Re: [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 <pgwipe...@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;