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 6033bac..7782ec1 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