clk: clk_stm32f: Configure SAI PLL to generate LTDC pixel clock

Configure SAI PLL configuration to generate LTDC pixel clock on
the PLLSAIR output.

PLLSAI is enabled only if CONFIG_VIDEO_STM32 flag is set.

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>

diff --git a/drivers/clk/clk_stm32f.c b/drivers/clk/clk_stm32f.c
index a687e2a..a11d6dc 100644 (file)
--- a/drivers/clk/clk_stm32f.c
+++ b/drivers/clk/clk_stm32f.c
@@ -65,13 +65,17 @@
 #define RCC_PLLSAICFGR_PLLSAIR_SHIFT   28
 #define RCC_PLLSAICFGR_PLLSAIP_4       BIT(16)
 #define RCC_PLLSAICFGR_PLLSAIQ_4       BIT(26)
-#define RCC_PLLSAICFGR_PLLSAIR_2       BIT(29)
+#define RCC_PLLSAICFGR_PLLSAIR_3       BIT(29) | BIT(28)
 
 #define RCC_DCKCFGRX_TIMPRE            BIT(24)
 #define RCC_DCKCFGRX_CK48MSEL          BIT(27)
 #define RCC_DCKCFGRX_SDMMC1SEL         BIT(28)
 #define RCC_DCKCFGR2_SDMMC2SEL         BIT(29)
 
+#define RCC_DCKCFGR_PLLSAIDIVR_SHIFT    16
+#define RCC_DCKCFGR_PLLSAIDIVR_MASK    GENMASK(17, 16)
+#define RCC_DCKCFGR_PLLSAIDIVR_2       0
+
 /*
  * RCC AHB1ENR specific definitions
  */
@@ -132,6 +136,8 @@ struct stm32_clk {
        unsigned long hse_rate;
 };
 
+static const u8 pllsaidivr_table[] = { 2, 4, 8, 16 };
+
 static int configure_clocks(struct udevice *dev)
 {
        struct stm32_clk *priv = dev_get_priv(dev);
@@ -187,11 +193,29 @@ static int configure_clocks(struct udevice *dev)
                clrbits_le32(&regs->dckcfgr, RCC_DCKCFGRX_SDMMC1SEL);
        }
 
+#ifdef CONFIG_VIDEO_STM32
+       /*
+        * Configure the SAI PLL to generate LTDC pixel clock
+        */
+       clrsetbits_le32(&regs->pllsaicfgr, RCC_PLLSAICFGR_PLLSAIR_MASK,
+                       RCC_PLLSAICFGR_PLLSAIR_3);
+       clrsetbits_le32(&regs->pllsaicfgr, RCC_PLLSAICFGR_PLLSAIN_MASK,
+                       195 << RCC_PLLSAICFGR_PLLSAIN_SHIFT);
+
+       clrsetbits_le32(&regs->dckcfgr, RCC_DCKCFGR_PLLSAIDIVR_MASK,
+                       RCC_DCKCFGR_PLLSAIDIVR_2 << RCC_DCKCFGR_PLLSAIDIVR_SHIFT);
+#endif
        /* Enable the main PLL */
        setbits_le32(&regs->cr, RCC_CR_PLLON);
        while (!(readl(&regs->cr) & RCC_CR_PLLRDY))
                ;
 
+#ifdef CONFIG_VIDEO_STM32
+/* Enable the SAI PLL */
+       setbits_le32(&regs->cr, RCC_CR_PLLSAION);
+       while (!(readl(&regs->cr) & RCC_CR_PLLSAIRDY))
+               ;
+#endif
        setbits_le32(&regs->apb1enr, RCC_APB1ENR_PWREN);
 
        if (priv->info.has_overdrive) {
@@ -361,6 +385,8 @@ static ulong stm32_clk_get_rate(struct clk *clk)
        u32 sysclk = 0;
        u32 vco;
        u32 sdmmcxsel_bit;
+       u32 saidivr;
+       u32 pllsai_rate;
        u16 pllm, plln, pllp, pllq;
 
        if ((readl(&regs->cfgr) & RCC_CFGR_SWS_MASK) ==
@@ -438,6 +464,15 @@ static ulong stm32_clk_get_rate(struct clk *clk)
                case STM32F7_APB2_CLOCK(TIM11):
                        return stm32_get_timer_rate(priv, sysclk, APB2);
                break;
+
+               /* particular case for LTDC clock */
+               case STM32F7_APB2_CLOCK(LTDC):
+                       saidivr = readl(&regs->dckcfgr);
+                       saidivr = (saidivr & RCC_DCKCFGR_PLLSAIDIVR_MASK)
+                                 >> RCC_DCKCFGR_PLLSAIDIVR_SHIFT;
+                       pllsai_rate = stm32_clk_get_pllsai_rate(priv, PLLSAIR);
+
+                       return pllsai_rate / pllsaidivr_table[saidivr];
                }
                return (sysclk >> stm32_get_apb_shift(regs, APB2));