[PATCH 5/5] phy: exynos5-usbdrd: set ref clk freq in exynos850_usbdrd_utmi_init()

[André Draszik]

While commit 255ec3879dd4 ("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.

Fixes: 691525074db9 ("phy: exynos5-usbdrd: Add Exynos850 support")
Signed-off-by: André Draszik <andre.draszik at linaro.org>

---
Feel free to drop the Fixes: if you think that is unwarranted here.

v2: add missing bitfield.h include (seems this is implied on some
    platforms, but not on others)
---
 drivers/phy/samsung/phy-exynos5-usbdrd.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/drivers/phy/samsung/phy-exynos5-usbdrd.c b/drivers/phy/samsung/phy-exynos5-usbdrd.c
index 1da7a4881f72..15be966b50ae 100644
--- a/drivers/phy/samsung/phy-exynos5-usbdrd.c
+++ b/drivers/phy/samsung/phy-exynos5-usbdrd.c
@@ -8,6 +8,7 @@
  * Author: Vivek Gautam <gautam.vivek at 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;

-- 
2.45.0.rc1.225.g2a3ae87e7f-goog