mmc: sdhci-of-at91: fix set_uhs_signaling rewriting of MC1R

[ Upstream commit 5987e6ded29d52e42fc7b06aa575c60a25eee38e ]

In set_uhs_signaling, the DDR bit is being set by fully writing the MC1R
register.
This can lead to accidental erase of certain bits in this register.
Avoid this by doing a read-modify-write operation.

Fixes: d0918764c1 ("mmc: sdhci-of-at91: fix MMC_DDR_52 timing selection")
Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
Tested-by: Karl Olsen <karl@micro-technic.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20220630090926.15061-1-eugen.hristev@microchip.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Eugen Hristev 2022-06-30 12:09:26 +03:00 committed by Greg Kroah-Hartman
parent 9d8b911fe3
commit b1b8034953

View File

@ -109,8 +109,13 @@ static void sdhci_at91_set_power(struct sdhci_host *host, unsigned char mode,
static void sdhci_at91_set_uhs_signaling(struct sdhci_host *host,
unsigned int timing)
{
if (timing == MMC_TIMING_MMC_DDR52)
sdhci_writeb(host, SDMMC_MC1R_DDR, SDMMC_MC1R);
u8 mc1r;
if (timing == MMC_TIMING_MMC_DDR52) {
mc1r = sdhci_readb(host, SDMMC_MC1R);
mc1r |= SDMMC_MC1R_DDR;
sdhci_writeb(host, mc1r, SDMMC_MC1R);
}
sdhci_set_uhs_signaling(host, timing);
}