[PATCH v1 04/11] spi: rockchip-sfc: sanity check minimum freq

[Kever Yang]

+ Jon Lin,

Hi Jon,

     Please help to review this patch.


Thanks,
- Kever
On 2022/2/22 09:31, Peter Geis wrote:
> The rockchip-sfc driver sanity checks the maximum frequency, but not the
> minimum frequency.
> This causes the probe to fail when a frequency isn't defined, such as
> with `sf probe 0`.
> Clamp the minimum frequency to the rockchip default clock rate.
>
> Signed-off-by: Peter Geis <pgwipeout at gmail.com>
> ---
>   drivers/spi/rockchip_sfc.c | 5 +++++
>   1 file changed, 5 insertions(+)
>
> diff --git a/drivers/spi/rockchip_sfc.c b/drivers/spi/rockchip_sfc.c
> index 851a6482985b..d0d2dc70a417 100644
> --- a/drivers/spi/rockchip_sfc.c
> +++ b/drivers/spi/rockchip_sfc.c
> @@ -164,6 +164,8 @@
>   /* DMA is only enabled for large data transmission */
>   #define SFC_DMA_TRANS_THRETHOLD		(0x40)
>   
> +#define SFC_MIN_SPEED		(24 * 1000 * 1000)
> +
>   /* Maximum clock values from datasheet suggest keeping clock value under
>    * 150MHz. No minimum or average value is suggested.
>    */
> @@ -596,6 +598,9 @@ static int rockchip_sfc_set_speed(struct udevice *bus, uint speed)
>   	if (speed > sfc->max_freq)
>   		speed = sfc->max_freq;
>   
> +	if (speed < SFC_MIN_SPEED)
> +		speed = SFC_MIN_SPEED;
> +
>   	if (speed == sfc->speed)
>   		return 0;
>