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[1/3] clk: renesas: rcar-gen3-cpg: document SD divider usage

Message ID 20170801104603.10459-2-wsa+renesas@sang-engineering.com (mailing list archive)
State Rejected
Delegated to: Stephen Boyd
Headers show

Commit Message

Wolfram Sang Aug. 1, 2017, 10:46 a.m. UTC 
Document the intended use case for the SD dividers.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 drivers/clk/renesas/rcar-gen3-cpg.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)
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Patch

diff --git a/drivers/clk/renesas/rcar-gen3-cpg.c b/drivers/clk/renesas/rcar-gen3-cpg.c
index 3dee900522b703..81b7713afd694c 100644
--- a/drivers/clk/renesas/rcar-gen3-cpg.c
+++ b/drivers/clk/renesas/rcar-gen3-cpg.c
@@ -62,14 +62,16 @@  struct sd_clock {
 	unsigned int div_max;
 };
 
-/* SDn divider
+/*
+ * SDn dividers - recommended settings from HW engineers
+ *
  *                     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
+ *  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