Stefan Agner 92748beac0 mmc: sdhci-esdhc-imx: allow 1.8V modes without 100/200MHz pinctrl states ... If pinctrl nodes for 100/200MHz are missing, the controller should not select any mode which need signal frequencies 100MHz or higher. To prevent such speed modes the driver currently uses the quirk flag SDHCI_QUIRK2_NO_1_8_V. This works nicely for SD cards since 1.8V signaling is required for all faster modes and slower modes use 3.3V signaling only. However, there are eMMC modes which use 1.8V signaling and run below 100MHz, e.g. DDR52 at 1.8V. With using SDHCI_QUIRK2_NO_1_8_V this mode is prevented. When using a fixed 1.8V regulator as vqmmc-supply the stack has no valid mode to use. In this tenuous situation the kernel continuously prints voltage switching errors: mmc1: Switching to 3.3V signalling voltage failed Avoid using SDHCI_QUIRK2_NO_1_8_V and prevent faster modes by altering the SDHCI capability register. With that the stack is able to select 1.8V modes even if no faster pinctrl states are available: # cat /sys/kernel/debug/mmc1/ios ... timing spec: 8 (mmc DDR52) signal voltage: 1 (1.80 V) ... Link: http://lkml.kernel.org/r/20180628081331.13051-1-stefan@agner.ch Signed-off-by: Stefan Agner <stefan@agner.ch> Fixes: ad93220de7 ("mmc: sdhci-esdhc-imx: change pinctrl state according to uhs mode") Cc: <stable@vger.kernel.org> # v4.13+ Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>		2018-07-09 11:17:47 +02:00
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core	mmc: core: cd_label must be last entry of mmc_gpio struct	2018-07-03 07:12:35 +02:00
host	mmc: sdhci-esdhc-imx: allow 1.8V modes without 100/200MHz pinctrl states	2018-07-09 11:17:47 +02:00
Kconfig	mmc: core: Remove option not to use blk-mq	2017-12-11 12:55:02 +01:00
Makefile	mmc: Kconfig: downgrade CONFIG_MMC_DEBUG for host drivers only	2017-08-30 14:01:34 +02:00