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SubjectRe: [PATCH] mmc: sdhci-esdhc-imx: disable clocks before changing frequency
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On 05/07/18 14:39, Stefan Agner wrote:
> 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 chainging frequency for uSDHC

chainging -> changing

> IP variants too. Also fix indent to make disable/enable clock look
> alike.
>
> Signed-off-by: Stefan Agner <stefan@agner.ch>
> ---
> drivers/mmc/host/sdhci-esdhc-imx.c | 14 +++++++-------
> 1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
> index 85fd5a8b0b6d..aa48f4b2541a 100644
> --- a/drivers/mmc/host/sdhci-esdhc-imx.c
> +++ b/drivers/mmc/host/sdhci-esdhc-imx.c
> @@ -708,14 +708,14 @@ 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;
> }
>
> @@ -761,7 +761,7 @@ static inline void esdhc_pltfm_set_clock(struct sdhci_host *host,
> 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);
> + host->ioaddr + ESDHC_VENDOR_SPEC);

Ideally each patch does only 1 thing. Please make white-space fix-up a
separate patch.

> }
>
> mdelay(1);
>

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