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

["Jaehoon Chung" <jh80.chung@samsung.com>]

> -----Original Message-----
> From: curtis.machida@intel.com <curtis.machida@intel.com>
> Sent: Saturday, April 13, 2024 4:27 AM
> To: u-boot@lists.denx.de; Peng Fan <peng.fan@nxp.com>; Jaehoon Chung <jh80.chung@samsung.com>
> Cc: cmachida <curtis.machida@intel.com>; Jonas Karlman <jonas@kwiboo.se>; Kever Yang <kever.yang@rock-
> chips.com>; Peter Geis <pgwipeout@gmail.com>; Sean Anderson <sean.anderson@seco.com>; Simon Glass
> <sjg@chromium.org>; Tom Rini <trini@konsulko.com>
> Subject: [PATCH] mmc: sdhci: programmable clock calculation needs multiplier +1
> 
> From: cmachida <curtis.machida@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@intel.com>

Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>

Best Regards,
Jaehoon Chung

> ---
> 
>  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