[U-Boot] [PATCH] Tegra30: Cardhu: Add pad config tables/code based on pinmux code

[Stephen Warren <swarren@wwwdotorg.org>]

On 03/07/2013 02:13 PM, Tom Warren wrote:
> Stephen,
> 
> On Thu, Mar 7, 2013 at 1:27 PM, Stephen Warren <swarren@wwwdotorg.org> wrote:
>> On 03/06/2013 04:51 PM, Tom Warren wrote:
>>> Pad config registers exist in APB_MISC_GP space, and control slew
>>> rate, drive strengh, schmidt, high-speed, and low-power modes for
>>> all of the pingroups in Tegra30. This builds off of the pinmux
>>> way of constructing init tables to configure select pads (SDIOCFG,
>>> for instance) during pinmux_init().
>>>
>>> Currently, only SDIO1CFG is changed as per the TRM to work with
>>> the SD-card slot on Cardhu.
...
>> I didn't quite get why there wasn't an SDIO3 entry in that table, since
>> the original pinmux_sdio_pad_cfg() set up both SDIO1 and SDIO3 pin
>> groups, and SDIO3 appears to be used on Cardhu for SDIO-based WiFi.
> 
> The previous code did check for SDMMC1 or SDMMC3, but on Cardhu,
> SDMMC1 is called out in the dts file, and SDMMC3 isn't (you had said
> earlier when reviewing some Ventana changes that leaving out a SDIO
> WIFI node was ok as U-Boot wouldn't be using it, so I didn't add it to
> Cardhu). So the old code would only have called the pad init code for
> SDMMC1 and SDMMC4, and SDMMC4 would have been rejected since it's not
> SDIO.  So I only added SDIO1 to the table.  I can add an entry for
> SDIO3 (even if it's not in the dts file for Cardhu), since it does no
> harm to set those pad cfg registers as per the TRM (I assume the TRM
> is calling out cal numbers that will work with both an SD-card slot
> and a WIFI device?).
> 
> Let me know if you'd like to see either the WIFI node added to the
> Cardhu DT file, or the SDIO3 entry added to the cardhu_padctrl table,
> or both.

Ah OK, now I understand. This is fine for now; we can add the extra
table entries if we need them. The kernel does set them up for its own
use of WiFi.