[PATCH v2 2/5] phy: phy-mtk-tphy: add support mt8195

[Chunfeng Yun]

The T-PHY controller is designed to use use PLL integer mode, but
in fact use fractional mode for some ones on mt8195 by mistake,
this causes signal degradation (e.g. eye diagram test fail), fix
it by switching PLL to 26Mhz from default 48Mhz to improve signal
quality.

Signed-off-by: Chunfeng Yun <chunfeng.yun at mediatek.com>
---
v2: use FIELD_PREP() macro
---
 drivers/phy/phy-mtk-tphy.c | 91 +++++++++++++++++++++++++++++++++-----
 1 file changed, 81 insertions(+), 10 deletions(-)

diff --git a/drivers/phy/phy-mtk-tphy.c b/drivers/phy/phy-mtk-tphy.c
index 24e6124b76..1883f9f83e 100644
--- a/drivers/phy/phy-mtk-tphy.c
+++ b/drivers/phy/phy-mtk-tphy.c
@@ -44,8 +44,12 @@
 
 #define U3P_USBPHYACR0			0x000
 #define PA0_RG_U2PLL_FORCE_ON		BIT(15)
+#define PA0_USB20_PLL_PREDIV		GENMASK(7, 6)
 #define PA0_RG_USB20_INTR_EN		BIT(5)
 
+#define U3P_USBPHYACR2			0x008
+#define PA2_RG_U2PLL_BW			GENMASK(21, 19)
+
 #define U3P_USBPHYACR5			0x014
 #define PA5_RG_U2_HSTX_SRCAL_EN		BIT(15)
 #define PA5_RG_U2_HSTX_SRCTRL		GENMASK(14, 12)
@@ -62,6 +66,14 @@
 #define P2C_U2_GPIO_CTR_MSK	\
 		(P2C_RG_USB20_GPIO_CTL | P2C_USB20_GPIO_MODE)
 
+#define U3P_U2PHYA_RESV			0x030
+#define P2R_RG_U2PLL_FBDIV_26M		0x1bb13b
+#define P2R_RG_U2PLL_FBDIV_48M		0x3c0000
+
+#define U3P_U2PHYA_RESV1		0x044
+#define P2R_RG_U2PLL_REFCLK_SEL		BIT(5)
+#define P2R_RG_U2PLL_FRA_EN		BIT(3)
+
 #define U3P_U2PHYDTM0			0x068
 #define P2C_FORCE_UART_EN		BIT(26)
 #define P2C_FORCE_DATAIN		BIT(23)
@@ -202,6 +214,17 @@ enum mtk_phy_version {
 	MTK_TPHY_V2,
 };
 
+struct tphy_pdata {
+	enum mtk_phy_version version;
+
+	/*
+	 * workaround only for mt8195:
+	 * u2phy should use integer mode instead of fractional mode of
+	 * 48M PLL, fix it by switching PLL to 26M from default 48M
+	 */
+	bool sw_pll_48m_to_26m;
+};
+
 struct u2phy_banks {
 	void __iomem *misc;
 	void __iomem *fmreg;
@@ -232,11 +255,32 @@ struct mtk_phy_instance {
 struct mtk_tphy {
 	struct udevice *dev;
 	void __iomem *sif_base;
-	enum mtk_phy_version version;
+	const struct tphy_pdata *pdata;
 	struct mtk_phy_instance **phys;
 	int nphys;
 };
 
