[U-Boot] [PATCH 7/7] clk: stm32mp1: correctly handle Clock Spreading Generator

[Patrick Delaunay]

To activate the csg option, the driver need to set the bit2
of PLLNCR register = SSCG_CTRL: Spread Spectrum Clock Generator
of PLLn enable.

Signed-off-by: Patrick Delaunay <patrick.delaunay at st.com>
---

 doc/device-tree-bindings/clock/st,stm32mp1.txt | 10 +++++-----
 drivers/clk/clk_stm32mp1.c                     |  8 +++++++-
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/doc/device-tree-bindings/clock/st,stm32mp1.txt b/doc/device-tree-bindings/clock/st,stm32mp1.txt
index 6a9397e..ffcf8cd 100644
--- a/doc/device-tree-bindings/clock/st,stm32mp1.txt
+++ b/doc/device-tree-bindings/clock/st,stm32mp1.txt
@@ -132,15 +132,15 @@ Optional Properties:
 				frac = < 0x810 >;
 			};
 			st,pll at 1 {
-				cfg = < 1 43 1 0 0 PQR(0,1,1)>;
-				csg = <10 20 1>;
+				cfg = < 1 43 1 0 0 PQR(0,1,1) >;
+				csg = < 10 20 1 >;
 			};
 			st,pll at 2 {
-				cfg = < 2 85 3 13 3 0>;
-				csg = <10 20 SSCG_MODE_CENTER_SPREAD>;
+				cfg = < 2 85 3 13 3 0 >;
+				csg = < 10 20 SSCG_MODE_CENTER_SPREAD >;
 			};
 			st,pll at 3 {
-				cfg = < 2 78 4 7 9 3>;
+				cfg = < 2 78 4 7 9 3 >;
 			};
 			st,pkcs = <
 					CLK_STGEN_HSE
diff --git a/drivers/clk/clk_stm32mp1.c b/drivers/clk/clk_stm32mp1.c
index 76b7b5a..24859fd 100644
--- a/drivers/clk/clk_stm32mp1.c
+++ b/drivers/clk/clk_stm32mp1.c
@@ -167,6 +167,7 @@
 /* used for ALL PLLNCR registers */
 #define RCC_PLLNCR_PLLON	BIT(0)
 #define RCC_PLLNCR_PLLRDY	BIT(1)
+#define RCC_PLLNCR_SSCG_CTRL	BIT(2)
 #define RCC_PLLNCR_DIVPEN	BIT(4)
 #define RCC_PLLNCR_DIVQEN	BIT(5)
 #define RCC_PLLNCR_DIVREN	BIT(6)
@@ -1321,7 +1322,10 @@ static void pll_start(struct stm32mp1_clk_priv *priv, int pll_id)
 {
 	const struct stm32mp1_clk_pll *pll = priv->data->pll;
 
-	writel(RCC_PLLNCR_PLLON, priv->base + pll[pll_id].pllxcr);
+	clrsetbits_le32(priv->base + pll[pll_id].pllxcr,
+			RCC_PLLNCR_DIVPEN | RCC_PLLNCR_DIVQEN |
+			RCC_PLLNCR_DIVREN,
+			RCC_PLLNCR_PLLON);
 }
 
 static int pll_output(struct stm32mp1_clk_priv *priv, int pll_id, int output)
@@ -1440,6 +1444,8 @@ static void pll_csg(struct stm32mp1_clk_priv *priv, int pll_id, u32 *csg)
 		    RCC_PLLNCSGR_SSCG_MODE_MASK);
 
 	writel(pllxcsg, priv->base + pll[pll_id].pllxcsgr);
+
+	setbits_le32(priv->base + pll[pll_id].pllxcr, RCC_PLLNCR_SSCG_CTRL);
 }
 
 static int set_clksrc(struct stm32mp1_clk_priv *priv, unsigned int clksrc)
-- 
2.7.4