From 73e736f865780cf01652b863d2016dde480c0f6f Mon Sep 17 00:00:00 2001 From: Stefan Agner Date: Thu, 12 Jul 2018 10:07:24 +0200 Subject: [PATCH] mmc: sdhci-esdhc-imx: disable clocks before changing frequency In the uSDHC case (e.g. i.MX 6) clocks only get disabled if frequency is set to 0. However, it could be that the stack asks for a frequency change while clocks are on. In that case the function clears the divider registers (by clearing ESDHC_CLOCK_MASK) while the clock is enabled! This causes a short period of time where the clock is undivided (on a i.MX 6DL a clock of 196MHz has been measured). For older IP variants the driver disables clock by clearing some bits in ESDHC_SYSTEM_CONTROL. Make sure to disable card clock before changing frequency for uSDHC IP variants too. Signed-off-by: Stefan Agner Acked-by: Dong Aisheng Acked-by: Adrian Hunter Signed-off-by: Ulf Hansson --- drivers/mmc/host/sdhci-esdhc-imx.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c index dc55461ababa1..9e838409ce698 100644 --- a/drivers/mmc/host/sdhci-esdhc-imx.c +++ b/drivers/mmc/host/sdhci-esdhc-imx.c @@ -705,14 +705,14 @@ static inline void esdhc_pltfm_set_clock(struct sdhci_host *host, int div = 1; u32 temp, val; + if (esdhc_is_usdhc(imx_data)) { + val = readl(host->ioaddr + ESDHC_VENDOR_SPEC); + writel(val & ~ESDHC_VENDOR_SPEC_FRC_SDCLK_ON, + host->ioaddr + ESDHC_VENDOR_SPEC); + } + if (clock == 0) { host->mmc->actual_clock = 0; - - if (esdhc_is_usdhc(imx_data)) { - val = readl(host->ioaddr + ESDHC_VENDOR_SPEC); - writel(val & ~ESDHC_VENDOR_SPEC_FRC_SDCLK_ON, - host->ioaddr + ESDHC_VENDOR_SPEC); - } return; } -- 2.30.2