[PATCH] mmc: sdhci: programmable clock calculation needs multiplier +1

[Sean Anderson]

On 4/12/24 15:26, curtis.machida at intel.com wrote:
> [You don't often get email from curtis.machida at intel.com. Learn why this is important at https://cas5-0-urlprotect.trendmicro.com:443/wis/clicktime/v1/query?url=https%3a%2f%2faka.ms%2fLearnAboutSenderIdentification&umid=4f25273f-b33b-4eb3-8643-c1f6eff8842b&auth=d807158c60b7d2502abde8a2fc01f40662980862-c95c2e418b830130ad99c91e42b2732e3f7e44ee ]
> 
> From: cmachida <curtis.machida at intel.com>
> 
> According to the SD Host Controller Simplified Specification v4.20,
> the multiplier value M is one more than the Clock Multiplier field.
> 
> Copied code from Linux project.  drivers/mmc/host/sdhci.c line 4405
> 
> Signed-off-by: cmachida <curtis.machida at intel.com>
> ---
> 
>  drivers/mmc/sdhci.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/mmc/sdhci.c b/drivers/mmc/sdhci.c
> index 0178ed8a11..a8476ec4e9 100644
> --- a/drivers/mmc/sdhci.c
> +++ b/drivers/mmc/sdhci.c
> @@ -929,6 +929,15 @@ int sdhci_setup_cfg(struct mmc_config *cfg, struct sdhci_host *host,
>                 debug("%s, caps_1: 0x%x\n", __func__, caps_1);
>                 host->clk_mul = (caps_1 & SDHCI_CLOCK_MUL_MASK) >>
>                                 SDHCI_CLOCK_MUL_SHIFT;
> +
> +               /*
> +                * In case the value in Clock Multiplier is 0, then programmable
> +                * clock mode is not supported, otherwise the actual clock
> +                * multiplier is one more than the value of Clock Multiplier
> +                * in the Capabilities Register.
> +                */
> +               if (host->clk_mul)
> +                       host->clk_mul += 1;
>         }
> 
>         if (host->max_clk == 0) {
> --
> 2.43.2
> 

Reviewed-by: Sean Anderson <sean.anderson at seco.com>