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authorStefan Agner <stefan@agner.ch>2018-07-12 10:07:24 +0200
committerUlf Hansson <ulf.hansson@linaro.org>2018-07-16 11:41:05 +0200
commit73e736f865780cf01652b863d2016dde480c0f6f (patch)
tree84a70c6b29468974eb9a00e4107aacaf8d7c0a03 /drivers/mmc
parent726df1d5a62ec8241a2823f6b23728db61178eaa (diff)
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 <stefan@agner.ch> Acked-by: Dong Aisheng <aisheng.dong@nxp.com> Acked-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Diffstat (limited to 'drivers/mmc')
-rw-r--r--drivers/mmc/host/sdhci-esdhc-imx.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
index dc55461ababa..9e838409ce69 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;
}