phy: exynos5-usbdrd: set ref clk freq in exynos850_usbdrd_utmi_init()

While commit 255ec38 ("phy: exynos5-usbdrd: Add 26MHz ref clk
support") correctly states that CLKRSTCTRL[7:5] doesn't need to be set
on modern Exynos platforms, SSPPLLCTL[2:0] should be programmed with
the frequency of the reference clock for the USB2.0 phy instead.

I stumbled across this while adding support for the Google Tensor
gs101, but this should apply to E850 just the same.

Do so.

Signed-off-by: André Draszik <andre.draszik@linaro.org>
Reviewed-by: Peter Griffin <peter.griffin@linaro.org>
Link: https://lore.kernel.org/r/20240507-samsung-usb-phy-fixes-v1-5-4ccba5afa7cc@linaro.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Author: andred

drivers/phy/samsung/phy-exynos5-usbdrd.c

@@ -8,6 +8,7 @@
  * Author: Vivek Gautam <gautam.vivek@samsung.com>
  */
 
+#include <linux/bitfield.h>
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/io.h>
@@ -141,6 +142,9 @@
 #define CLKRST_PORT_RST				BIT(1)
 #define CLKRST_LINK_SW_RST			BIT(0)
 
+#define EXYNOS850_DRD_SSPPLLCTL			0x30
+#define SSPPLLCTL_FSEL				GENMASK(2, 0)
+
 #define EXYNOS850_DRD_UTMI			0x50
 #define UTMI_FORCE_VBUSVALID			BIT(5)
 #define UTMI_FORCE_BVALID			BIT(4)
@@ -773,6 +777,31 @@ static void exynos850_usbdrd_utmi_init(struct exynos5_usbdrd_phy *phy_drd)
 	reg |= HSP_VBUSVLDEXT | HSP_VBUSVLDEXTSEL;
 	writel(reg, regs_base + EXYNOS850_DRD_HSP);
 
+	reg = readl(regs_base + EXYNOS850_DRD_SSPPLLCTL);
+	reg &= ~SSPPLLCTL_FSEL;
+	switch (phy_drd->extrefclk) {
+	case EXYNOS5_FSEL_50MHZ:
+		reg |= FIELD_PREP_CONST(SSPPLLCTL_FSEL, 7);
+		break;
+	case EXYNOS5_FSEL_26MHZ:
+		reg |= FIELD_PREP_CONST(SSPPLLCTL_FSEL, 6);
+		break;
+	case EXYNOS5_FSEL_24MHZ:
+		reg |= FIELD_PREP_CONST(SSPPLLCTL_FSEL, 2);
+		break;
+	case EXYNOS5_FSEL_20MHZ:
+		reg |= FIELD_PREP_CONST(SSPPLLCTL_FSEL, 1);
+		break;
+	case EXYNOS5_FSEL_19MHZ2:
+		reg |= FIELD_PREP_CONST(SSPPLLCTL_FSEL, 0);
+		break;
+	default:
+		dev_warn(phy_drd->dev, "unsupported ref clk: %#.2x\n",
+			 phy_drd->extrefclk);
+		break;
+	}
+	writel(reg, regs_base + EXYNOS850_DRD_SSPPLLCTL);
+
 	/* Power up PHY analog blocks */
 	reg = readl(regs_base + EXYNOS850_DRD_HSP_TEST);
 	reg &= ~HSP_TEST_SIDDQ;