2012/11/20 Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>: > Hello, > > > On 11/20/2012 9:59 AM, Kevin Liu wrote: >> >> 2012/11/20 Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>: >> > Hello, >> > >> > >> > On 11/14/2012 8:11 AM, Kevin Liu wrote: >> >> >> >> > From: linux-mmc-owner@xxxxxxxxxxxxxxx >> >> > [mailto:linux-mmc-owner@xxxxxxxxxxxxxxx] On Behalf Of Chris Ball >> >> > Sent: Tuesday, November 13, 2012 10:14 PM >> >> > To: Marek Szyprowski >> >> > Cc: linux-kernel@xxxxxxxxxxxxxxx; linux-mmc@xxxxxxxxxxxxxxx; Kyungmin >> >> > Park; Mark Brown; Liam Girdwood; Philip Rakity >> >> > Subject: Re: [PATCH v2] mmc: sdhci: apply voltage range check only >> >> > for >> >> > non-fixed regulators >> >> > >> >> > Hi, >> >> > >> >> > On Tue, Nov 13 2012, Marek Szyprowski wrote: >> >> >>> On Tue, Nov 13 2012, Marek Szyprowski wrote: >> >> >>> > Fixed regulators cannot change their voltage, so disable all >> >> >>> > voltage >> >> >>> > range checking for them, otherwise the driver fails to operate >> >> >>> > with >> >> >>> > fixed regulators. Up to now it worked only by luck, because >> >> >>> > regulator_is_supported_voltage() function returned incorrect >> >> >>> > values. >> >> >>> > Commit "regulator: fix voltage check in >> >> >>> > regulator_is_supported_voltage()" >> >> >>> > fixed that function and now additional check is needed for fixed >> >> >>> > regulators. >> >> >>> > >> >> >>> > Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> >> >> >>> > --- >> >> >>> > drivers/mmc/host/sdhci.c | 2 +- >> >> >>> > 1 file changed, 1 insertion(+), 1 deletion(-) >> >> >>> > >> >> >>> > diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c >> >> >>> > index c7851c0..6f6534e 100644 >> >> >>> > --- a/drivers/mmc/host/sdhci.c >> >> >>> > +++ b/drivers/mmc/host/sdhci.c >> >> >>> > @@ -2923,7 +2923,7 @@ int sdhci_add_host(struct sdhci_host *host) >> >> >>> > regulator_enable(host->vmmc); >> >> >>> > >> >> >>> > #ifdef CONFIG_REGULATOR >> >> >>> > - if (host->vmmc) { >> >> >>> > + if (host->vmmc && regulator_count_voltages(host->vmmc) > 1) { >> >> >>> > ret = regulator_is_supported_voltage(host->vmmc, >> >> >>> > 3300000, >> >> >>> > 3300000); >> >> >>> > if ((ret <= 0) || (!(caps[0] & SDHCI_CAN_VDD_330))) >> >> >>> >> >> >>> Thanks for the longer explanation. I'm still missing something, >> >> >>> though; >> >> >>> what's wrong with running the check as it was with the new >> >> >>> regulator >> >> >>> code? >> >> >>> (I haven't tried it yet.) >> >> >>> >> >> >>> #ifdef CONFIG_REGULATOR >> >> >>> if (host->vmmc) { >> >> >>> ret = regulator_is_supported_voltage(host->vmmc, >> >> >>> 3300000, >> >> >>> 3300000); >> >> >>> if ((ret <= 0) || (!(caps[0] & >> >> >>> SDHCI_CAN_VDD_330))) >> >> >>> caps[0] &= ~SDHCI_CAN_VDD_330; >> >> >>> ret = regulator_is_supported_voltage(host->vmmc, >> >> >>> 3000000, >> >> >>> 3000000); >> >> >>> if ((ret <= 0) || (!(caps[0] & >> >> >>> SDHCI_CAN_VDD_300))) >> >> >>> caps[0] &= ~SDHCI_CAN_VDD_300; >> >> >>> ret = regulator_is_supported_voltage(host->vmmc, >> >> >>> 1800000, >> >> >>> 1800000); >> >> >>> if ((ret <= 0) || (!