+/* workaround only for mt8195 */
+static void u2_phy_pll_26m_set(struct mtk_tphy *tphy,
+			       struct mtk_phy_instance *instance)
+{
+	struct u2phy_banks *u2_banks = &instance->u2_banks;
+
+	if (!tphy->pdata->sw_pll_48m_to_26m)
+		return;
+
+	clrsetbits_le32(u2_banks->com + U3P_USBPHYACR0, PA0_USB20_PLL_PREDIV,
+			FIELD_PREP(PA0_USB20_PLL_PREDIV, 0));
+
+	clrsetbits_le32(u2_banks->com + U3P_USBPHYACR2, PA2_RG_U2PLL_BW,
+			FIELD_PREP(PA2_RG_U2PLL_BW, 3));
+
+	writel(P2R_RG_U2PLL_FBDIV_26M, u2_banks->com + U3P_U2PHYA_RESV);
+
+	setbits_le32(u2_banks->com + U3P_U2PHYA_RESV1,
+		     P2R_RG_U2PLL_FRA_EN | P2R_RG_U2PLL_REFCLK_SEL);
+}
+
 static void u2_phy_instance_init(struct mtk_tphy *tphy,
 				 struct mtk_phy_instance *instance)
 {
@@ -266,6 +310,8 @@ static void u2_phy_instance_init(struct mtk_tphy *tphy,
 			PA5_RG_U2_HSTX_SRCTRL,
 			FIELD_PREP(PA5_RG_U2_HSTX_SRCTRL, 4));
 
+	u2_phy_pll_26m_set(tphy, instance);
+
 	dev_dbg(tphy->dev, "%s(%d)\n", __func__, instance->index);
 }
 
@@ -350,7 +396,7 @@ static void pcie_phy_instance_init(struct mtk_tphy *tphy,
 {
 	struct u3phy_banks *u3_banks = &instance->u3_banks;
 
-	if (tphy->version != MTK_TPHY_V1)
+	if (tphy->pdata->version != MTK_TPHY_V1)
 		return;
 
 	clrsetbits_le32(u3_banks->phya + U3P_U3_PHYA_DA_REG0,
@@ -634,11 +680,14 @@ static int mtk_phy_xlate(struct phy *phy,
 		return -EINVAL;
 	}
 
-	if (tphy->version == MTK_TPHY_V1) {
+	switch (tphy->pdata->version) {
+	case MTK_TPHY_V1:
 		phy_v1_banks_init(tphy, instance);
-	} else if (tphy->version == MTK_TPHY_V2) {
+		break;
+	case MTK_TPHY_V2:
 		phy_v2_banks_init(tphy, instance);
-	} else {
+		break;
+	default:
 		dev_err(phy->dev, "phy version is not supported\n");
 		return -EINVAL;
 	}
@@ -668,13 +717,12 @@ static int mtk_tphy_probe(struct udevice *dev)
 		return -ENOMEM;
 
 	tphy->dev = dev;
-	tphy->version = dev_get_driver_data(dev);
+	tphy->pdata = (void *)dev_get_driver_data(dev);
 
 	/* v1 has shared banks for usb/pcie mode, */
 	/* but not for sata mode */
-	if (tphy->version == MTK_TPHY_V1) {
+	if (tphy->pdata->version == MTK_TPHY_V1)
 		tphy->sif_base = dev_read_addr_ptr(dev);
-	}
 
 	dev_for_each_subnode(subnode, dev) {
 		struct mtk_phy_instance *instance;
@@ -709,9 +757,32 @@ static int mtk_tphy_probe(struct udevice *dev)
 	return 0;
 }
 
+static struct tphy_pdata tphy_v1_pdata = {
+	.version = MTK_TPHY_V1,
+};
+
+static struct tphy_pdata tphy_v2_pdata = {
+	.version = MTK_TPHY_V2,
+};
+
+static struct tphy_pdata mt8195_pdata = {
+	.version = MTK_TPHY_V2,
+	.sw_pll_48m_to_26m = true,
+};
+
 static const struct udevice_id mtk_tphy_id_table[] = {
-	{ .compatible = "mediatek,generic-tphy-v1", .data = MTK_TPHY_V1, },
-	{ .compatible = "mediatek,generic-tphy-v2", .data = MTK_TPHY_V2, },
+	{
+		.compatible = "mediatek,generic-tphy-v1",
+		.data = (ulong)&tphy_v1_pdata,
+	},
+	{
+		.compatible = "mediatek,generic-tphy-v2",
+		.data = (ulong)&tphy_v2_pdata,
+	},
+	{
+		.compatible = "mediatek,mt8195-tphy",
+		.data = (ulong)&mt8195_pdata,
+	},
 	{ }
 };
 
-- 
2.18.0