On Thu, Jun 19, 2014 at 2:40 PM, Tim Kryger <tim.kryger@xxxxxxxxx> wrote: > On Thu, Jun 19, 2014 at 1:49 AM, Sachin Kamat <spk.linux@xxxxxxxxx> wrote: >> +cc Some relevant guys from Samsung >> >> On Thu, Jun 19, 2014 at 2:12 PM, Tim Kryger <tim.kryger@xxxxxxxxx> wrote: >>> On Wed, Jun 18, 2014 at 8:54 PM, Sachin Kamat <spk.linux@xxxxxxxxx> wrote: >>> >>>>> On Wed, Jun 18, 2014 at 4:33 AM, Sachin Kamat <spk.linux@xxxxxxxxx> wrote: >>> >>>>>> I see the below error on Exynos4210 based Origen board with linux-next >>>>>> (20140618). >>>>>> Reverting the below commit works fine. >>>>>> >>>>>> Commit: 8d02e775a6 "mmc: sdhci: Use mmc core regulator infrastucture" >>> >>>>>> >>>>>> -- [ 2.068992] sdhci: Secure Digital Host Controller Interface driver >>>>>> [ 2.075059] sdhci: Copyright(c) Pierre Ossman >>>>>> [ 2.079762] of_get_named_gpiod_flags: can't parse gpios property of >>>>>> node '/sdhci@12510000[0]' >>>>>> [ 2.088021] s3c-sdhci 12510000.sdhci: clock source 2: mmc_busclk.2 >>>>>> (50000000 Hz) >>>>>> [ 2.095322] of_get_named_gpiod_flags: can't parse gpios property of >>>>>> node '/sdhci@12510000[0]' >>>>>> [ 2.103794] of_get_named_gpiod_flags: can't parse gpios property of >>>>>> node '/sdhci@12510000[0]' >>>>>> [ 2.112478] s3c-sdhci 12510000.sdhci: No vqmmc regulator found >>>>>> [ 2.118117] mmc0: Hardware doesn't report any support voltages. >>>>>> [ 2.124004] s3c-sdhci 12510000.sdhci: sdhci_add_host() failed >>>>>> [ 2.130080] of_get_named_gpiod_flags: can't parse gpios property of >>>>>> node '/sdhci@12530000[0]' >>>>>> [ 2.138352] s3c-sdhci 12530000.sdhci: clock source 2: mmc_busclk.2 >>>>>> (16666667 Hz) >>>>>> [ 2.145661] of_get_named_gpiod_flags: can't parse gpios property of >>>>>> node '/sdhci@12530000[0]' >>>>>> [ 2.154139] of_get_named_gpiod_flags: can't parse gpios property of >>>>>> node '/sdhci@12530000[0]' >>>>>> [ 2.162834] s3c-sdhci 12530000.sdhci: No vqmmc regulator found >>>>>> [ 2.168464] mmc0: Hardware doesn't report any support voltages. >>>>>> [ 2.174349] s3c-sdhci 12530000.sdhci: sdhci_add_host() failed >>> >>>>>> [ 2.336148] Waiting for root device /dev/mmcblk0p1... >>> >>>> FYI, the board has a 2.8V fixed regulator supply connected to the MMC. >>>> You may refer to arch/arm/boot/dts/exynos4210-origen.dts for more details. >>> >>> A 2.8v regulator results in mmc->ocr_avail being set to MMC_VDD_27_28 >>> | MMC_VDD_28_29. >>> >>> The SDHCI capabilities register only indicates support of three voltage levels >>> - 1.8v: SDHCI_CAN_VDD_180 => MMC_VDD_165_195 >>> - 3.0v: SDHCI_CAN_VDD_300 => MMC_VDD_29_30 | MMC_VDD_30_31 >>> - 3.3v: SDHCI_CAN_VDD_330 => MMC_VDD_32_33 | MMC_VDD_33_34 >>> >>> Even if all capability bits of the host controller were set, there >>> still wouldn't be any overlap. Thus you see a "Hardware doesn't >>> report any support voltages" message. >>> >>> Previously, this issue was being swept under the rug by cec2e21 mmc: >>> sdhci: Use regulator min/max voltage range according to spec. That >>> change hacked up the voltage range checks such that with your 2.8v >>> fixed regulator, the driver would believe the host could support >>> MMC_VDD_29_30 | MMC_VDD_30_31 | MMC_VDD_32_33 | MMC_VDD_33_34. The >>> driver would start down the path of commanding 3.3v-3.4v (the highest >>> voltage range believed to be supported). At the last second, the >>> driver would see the regulator was fixed and blindly skip over the set >>> voltage operation, saving it from failure. >>> >>> Since my patch eliminates the bogus voltage range checks, your board >>> is now getting caught playing too loose with the SDHCI regulator >>> voltages. >>> >>> Furthermore, the fixed regulator special-case logic that helped hide >>> your issue should also be considered for removal given that fixed >>> regulators now behave properly thanks to c00dc35 regulator: core: >>> Allow regulator_set_voltage for fixed regulators. >> >> Thanks for the detailed explanation. What do you propose to get this fixed? > > I'm not really sure of the best path forward. I suppose you could > modify your device tree to lie about the voltage of the fixed > regulator. Changing it to 3.0v should allow it to boot up but that is > definitely a hack. Or I could simply remove the vmmc-supply property altogether (as it is optional) and get the board to work. > It would be nice if the driver could be extended > to handle the peculiarities of your board in a deliberate manner but > limiting the common sdhci driver to supporting only the three voltages > from the spec also seems sensible. Until such time that the driver gets fixed to handle 2.8V fixed supply your current patch leaves several of Exynos boards broken for now. -- Regards, Sachin. -- 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
