clk: stm32: retrieve external oscillator frequency from DT

All current STM32F4 supported boards uses a 8MHz external oscillator.
All current STM32F7 supported boards uses a 25MHz external oscillator.

In order to introduce the new stm32f429-evaluation board which uses a
25MHz external oscillator without creating a dedicated struct
stm32_clk_info for this board, retrieve the external oscillator
frequency from DT and set pll_m accordingly to obtain 1MHz for the VCO.

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

diff --git a/drivers/clk/clk_stm32f.c b/drivers/clk/clk_stm32f.c
index 63116e0bac35c73df17139caee65f6ef94c45a3a..ebe1ce60c1969e1804f5165cd49d09f0f2ac977e 100644 (file)
--- a/drivers/clk/clk_stm32f.c
+++ b/drivers/clk/clk_stm32f.c
@@ -93,10 +93,9 @@ enum periph_clock {
        STMMAC_CLOCK_CFG,
 };
 
-struct stm32_clk_info stm32f4_clk_info = {
+static const struct stm32_clk_info stm32f4_clk_info = {
        /* 180 MHz */
        .sys_pll_psc = {
-               .pll_m = 8,
                .pll_n = 360,
                .pll_p = 2,
                .pll_q = 8,
@@ -108,10 +107,9 @@ struct stm32_clk_info stm32f4_clk_info = {
        .v2 = false,
 };
 
-struct stm32_clk_info stm32f7_clk_info = {
+static const struct stm32_clk_info stm32f7_clk_info = {
        /* 200 MHz */
        .sys_pll_psc = {
-               .pll_m = 25,
                .pll_n = 400,
                .pll_p = 2,
                .pll_q = 8,
@@ -126,7 +124,8 @@ struct stm32_clk_info stm32f7_clk_info = {
 struct stm32_clk {
        struct stm32_rcc_regs *base;
        struct stm32_pwr_regs *pwr_regs;
-       struct stm32_clk_info *info;
+       struct stm32_clk_info info;
+       unsigned long hse_rate;
 };
 
 static int configure_clocks(struct udevice *dev)
@@ -134,7 +133,7 @@ static int configure_clocks(struct udevice *dev)
        struct stm32_clk *priv = dev_get_priv(dev);
        struct stm32_rcc_regs *regs = priv->base;
        struct stm32_pwr_regs *pwr = priv->pwr_regs;
-       struct pll_psc sys_pll_psc = priv->info->sys_pll_psc;
+       struct pll_psc *sys_pll_psc = &priv->info.sys_pll_psc;
        u32 pllsaicfgr = 0;
 
        /* Reset RCC configuration */
@@ -152,20 +151,20 @@ static int configure_clocks(struct udevice *dev)
                ;
 
        setbits_le32(&regs->cfgr, ((
-               sys_pll_psc.ahb_psc << RCC_CFGR_HPRE_SHIFT)
-               | (sys_pll_psc.apb1_psc << RCC_CFGR_PPRE1_SHIFT)
-               | (sys_pll_psc.apb2_psc << RCC_CFGR_PPRE2_SHIFT)));
+               sys_pll_psc->ahb_psc << RCC_CFGR_HPRE_SHIFT)
+               | (sys_pll_psc->apb1_psc << RCC_CFGR_PPRE1_SHIFT)
+               | (sys_pll_psc->apb2_psc << RCC_CFGR_PPRE2_SHIFT)));
 
        /* Configure the main PLL */
        setbits_le32(&regs->pllcfgr, RCC_PLLCFGR_PLLSRC); /* pll source HSE */
        clrsetbits_le32(&regs->pllcfgr, RCC_PLLCFGR_PLLM_MASK,
-                       sys_pll_psc.pll_m << RCC_PLLCFGR_PLLM_SHIFT);
+                       sys_pll_psc->pll_m << RCC_PLLCFGR_PLLM_SHIFT);
        clrsetbits_le32(&regs->pllcfgr, RCC_PLLCFGR_PLLN_MASK,
-                       sys_pll_psc.pll_n << RCC_PLLCFGR_PLLN_SHIFT);
+                       sys_pll_psc->pll_n << RCC_PLLCFGR_PLLN_SHIFT);
        clrsetbits_le32(&regs->pllcfgr, RCC_PLLCFGR_PLLP_MASK,
-                       ((sys_pll_psc.pll_p >> 1) - 1) << RCC_PLLCFGR_PLLP_SHIFT);
+                       ((sys_pll_psc->pll_p >> 1) - 1) << RCC_PLLCFGR_PLLP_SHIFT);
        clrsetbits_le32(&regs->pllcfgr, RCC_PLLCFGR_PLLQ_MASK,
-                       sys_pll_psc.pll_q << RCC_PLLCFGR_PLLQ_SHIFT);
+                       sys_pll_psc->pll_q << RCC_PLLCFGR_PLLQ_SHIFT);
 
        /* Configure the SAI PLL to get a 48 MHz source */
        pllsaicfgr = RCC_PLLSAICFGR_PLLSAIR_2 | RCC_PLLSAICFGR_PLLSAIQ_4 |
@@ -178,7 +177,7 @@ static int configure_clocks(struct udevice *dev)
        while (!(readl(&regs->cr) & RCC_CR_PLLRDY))
                ;
 
