Subject: [PATCH 20/23] mmc: sdhci-esdhc-imx: fix strobe DLL lock wrong clock issue

From: [email-masked] (Adrian Hunter)
Date: Tue, 10 May 2016 15:03:48 +0300

On 15/04/16 20:29, Dong Aisheng wrote:
> When enable DDR, the clock factor definition is changed.
> e.g. original 200Mhz will become 100Mhz one MIX_CTRL_DDREN bit is set
> So we need to update the clock setting then the strobe dll can lock
> the correct clock rate.
> 
> Additionally we also need disable the clock before locking strobe dll.
> 
> Signed-off-by: Dong Aisheng <[email-masked]>

Apart from redundant parentheses (refer below):

Acked-by: Adrian Hunter <[email-masked]>

> ---
>  drivers/mmc/host/sdhci-esdhc-imx.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
> index 07b1144..3ff213f 100644
> --- a/drivers/mmc/host/sdhci-esdhc-imx.c
> +++ b/drivers/mmc/host/sdhci-esdhc-imx.c
> @@ -852,6 +852,11 @@ static void esdhc_set_strobe_dll(struct sdhci_host *host)
>  	u32 v;
>  
>  	if (host->mmc->actual_clock > ESDHC_STROBE_DLL_CLK_FREQ) {
> +		/* disable clock before enabling strobe dll */
> +		writel(readl(host->ioaddr + ESDHC_VENDOR_SPEC) &
> +		       (~ESDHC_VENDOR_SPEC_FRC_SDCLK_ON),

Parentheses look redundant

> +		       host->ioaddr + ESDHC_VENDOR_SPEC);
> +
>  		/* force a reset on strobe dll */
>  		writel(ESDHC_STROBE_DLL_CTRL_RESET,
>  			host->ioaddr + ESDHC_STROBE_DLL_CTRL);
> @@ -913,6 +918,8 @@ static void esdhc_set_uhs_signaling(struct sdhci_host *host, unsigned timing)
>  		m |= ESDHC_MIX_CTRL_DDREN | ESDHC_MIX_CTRL_HS400_EN;
>  		writel(m, host->ioaddr + ESDHC_MIX_CTRL);
>  		imx_data->is_ddr = 1;
> +		/* update clock after enable DDR for strobe DLL lock */
> +		host->ops->set_clock(host, host->clock);
>  		esdhc_set_strobe_dll(host);
>  		break;
>  	}
>