diff mbox series

clk: renesas: r8a779h0: Drop CLK_PLL2_DIV2 to clarify ZCn clocks

Message ID 0d2789cac2bf306145fe0bbf269c2da5942bb68f.1728377724.git.geert+renesas@glider.be (mailing list archive)
State Accepted
Delegated to: Geert Uytterhoeven
Headers show
Series clk: renesas: r8a779h0: Drop CLK_PLL2_DIV2 to clarify ZCn clocks | expand

Commit Message

Geert Uytterhoeven Oct. 8, 2024, 8:59 a.m. UTC 
Early revisions of the R-Car V4M Series Hardware User’s Manual
contained an incorrect formula for the CPU core clocks:

    ZCnφ = (PLL2VCO x 1/2) x mult/32

Dang-san fixed this by using CLK_PLL2_DIV2 instead of CLK_PLL2 as the
parent clock.

In Rev.0.70 of the documentation, the formula was corrected to:

    ZCnφ = (PLL2VCO x 1/4) x mult/32

As the CPG Block Diagram now shows a separate 1/4 post-divider for PLL2,
the use of CLK_PLL2_DIV2 is a recurring source of confusion.  Hence get
rid of CLK_PLL2_DIV2, and include the proper 1/4 post-divider in the
invocation of the DEF_GEN4_Z() macro, like is done on other R-Car Gen4
(and Gen3) SoCs.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
To be queued in renesas-clk for v6.13.
---
 drivers/clk/renesas/r8a779h0-cpg-mssr.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

Comments

Kuninori Morimoto Oct. 8, 2024, 11:48 p.m. UTC | #1 
Hi Geert

> Early revisions of the R-Car V4M Series Hardware User’s Manual
> contained an incorrect formula for the CPU core clocks:
> 
>     ZCnφ = (PLL2VCO x 1/2) x mult/32
> 
> Dang-san fixed this by using CLK_PLL2_DIV2 instead of CLK_PLL2 as the
> parent clock.
> 
> In Rev.0.70 of the documentation, the formula was corrected to:
> 
>     ZCnφ = (PLL2VCO x 1/4) x mult/32
> 
> As the CPG Block Diagram now shows a separate 1/4 post-divider for PLL2,
> the use of CLK_PLL2_DIV2 is a recurring source of confusion.  Hence get
> rid of CLK_PLL2_DIV2, and include the proper 1/4 post-divider in the
> invocation of the DEF_GEN4_Z() macro, like is done on other R-Car Gen4
> (and Gen3) SoCs.
> 
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> ---

Please add

Reported-by: Vinh Nguyen <vinh.nguyen.xz@renesas.com>

Thank you for your help !!

Best regards
---
Kuninori Morimoto
diff mbox series

Patch

diff --git a/drivers/clk/renesas/r8a779h0-cpg-mssr.c b/drivers/clk/renesas/r8a779h0-cpg-mssr.c
index e20c048bfa9be142..9067e407cbc69f00 100644
--- a/drivers/clk/renesas/r8a779h0-cpg-mssr.c
+++ b/drivers/clk/renesas/r8a779h0-cpg-mssr.c
@@ -37,7 +37,6 @@  enum clk_ids {
 	CLK_PLL5,
 	CLK_PLL6,
 	CLK_PLL1_DIV2,
-	CLK_PLL2_DIV2,
 	CLK_PLL3_DIV2,
 	CLK_PLL4_DIV2,
 	CLK_PLL4_DIV5,
@@ -78,7 +77,6 @@  static const struct cpg_core_clk r8a779h0_core_clks[] __initconst = {
 	DEF_GEN4_PLL_V8_25(".pll6", 6,	CLK_PLL6,		CLK_MAIN),
 
 	DEF_FIXED(".pll1_div2",	CLK_PLL1_DIV2,	CLK_PLL1,	2, 1),
-	DEF_FIXED(".pll2_div2",	CLK_PLL2_DIV2,	CLK_PLL2,	2, 1),
 	DEF_FIXED(".pll3_div2",	CLK_PLL3_DIV2,	CLK_PLL3,	2, 1),
 	DEF_FIXED(".pll4_div2",	CLK_PLL4_DIV2,	CLK_PLL4,	2, 1),
 	DEF_FIXED(".pll4_div5",	CLK_PLL4_DIV5,	CLK_PLL4,	5, 1),
@@ -101,10 +99,10 @@  static const struct cpg_core_clk r8a779h0_core_clks[] __initconst = {
 	DEF_RATE(".oco",	CLK_OCO,	32768),
 
 	/* Core Clock Outputs */
-	DEF_GEN4_Z("zc0",	R8A779H0_CLK_ZC0,	CLK_TYPE_GEN4_Z,	CLK_PLL2_DIV2,	2, 0),
-	DEF_GEN4_Z("zc1",	R8A779H0_CLK_ZC1,	CLK_TYPE_GEN4_Z,	CLK_PLL2_DIV2,	2, 8),
-	DEF_GEN4_Z("zc2",	R8A779H0_CLK_ZC2,	CLK_TYPE_GEN4_Z,	CLK_PLL2_DIV2,	2, 32),
-	DEF_GEN4_Z("zc3",	R8A779H0_CLK_ZC3,	CLK_TYPE_GEN4_Z,	CLK_PLL2_DIV2,	2, 40),
+	DEF_GEN4_Z("zc0",	R8A779H0_CLK_ZC0,	CLK_TYPE_GEN4_Z,	CLK_PLL2,	4, 0),
+	DEF_GEN4_Z("zc1",	R8A779H0_CLK_ZC1,	CLK_TYPE_GEN4_Z,	CLK_PLL2,	4, 8),
+	DEF_GEN4_Z("zc2",	R8A779H0_CLK_ZC2,	CLK_TYPE_GEN4_Z,	CLK_PLL2,	4, 32),
+	DEF_GEN4_Z("zc3",	R8A779H0_CLK_ZC3,	CLK_TYPE_GEN4_Z,	CLK_PLL2,	4, 40),
 	DEF_FIXED("s0d2",	R8A779H0_CLK_S0D2,	CLK_S0,		2, 1),
 	DEF_FIXED("s0d3",	R8A779H0_CLK_S0D3,	CLK_S0,		3, 1),
 	DEF_FIXED("s0d4",	R8A779H0_CLK_S0D4,	CLK_S0,		4, 1),