[PATCH] mmc: msm_sdhci: enable vqmmc at probe if available

[Neil Armstrong]

On 24/10/2024 15:11, Caleb Connolly wrote:
> Hi Neil,
> 
> On 16/10/2024 11:17, Neil Armstrong wrote:
>> On earlier platforms, the vqmmc regulator was enabled by the
>> previous bootloader, but on the newest (SM8650) it's not
>> and we need vqmmc to be enabled in order to have the card
>> to respond.
> 
> Isn't/shouldn't this be handled in mmc_power_init() ?

So, yes and no, the device_get_supply_regulator(vqmmc-supply) in mmc_power_init is
done to be used by sdhci_set_voltage() but .... but ... Qualcomm doesn't use
MMC_SIGNAL_VOLTAGE_330 but MMC_SIGNAL_VOLTAGE_300 which is implemented in Linux
but not in Uboot, so it would require a significant mmc/sdhci driver update
but since we 're not even far from supporting any card state requiring
MMC_SIGNAL_VOLTAGE_180 we don't even declare the sdhci_ops and neither
any of the config_dll/set_enhanced_strobe/execute_tuning so in our current
case we just need to enable vqmmc.

Neil
> 
> Kind regards,
>>
>> Signed-off-by: Neil Armstrong <neil.armstrong at linaro.org>
>> ---
>>   drivers/mmc/msm_sdhci.c | 12 ++++++++++++
>>   1 file changed, 12 insertions(+)
>>
>> diff --git a/drivers/mmc/msm_sdhci.c b/drivers/mmc/msm_sdhci.c
>> index 4e5c932c071..27bb7052fca 100644
>> --- a/drivers/mmc/msm_sdhci.c
>> +++ b/drivers/mmc/msm_sdhci.c
>> @@ -15,6 +15,7 @@
>>   #include <asm/global_data.h>
>>   #include <asm/io.h>
>>   #include <linux/bitops.h>
>> +#include <power/regulator.h>
>>   /* Non-standard registers needed for SDHCI startup */
>>   #define SDCC_MCI_POWER   0x0
>> @@ -43,6 +44,7 @@ struct msm_sdhc {
>>       struct sdhci_host host;
>>       void *base;
>>       struct clk_bulk clks;
>> +    struct udevice *vqmmc;
>>   };
>>   struct msm_sdhc_variant_info {
>> @@ -163,6 +165,16 @@ static int msm_sdc_probe(struct udevice *dev)
>>       if (ret)
>>           return ret;
>> +    /* Get the vqmmc regulator and enable it if available */
>> +    device_get_supply_regulator(dev, "vqmmc-supply", &prv->vqmmc);
>> +    if (prv->vqmmc) {
>> +        ret = regulator_set_enable_if_allowed(prv->vqmmc, true);
>> +        if (ret) {
>> +            printf("Failed to enable the VQMMC regulator\n");
>> +            return ret;
>> +        }
>> +    }
>> +
>>       var_info = (void *)dev_get_driver_data(dev);
>>       if (!var_info->mci_removed) {
>>           ret = msm_sdc_mci_init(prv);
>>
>> ---
>> base-commit: d5cab0d6adc26ec1bbd45c2fed101184d04454ae
>> change-id: 20241016-topic-sm8x50-mmc-vqmmc-b7cf8176ec51
>>
>> Best regards,
>