-       if (priv->info->v2) { /*stm32f7 case */
+       if (priv->info.v2) { /*stm32f7 case */
                /* select PLLSAI as 48MHz clock source */
                setbits_le32(&regs->dckcfgr2, RCC_DCKCFGRX_CK48MSEL);
 
@@ -202,7 +201,7 @@ static int configure_clocks(struct udevice *dev)
 
        setbits_le32(&regs->apb1enr, RCC_APB1ENR_PWREN);
 
-       if (priv->info->has_overdrive) {
+       if (priv->info.has_overdrive) {
                /*
                 * Enable high performance mode
                 * System frequency up to 200 MHz
@@ -241,7 +240,7 @@ static unsigned long stm32_clk_pll48clk_rate(struct stm32_clk *priv,
        pllq = (readl(&regs->pllcfgr) & RCC_PLLCFGR_PLLQ_MASK)
               >> RCC_PLLCFGR_PLLQ_SHIFT;
 
-       if (priv->info->v2) /*stm32f7 case */
+       if (priv->info.v2) /*stm32f7 case */
                pllsai = readl(&regs->dckcfgr2) & RCC_DCKCFGRX_CK48MSEL;
        else
                pllsai = readl(&regs->dckcfgr) & RCC_DCKCFGRX_CK48MSEL;
@@ -253,7 +252,7 @@ static unsigned long stm32_clk_pll48clk_rate(struct stm32_clk *priv,
                        >> RCC_PLLSAICFGR_PLLSAIN_SHIFT);
                pllsaip = ((((readl(&regs->pllsaicfgr) & RCC_PLLCFGR_PLLSAIP_MASK)
                        >> RCC_PLLSAICFGR_PLLSAIP_SHIFT) + 1) << 1);
-               return ((CONFIG_STM32_HSE_HZ / pllm) * pllsain) / pllsaip;
+               return ((priv->hse_rate / pllm) * pllsain) / pllsaip;
        }
        /* PLL48CLK is selected from PLLQ */
        return sysclk / pllq;
@@ -281,7 +280,7 @@ static unsigned long stm32_clk_get_rate(struct clk *clk)
                        >> RCC_PLLCFGR_PLLN_SHIFT);
                pllp = ((((readl(&regs->pllcfgr) & RCC_PLLCFGR_PLLP_MASK)
                        >> RCC_PLLCFGR_PLLP_SHIFT) + 1) << 1);
-               sysclk = ((CONFIG_STM32_HSE_HZ / pllm) * plln) / pllp;
+               sysclk = ((priv->hse_rate / pllm) * plln) / pllp;
        } else {
                return -EINVAL;
        }
@@ -372,6 +371,8 @@ void clock_setup(int peripheral)
 static int stm32_clk_probe(struct udevice *dev)
 {
        struct ofnode_phandle_args args;
+       struct udevice *fixed_clock_dev = NULL;
+       struct clk clk;
        int err;
 
        debug("%s\n", __func__);
@@ -387,16 +388,51 @@ static int stm32_clk_probe(struct udevice *dev)
 
        switch (dev_get_driver_data(dev)) {
        case STM32F4:
-               priv->info = &stm32f4_clk_info;
+               memcpy(&priv->info, &stm32f4_clk_info,
+                      sizeof(struct stm32_clk_info));
                break;
        case STM32F7:
-               priv->info = &stm32f7_clk_info;
+               memcpy(&priv->info, &stm32f7_clk_info,
+                      sizeof(struct stm32_clk_info));
                break;
        default:
                return -EINVAL;
        }
 
-       if (priv->info->has_overdrive) {
+       /* retrieve HSE frequency (external oscillator) */
+       err = uclass_get_device_by_name(UCLASS_CLK, "clk-hse",
+                                       &fixed_clock_dev);
+
+       if (err) {
+               pr_err("Can't find fixed clock (%d)", err);
+               return err;
+       }
+
+       err = clk_request(fixed_clock_dev, &clk);
+       if (err) {
+               pr_err("Can't request %s clk (%d)", fixed_clock_dev->name,
+                      err);
+               return err;
+       }
+
+       /*
+        * set pllm factor accordingly to the external oscillator
+        * frequency (HSE). For STM32F4 and STM32F7, we want VCO
+        * freq at 1MHz
+        * if input PLL frequency is 25Mhz, divide it by 25
+        */
+       clk.id = 0;
+       priv->hse_rate = clk_get_rate(&clk);
+
+       if (priv->hse_rate < 1000000) {
+               pr_err("%s: unexpected HSE clock rate = %ld \"n", __func__,
+                      priv->hse_rate);
+               return -EINVAL;
+       }
+
+       priv->info.sys_pll_psc.pll_m = priv->hse_rate / 1000000;
+
+       if (priv->info.has_overdrive) {
                err = dev_read_phandle_with_args(dev, "st,syscfg", NULL, 0, 0,
                                                 &args);
                if (err) {