On 24/08/16 13:03, Ritesh Harjani wrote:
> SDHC MSM controller need 2x clock for MCLK at GCC.
> Hence make required changes to have 2x clock for
> DDR timing modes.
>
> Signed-off-by: Ritesh Harjani <riteshh@xxxxxxxxxxxxxx>
> ---
> drivers/mmc/host/sdhci-msm.c | 22 ++++++++++++++++++----
> 1 file changed, 18 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
> index 853639b..538594c 100644
> --- a/drivers/mmc/host/sdhci-msm.c
> +++ b/drivers/mmc/host/sdhci-msm.c
> @@ -667,21 +667,35 @@ static void sdhci_msm_set_clock(struct sdhci_host *host, unsigned int clock)
> {
> struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);
> - u32 msm_clock = 0;
> + struct mmc_ios curr_ios = host->mmc->ios;
> + u32 msm_clock, ddr_clock;
> int rc = 0;
>
> if (!clock)
> goto out;
>
> - if (clock != msm_host->clk_rate) {
> - msm_clock = sdhci_msm_get_msm_clk_rate(host, clock);
> + msm_clock = sdhci_msm_get_msm_clk_rate(host, clock);
> + if ((curr_ios.timing == MMC_TIMING_UHS_DDR50) ||
> + (curr_ios.timing == MMC_TIMING_MMC_DDR52) ||
> + (curr_ios.timing == MMC_TIMING_MMC_HS400)) {
> + /*
> + * The SDHC requires internal clock frequency to be double the
> + * actual clock that will be set for DDR mode. The controller
> + * uses the faster clock(100/400MHz) for some of its parts and
> + * send the actual required clock (50/200MHz) to the card.
> + */
> + ddr_clock = clock * 2;
> + msm_clock = sdhci_msm_get_msm_clk_rate(host, ddr_clock);
> + }
> +
Could be slightly simpler e.g.
if ((curr_ios.timing == MMC_TIMING_UHS_DDR50) ||
(curr_ios.timing == MMC_TIMING_MMC_DDR52) ||
(curr_ios.timing == MMC_TIMING_MMC_HS400)) {
/*
* The SDHC requires internal clock frequency to be double the
* actual clock that will be set for DDR mode. The controller
* uses the faster clock(100/400MHz) for some of its parts and
* send the actual required clock (50/200MHz) to the card.
*/
clock *= 2;
}
msm_clock = sdhci_msm_get_msm_clk_rate(host, clock);
> + if (msm_clock != msm_host->clk_rate) {
> rc = clk_set_rate(msm_host->clk, msm_clock);
> if (rc) {
> pr_err("%s: failed to set clock at rate %u, requested clock rate %u\n",
> mmc_hostname(host->mmc), msm_clock, clock);
> goto out;
> }
> - msm_host->clk_rate = clock;
> + msm_host->clk_rate = msm_clock;
> pr_debug("%s: setting clock at rate %lu\n",
> mmc_hostname(host->mmc), clk_get_rate(msm_host->clk));
> }
>
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