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 15:52:00 +0530 |
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On 7/17/2018 3:24 PM, Adrian Hunter wrote: > On 17/07/18 12:45, Vijay Viswanath wrote: >> >> >> On 7/17/2018 2:12 PM, Adrian Hunter wrote: >>> On 17/07/18 11:40, Vijay Viswanath wrote: >>>> >>>> >>>> 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 ? >>> >>> Yes >>> >> >> Ok. >> Any particular reason why we are avoiding quirk and instead adding a new flag ? > > It moves more in the direction of letting drivers do what they want, rather > than trying to make making SDHCI do everything. >
ok will incorporate the changes in next version.
>> >>>> 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 >>>>>> >>>>> >>>> >>> >>> -- >>> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in >>> the body of a message to majordomo@vger.kernel.org >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>> >> >
Thanks, Vijay
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