(caps[0] & >> >> >>> SDHCI_CAN_VDD_180))) >> >> >>> caps[0] &= ~SDHCI_CAN_VDD_180; >> >> >>> } >> >> >>> #endif /* CONFIG_REGULATOR */ >> >> >>> >> >> >>> The point is to remove unsupported voltages, so if someone sets up >> >> >>> a >> >> >>> fixed regulator at 3300000, all of the other caps are disabled. >> >> >>> Why >> >> >>> wouldn't that work without this change, and how are we supposed to >> >> >>> remove those caps on a fixed regulator after your patchset? >> >> >>> >> >> >>> Thanks, sorry if I'm missing something obvious, >> >> >> >> >> >> On our boards eMMC is connected to fixed 2.8V regulator, what >> >> >> results >> >> >> in >> >> >> clearing all available voltages and fail. The same situation is when >> >> >> one >> >> >> enable dummy regulator and try to use sdhci with it. My patch fixes >> >> >> this >> >> >> and restores sdhci to working state as it was before (before fixing >> >> >> regulator regulator_is_supported_voltage() function and earlier when >> >> >> MMC_BROKEN_VOLATGE capability was used). >> >> > >> >> > I see. Sounds like a separate bug -- Philip (or anyone else), any >> >> > idea how we should be treating eMMCs with a fixed voltage here? >> >> > >> >> >> >> I think we should check the voltage range rather than the voltage >> >> point accoring to the spec. >> >> Otherwise some valid voltage like 2.8v will be discarded by mistake. >> >> My below old patch aim to fix this issue. >> >> How do you think? >> >> >> >> -----Original Message----- >> >> From: Kevin Liu [mailto:keyuan.liu@xxxxxxxxx] >> >> Sent: Friday, September 28, 2012 3:56 PM >> >> To: linux-mmc@xxxxxxxxxxxxxxx; cjb@xxxxxxxxxx; pierre@xxxxxxxxx; >> >> ulf.hansson@xxxxxxxxxx; Zhangfei Gao >> >> Cc: Haojian Zhuang; Chao Xie; Philip Rakity; Kevin Liu; Jialing Fu >> >> Subject: [PATCH v5 03/13] mmc: sdhci: use regulator min/max voltage >> >> range according to spec >> >> >> >> From: Kevin Liu <kliu5@xxxxxxxxxxx> >> >> >> >> For regulator vmmc/vmmcq, use voltage range as below >> >> 3.3v/3.0v: (2.7v, 3.6v) >> >> 1.8v: (1.7v, 1.95v) >> >> Original code use the specific value which may fail in regulator >> >> driver if it does NOT support the specific voltage. >> >> >> >> Signed-off-by: Jialing Fu <jlfu@xxxxxxxxxxx> >> >> Signed-off-by: Kevin Liu <kliu5@xxxxxxxxxxx> >> > >> > >> > Tested-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> >> > >> > This patch restores sdhci devices to working state on Samsung boards >> > (tested on GONI and UniversalC210) after merging "regulator: fix voltage >> > check in regulator_is_supported_voltage()" patch to v3.7-rc6 (commit >> > f0f98b19e23d4426ca185e3d4ca80e6aff5ef51b). Would be great to have it >> > merged before the final v3.7 is out. >> > >> Marek, >> >> thanks a lot for the verification! >> And your patch "mmc: sdhci: apply voltage range check only for >> non-fixed regulators" (commit >> d5b5205f2d480a47863dda0772d2d9dc47c2b51b, which has been merged in >> mmc-next) can be reverted if this patch merged? > > > Yes, it can be replaced with it, although there is still an issue that need > to be resolved somehow. Right now SDHCI driver fails to initialize if > support > for dummy regulator is enabled. > Then I think the dummy issue can be resolved with your patch merged and if you can just update your patch from "regulator_count_voltages(host->vmmc) > 1" to "regulator_count_voltages(host->vmmc) > 0" to let fix regulator work. Thanks Kevin -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
