clk: renesas: rcar-gen3: Add documentation for SD clocks

Document the known use cases of the different clock settings. This is
useful as different SoC and ES versions use different settings to do
the same thing as there is more than one combination to achieve the
same SDn clock speed.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

diff --git a/drivers/clk/renesas/rcar-gen3-cpg.c b/drivers/clk/renesas/rcar-gen3-cpg.c
index 6033bacd25f6f7b9b5fa50ae63a6898da0d11a9b..7782ec198df28d0c6220fcdf594f165efe33b740 100644 (file)
--- a/drivers/clk/renesas/rcar-gen3-cpg.c
+++ b/drivers/clk/renesas/rcar-gen3-cpg.c
@@ -232,13 +232,13 @@ struct sd_clock {
  *                     sd_srcfc   sd_fc   div
  * stp_hck   stp_ck    (div)      (div)     = sd_srcfc x sd_fc
  *-------------------------------------------------------------------
- *  0         0         0 (1)      1 (4)      4
- *  0         0         1 (2)      1 (4)      8
- *  1         0         2 (4)      1 (4)     16
- *  1         0         3 (8)      1 (4)     32
+ *  0         0         0 (1)      1 (4)      4 : SDR104 / HS200 / HS400 (8 TAP)
+ *  0         0         1 (2)      1 (4)      8 : SDR50
+ *  1         0         2 (4)      1 (4)     16 : HS / SDR25
+ *  1         0         3 (8)      1 (4)     32 : NS / SDR12
  *  1         0         4 (16)     1 (4)     64
  *  0         0         0 (1)      0 (2)      2
- *  0         0         1 (2)      0 (2)      4
+ *  0         0         1 (2)      0 (2)      4 : SDR104 / HS200 / HS400 (4 TAP)
  *  1         0         2 (4)      0 (2)      8
  *  1         0         3 (8)      0 (2)     16
  *  1         0         4 (16)     0 (2)     32