[PATCH] mmc: sdhci-of-at91: Support external regulators

[Ulf Hansson]

+ stable

On 14 March 2017 at 14:06, Ludovic Desroches
<ludovic.desroches at microchip.com> wrote:
> On Thu, Mar 09, 2017 at 04:18:20PM +0100, Romain Izard wrote:
>> The SDHCI controller in the SAMA5D2 chip requires a valid voltage set
>> in the power control register, otherwise commands will fail with a
>> timeout error.
>>
>> When using the regulator framework to specify the regulator used by the
>> mmc device, the voltage is not configured, and it is not possible to use
>> the connected device.
>>
>> Implement a custom 'set_power' function for this specific hardware, that
>> configures the voltage in the register in all cases.
>>
>> Signed-off-by: Romain Izard <romain.izard.pro at gmail.com>

Thanks, applied for fixes and by correcting a "contoller" to
"controller" as pointed out by Ludovic.

Kind regards
Uffe

>
> Cc: stable at vger.kernel.org #4.9+
>
> Can be added since sdhci_set_power_noreg was introduced in 4.9.
>
>> ---
>>  drivers/mmc/host/sdhci-of-at91.c | 19 +++++++++++++++++++
>>  1 file changed, 19 insertions(+)
>>
>> diff --git a/drivers/mmc/host/sdhci-of-at91.c b/drivers/mmc/host/sdhci-of-at91.c
>> index 2f9ad213377a..291a74955a4c 100644
>> --- a/drivers/mmc/host/sdhci-of-at91.c
>> +++ b/drivers/mmc/host/sdhci-of-at91.c
>> @@ -85,11 +85,30 @@ static void sdhci_at91_set_clock(struct sdhci_host *host, unsigned int clock)
>>       sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
>>  }
>>
>> +/*
>> + * In this specific implementation of the SDHCI contoller, the power register
>> + * needs to have a valid voltage set even when the power supply is managed by
>> + * an external regulator.
>> + */
>> +static void sdhci_at91_set_power(struct sdhci_host *host, unsigned char mode,
>> +                  unsigned short vdd)
>> +{
>> +     if (!IS_ERR(host->mmc->supply.vmmc)) {
>> +             struct mmc_host *mmc = host->mmc;
>> +
>> +             spin_unlock_irq(&host->lock);
>> +             mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, vdd);
>> +             spin_lock_irq(&host->lock);
>> +     }
>> +     sdhci_set_power_noreg(host, mode, vdd);
>> +}
>> +
>>  static const struct sdhci_ops sdhci_at91_sama5d2_ops = {
>>       .set_clock              = sdhci_at91_set_clock,
>>       .set_bus_width          = sdhci_set_bus_width,
>>       .reset                  = sdhci_reset,
>>       .set_uhs_signaling      = sdhci_set_uhs_signaling,
>> +     .set_power              = sdhci_at91_set_power,
>>  };
>>
>>  static const struct sdhci_pltfm_data soc_data_sama5d2 = {
>> --
>> 2.9.3
>>
>> --
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