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. -Tim -- 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
