On 25/07/18 15:23, Vijay Viswanath wrote:
> Hi Adrian,
>
>
> On 7/25/2018 5:23 PM, Adrian Hunter wrote:
>> On 20/07/18 13:46, Vijay Viswanath wrote:
>>> Some controllers can have internal mechanism to inform the SW that it
>>> is ready for voltage switching. For such controllers, changing voltage
>>> before the HW is ready can result in various issues.
>>>
>>> During setup/cleanup of host, check whether regulator enable/disable
>>> was already done by platform driver.
>>>
>>> Signed-off-by: Vijay Viswanath <[email protected]>
>>> ---
>>> drivers/mmc/host/sdhci.c | 21 ++++++++++++++++-----
>>> 1 file changed, 16 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>>> index 1c828e0..494a1e2 100644
>>> --- a/drivers/mmc/host/sdhci.c
>>> +++ b/drivers/mmc/host/sdhci.c
>>> @@ -3472,6 +3472,7 @@ int sdhci_setup_host(struct sdhci_host *host)
>>> unsigned int override_timeout_clk;
>>> u32 max_clk;
>>> int ret;
>>> + bool enable_vqmmc = false;
>>> WARN_ON(host == NULL);
>>> if (host == NULL)
>>> @@ -3485,7 +3486,12 @@ int sdhci_setup_host(struct sdhci_host *host)
>>> * the host can take the appropriate action if regulators are not
>>> * available.
>>> */
>>> - ret = mmc_regulator_get_supply(mmc);
>>> + if (!mmc->supply.vmmc) {
>>> + ret = mmc_regulator_get_supply(mmc);
>>> + enable_vqmmc = true;
>>> + } else {
>>> + ret = 0;
>>> + }
>>> if (ret)
>>> return ret;
>>
>> Why not
>>
>> if (!mmc->supply.vmmc) {
>> ret = mmc_regulator_get_supply(mmc);
>> if (ret)
>> return ret;
>> enable_vqmmc = true;
>> }
>>
>
> looks neater. Will do.
>
>>> @@ -3736,7 +3742,10 @@ int sdhci_setup_host(struct sdhci_host *host)
>>> /* If vqmmc regulator and no 1.8V signalling, then there's no UHS */
>>> if (!IS_ERR(mmc->supply.vqmmc)) {
>>> - ret = regulator_enable(mmc->supply.vqmmc);
>>> + if (enable_vqmmc)
>>> + ret = regulator_enable(mmc->supply.vqmmc);
>>
>> Please introduce host->vqmmc_enabled = !ret;
>>
>
> Any reason to introduce vqmmc_enabled variable in sdhci_host structure ? We
> can get around with a local variable and using regulator_is_enabled API.
regulator_enable() uses reference counting, so we have to use
regulator_disable() exactly the same number of times that we use
regulator_enable().
>
>>> + else
>>> + ret = 0;
>>> if (!regulator_is_supported_voltage(mmc->supply.vqmmc, 1700000,
>>> 1950000))
>>> host->caps1 &= ~(SDHCI_SUPPORT_SDR104 |
>>> @@ -3984,7 +3993,7 @@ int sdhci_setup_host(struct sdhci_host *host)
>>> return 0;
>>> unreg:
>>> - if (!IS_ERR(mmc->supply.vqmmc))
>>> + if (!IS_ERR(mmc->supply.vqmmc) && enable_vqmmc)
>>
>> And just make this
>>
>> if (host->vqmmc_enabled)
>>
>>> regulator_disable(mmc->supply.vqmmc);
>>> undma:
>>> if (host->align_buffer)
>>> @@ -4002,7 +4011,8 @@ void sdhci_cleanup_host(struct sdhci_host *host)
>>> {
>>> struct mmc_host *mmc = host->mmc;
>>> - if (!IS_ERR(mmc->supply.vqmmc))
>>> + if (!IS_ERR(mmc->supply.vqmmc) &&
>>> + (regulator_is_enabled(mmc->supply.vqmmc) > 0))
>>
>> if (host->vqmmc_enabled)
>>
>>> regulator_disable(mmc->supply.vqmmc);
>>> if (host->align_buffer)
>>> @@ -4135,7 +4145,8 @@ void sdhci_remove_host(struct sdhci_host *host, int
>>> dead)
>>> tasklet_kill(&host->finish_tasklet);
>>> - if (!IS_ERR(mmc->supply.vqmmc))
>>> + if (!IS_ERR(mmc->supply.vqmmc) &&
>>> + (regulator_is_enabled(mmc->supply.vqmmc) > 0))
>>
>> if (host->vqmmc_enabled)
>>
>>> regulator_disable(mmc->supply.vqmmc);
>>> if (host->align_buffer)
>>>
>>
>> --
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>>
>
> Thanks,
> Vijay
>
