[PATCH 1/3] mmc: stm32_sdmmc2: add dual data rate support

[Jaehoon Chung]

On 9/13/22 20:23, Yann Gautier wrote:
> To support dual data rate with STM32 sdmmc2 driver, the dedicated bit
> (DDR - BIT(18)) needs to be set in the CLKRC register. Clock bypass
> (no divider) is not allowed in this case. This is required for the
> eMMC DDR modes.
> 
> Signed-off-by: Yann Gautier <yann.gautier at foss.st.com>

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

Best Regards,
Jaehoon Chung

> ---
> 
>  drivers/mmc/stm32_sdmmc2.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mmc/stm32_sdmmc2.c b/drivers/mmc/stm32_sdmmc2.c
> index bfce8a2e4a..3cfa5a66f1 100644
> --- a/drivers/mmc/stm32_sdmmc2.c
> +++ b/drivers/mmc/stm32_sdmmc2.c
> @@ -598,13 +598,16 @@ static int stm32_sdmmc2_set_ios(struct udevice *dev)
>  	 * clk_div > 0 and NEGEDGE = 1 => command and data generated on
>  	 * SDMMCCLK falling edge
>  	 */
> -	if (desired && ((sys_clock > desired) ||
> +	if (desired && (sys_clock > desired || mmc->ddr_mode ||
>  			IS_RISING_EDGE(plat->clk_reg_msk))) {
>  		clk = DIV_ROUND_UP(sys_clock, 2 * desired);
>  		if (clk > SDMMC_CLKCR_CLKDIV_MAX)
>  			clk = SDMMC_CLKCR_CLKDIV_MAX;
>  	}
>  
> +	if (mmc->ddr_mode)
> +		clk |= SDMMC_CLKCR_DDR;
> +
>  	if (mmc->bus_width == 4)
>  		clk |= SDMMC_CLKCR_WIDBUS_4;
>  	if (mmc->bus_width == 8)