break;
> 
> I think you should be using fdtdec_find_aliases_for_id() so that aliases work.

I strongly believe we shouldn't be using aliases for enumeration, which
is what fdtdec_find_aliases_for_id() does, IIRC. Instead, we should
enumerate all the devices in the correct fashion, and then apply aliases
as a separate step if they exists. Hence, I believe it's not correct to
use fdtdec_find_aliases_for_id() anywhere.