[U-Boot] [PATCH 12/22] mmc: Enable signal voltage to be selected from mmc core

[Kishon Vijay Abraham I]

Hi Simon,

On Monday 15 May 2017 08:58 AM, Simon Glass wrote:
> Hi Jen-Jacques,
> 
> On 12 May 2017 at 12:16, Jean-Jacques Hiblot <jjhiblot at ti.com> wrote:
>> From: Kishon Vijay Abraham I <kishon at ti.com>
>>
>> Add a new function *mmc_set_signal_voltage* in mmc core
>> which can be used during mmc initialization to select the
>> signal voltage. Platform driver should use the set_ios
>> callback function to select the signal voltage.
>>
>> Signed-off-by: Kishon Vijay Abraham I <kishon at ti.com>
>> Signed-off-by: Jean-Jacques Hiblot <jjhiblot at ti.com>
>> ---
>>  drivers/mmc/mmc.c | 15 +++++++++++++++
>>  include/mmc.h     |  5 +++++
>>  2 files changed, 20 insertions(+)
>>
>> diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
>> index 2ae6f1c..10af81d 100644
>> --- a/drivers/mmc/mmc.c
>> +++ b/drivers/mmc/mmc.c
>> @@ -29,6 +29,7 @@ static const unsigned int sd_au_size[] = {
>>         SZ_4M / 512,    SZ_8M / 512,            (SZ_8M + SZ_4M) / 512,
>>         SZ_16M / 512,   (SZ_16M + SZ_8M) / 512, SZ_32M / 512,   SZ_64M / 512,
>>  };
>> +static int mmc_set_signal_voltage(struct mmc *mmc, uint signal_voltage);
>>
>>  #if CONFIG_IS_ENABLED(MMC_TINY)
>>  static struct mmc mmc_static;
>> @@ -1247,6 +1248,12 @@ struct mode_width_tuning {
>>         uint widths;
>>  };
>>
>> +static int mmc_set_signal_voltage(struct mmc *mmc, uint signal_voltage)
>> +{
>> +       mmc->signal_voltage = signal_voltage;
>> +       return mmc_set_ios(mmc);
>> +}
>> +
>>  static const struct mode_width_tuning sd_modes_by_pref[] = {
>>         {
>>                 .mode = SD_HS,
>> @@ -1935,6 +1942,14 @@ int mmc_start_init(struct mmc *mmc)
>>                 return err;
>>  #endif
>>         mmc->ddr_mode = 0;
>> +
>> +       /* First try to set 3.3V. If it fails set to 1.8V */
>> +       err = mmc_set_signal_voltage(mmc, MMC_SIGNAL_VOLTAGE_330);
>> +       if (err != 0)
>> +               err = mmc_set_signal_voltage(mmc, MMC_SIGNAL_VOLTAGE_180);
>> +       if (err != 0)
>> +               printf("failed to set signal voltage\n");
> 
> Return error?

Since other API's here like mmc_set_bus_width, mmc_set_clock wasn't returning
error, I didn't return error from mmc_set_signal_voltage too. Thought returning
error can be added as a separate patch later for all the APIs used here.

Thanks
Kishon