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 15:15:12 +0530 |
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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 ?
>> 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 >
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