Messages in this thread | | | Subject | Re: [PATCH RFC 1/2] mmc: sdhci: Allow platform controlled voltage switching | From | Vijay Viswanath <> | Date | Tue, 17 Jul 2018 14:10:21 +0530 |
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On 7/17/2018 1:00 PM, Adrian Hunter wrote: > On 17/07/18 08:14, Vijay Viswanath wrote: >> >> >> On 7/10/2018 4:37 PM, Adrian Hunter wrote: >>> On 21/06/18 15:23, 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. >>>> >>>> Add a quirk, which can be used by drivers of such controllers. >>>> >>>> Signed-off-by: Vijay Viswanath <vviswana@codeaurora.org> >>>> --- >>>> drivers/mmc/host/sdhci.c | 20 +++++++++++++++----- >>>> drivers/mmc/host/sdhci.h | 2 ++ >>>> 2 files changed, 17 insertions(+), 5 deletions(-) >>>> >>>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c >>>> index 1c828e0..f0346d4 100644 >>>> --- a/drivers/mmc/host/sdhci.c >>>> +++ b/drivers/mmc/host/sdhci.c >>>> @@ -1615,7 +1615,8 @@ void sdhci_set_power_noreg(struct sdhci_host *host, >>>> unsigned char mode, >>>> void sdhci_set_power(struct sdhci_host *host, unsigned char mode, >>>> unsigned short vdd) >>>> { >>>> - if (IS_ERR(host->mmc->supply.vmmc)) >>>> + if (IS_ERR(host->mmc->supply.vmmc) || >>>> + (host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL)) >>> >>> I think you should provide your own ->set_power() instead of this >>> >> >> will do >> >>>> sdhci_set_power_noreg(host, mode, vdd); >>>> else >>>> sdhci_set_power_reg(host, mode, vdd); >>>> @@ -2009,7 +2010,9 @@ int sdhci_start_signal_voltage_switch(struct >>>> mmc_host *mmc, >>>> ctrl &= ~SDHCI_CTRL_VDD_180; >>>> sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2); >>>> - if (!IS_ERR(mmc->supply.vqmmc)) { >>>> + if (!IS_ERR(mmc->supply.vqmmc) && >>>> + !(host->quirks2 & >>>> + SDHCI_QUIRK2_INTERNAL_PWR_CTL)) { >>> >>> And your own ->start_signal_voltage_switch() >>> >> >> sdhci_msm_start_signal_voltage_switch() would be an exact copy of >> sdhci_start_signal_voltage_switch()..... will incorporate this if not using >> quirk. >> >>>> ret = mmc_regulator_set_vqmmc(mmc, ios); >>>> if (ret) { >>>> pr_warn("%s: Switching to 3.3V signalling voltage >>>> failed\n", >>>> @@ -2032,7 +2035,8 @@ int sdhci_start_signal_voltage_switch(struct >>>> mmc_host *mmc, >>>> case MMC_SIGNAL_VOLTAGE_180: >>>> if (!(host->flags & SDHCI_SIGNALING_180)) >>>> return -EINVAL; >>>> - if (!IS_ERR(mmc->supply.vqmmc)) { >>>> + if (!IS_ERR(mmc->supply.vqmmc) && >>>> + !(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL)) { >>>> ret = mmc_regulator_set_vqmmc(mmc, ios); >>>> if (ret) { >>>> pr_warn("%s: Switching to 1.8V signalling voltage >>>> failed\n", >>>> @@ -3485,7 +3489,10 @@ 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 (!(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL)) >>> >>> Since we expect mmc_regulator_get_supply() to have been called, this could >>> be: >>> >>> if (!mmc->supply.vmmc) { >>> ret = mmc_regulator_get_supply(mmc); >>> enable_vqmmc = true; >>> } else { >>> ret = 0; >>> } >>>>> + ret = mmc_regulator_get_supply(mmc); >>>> + else >>>> + ret = 0; >>>> if (ret) >>>> return ret; >>>> @@ -3736,7 +3743,10 @@ 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 (!(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL)) >>> >>> And this could be: >>> >>> if (enable_vqmmc) >>> ret = regulator_enable(mmc->supply.vqmmc); >>> else >>> ret = 0; >>> > However, you still need to ensure regulator_disable(mmc->supply.vqmmc) is >>> only called if regulator_enable() was called. >> I missed this. Will cover it. >> >> Also I missed one more place where we are doing regulator_disable. During >> sdhci-msm unbinding, we would end up doing an extra regulator disable >> (thanks Evan for pointing it out) in sdhci_remove_host. >> >> To avoid the quirk( or having any flag), it would require copying the code >> of sdhci_start_signal_voltage_switch() and sdhci_remove_host() and creating > > You do not need to duplicate sdhci_remove_host(), just change it so that it > only disables what was enabled i.e. > > if (host->vqmmc_enabled) > regulator_disable(mmc->supply.vqmmc); >
Ok, so we will be adding a new flag "vqmmc_enabled" in sdhci_host, ryt ? Just wanted to clarify
>> 2 new functions in sdhci_msm layer which would do the exact same as above, >> with just the regulator parts removed. >> >> This looks messy (considering any future changes to the 2 sdhci API will >> need to be copied to their duplicate sdhci_msm API) and a bit overkill to >> avoid quirk. At the same time, I don't know how useful such a quirk would be >> to other platform drivers. >> >> Please let me know your view/suggestions. > > Let's try without the quirk. > >>> >>>> + ret = regulator_enable(mmc->supply.vqmmc); >>>> + else >>>> + ret = 0; >>>> if (!regulator_is_supported_voltage(mmc->supply.vqmmc, 1700000, >>>> 1950000)) >>>> host->caps1 &= ~(SDHCI_SUPPORT_SDR104 | >>>> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h >>>> index 23966f8..3b0c97a 100644 >>>> --- a/drivers/mmc/host/sdhci.h >>>> +++ b/drivers/mmc/host/sdhci.h >>>> @@ -450,6 +450,8 @@ struct sdhci_host { >>>> * obtainable timeout. >>>> */ >>>> #define SDHCI_QUIRK2_DISABLE_HW_TIMEOUT (1<<17) >>>> +/* Regulator voltage changes are being done from platform layer */ >>>> +#define SDHCI_QUIRK2_INTERNAL_PWR_CTL (1<<18) >>> >>> So maybe the quirk is not needed. >>> >>>> int irq; /* Device IRQ */ >>>> void __iomem *ioaddr; /* Mapped address */ >>>> >>> >> >> Thanks for the review & suggestions! >> Vijay >> >
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