phy: fsl-imx8mp-usb: add support for phy tuning

Add USB PHY parameter tuning for USB certifications.

Reviewed-by: Haibo Chen <haibo.chen@nxp.com>
Signed-off-by: Li Jun <jun.li@nxp.com>
[j.zink: ported to v6.3-rc1 from NXP downstream repo + cleanups]
Signed-off-by: Johannes Zink <j.zink@pengutronix.de>
Link: https://lore.kernel.org/r/20230516-lustige-usb-phy-dinge-v2-2-3383a0de34ac@pengutronix.de
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/phy/freescale/phy-fsl-imx8mq-usb.c b/drivers/phy/freescale/phy-fsl-imx8mq-usb.c
index a29b4a6f7c249bae07e86eb466afd8fccb84d155..88826ceb72f8d36ee1bdd07d1aa50f33078a3e34 100644 (file)
--- a/drivers/phy/freescale/phy-fsl-imx8mq-usb.c
+++ b/drivers/phy/freescale/phy-fsl-imx8mq-usb.c
@@ -27,17 +27,231 @@
 #define PHY_CTRL2_TXENABLEN0           BIT(8)
 #define PHY_CTRL2_OTG_DISABLE          BIT(9)
 
+#define PHY_CTRL3                      0xc
+#define PHY_CTRL3_COMPDISTUNE_MASK     GENMASK(2, 0)
+#define PHY_CTRL3_TXPREEMP_TUNE_MASK   GENMASK(16, 15)
+#define PHY_CTRL3_TXRISE_TUNE_MASK     GENMASK(21, 20)
+#define PHY_CTRL3_TXVREF_TUNE_MASK     GENMASK(25, 22)
+#define PHY_CTRL3_TX_VBOOST_LEVEL_MASK GENMASK(31, 29)
+
+#define PHY_CTRL4                      0x10
+#define PHY_CTRL4_PCS_TX_DEEMPH_3P5DB_MASK     GENMASK(20, 15)
+
+#define PHY_CTRL5                      0x14
+#define PHY_CTRL5_DMPWD_OVERRIDE_SEL   BIT(23)
+#define PHY_CTRL5_DMPWD_OVERRIDE       BIT(22)
+#define PHY_CTRL5_DPPWD_OVERRIDE_SEL   BIT(21)
+#define PHY_CTRL5_DPPWD_OVERRIDE       BIT(20)
+#define PHY_CTRL5_PCS_TX_SWING_FULL_MASK       GENMASK(6, 0)
+
 #define PHY_CTRL6                      0x18
 #define PHY_CTRL6_ALT_CLK_EN           BIT(1)
 #define PHY_CTRL6_ALT_CLK_SEL          BIT(0)
 
+#define PHY_TUNE_DEFAULT               0xffffffff
+
 struct imx8mq_usb_phy {
        struct phy *phy;
        struct clk *clk;
        void __iomem *base;
        struct regulator *vbus;
+       u32 pcs_tx_swing_full;
+       u32 pcs_tx_deemph_3p5db;
+       u32 tx_vref_tune;
+       u32 tx_rise_tune;
+       u32 tx_preemp_amp_tune;
+       u32 tx_vboost_level;
+       u32 comp_dis_tune;
 };
 
+static u32 phy_tx_vref_tune_from_property(u32 percent)
+{
+       percent = clamp(percent, 94U, 124U);
+
+       return DIV_ROUND_CLOSEST(percent - 94U, 2);
+}
+
+static u32 phy_tx_rise_tune_from_property(u32 percent)
+{
+       switch (percent) {
+       case 0 ... 98:
+               return 3;
+       case 99:
+               return 2;
+       case 100 ... 101:
+               return 1;
+       default:
+               return 0;
+       }
+}
+
+static u32 phy_tx_preemp_amp_tune_from_property(u32 microamp)
+{
+       microamp = min(microamp, 1800U);
+
+       return microamp / 600;
+}
+
+static u32 phy_tx_vboost_level_from_property(u32 microvolt)
+{
+       switch (microvolt) {
+       case 0 ... 960:
+               return 0;
+       case 961 ... 1160:
+               return 2;
+       default:
+               return 3;
+       }
+}
+
+static u32 phy_pcs_tx_deemph_3p5db_from_property(u32 decibel)
+{
+       return min(decibel, 36U);
+}
+
+static u32 phy_comp_dis_tune_from_property(u32 percent)
+{
+       switch (percent) {
+       case 0 ... 92:
+               return 0;
+       case 93 ... 95:
+               return 1;
+       case 96 ... 97:
+               return 2;
+       case 98 ... 102:
+               return 3;
+       case 103 ... 105:
+               return 4;
+       case 106 ... 109:
+               return 5;
+       case 110 ... 113:
+               return 6;
+       default:
+               return 7;
+       }
+}
+static u32 phy_pcs_tx_swing_full_from_property(u32 percent)
+{
+       percent = min(percent, 100U);
+
+       return (percent * 127) / 100;
+}
+
+static void imx8m_get_phy_tuning_data(struct imx8mq_usb_phy *imx_phy)
+{
+       struct device *dev = imx_phy->phy->dev.parent;
+
+       if (device_property_read_u32(dev, "fsl,phy-tx-vref-tune-percent",
+                                    &imx_phy->tx_vref_tune))
+               imx_phy->tx_vref_tune = PHY_TUNE_DEFAULT;
+       else
+               imx_phy->tx_vref_tune =
+                       phy_tx_vref_tune_from_property(imx_phy->tx_vref_tune);
+
+       if (device_property_read_u32(dev, "fsl,phy-tx-rise-tune-percent",
+                                    &imx_phy->tx_rise_tune))
+               imx_phy->tx_rise_tune = PHY_TUNE_DEFAULT;
+       else
+               imx_phy->tx_rise_tune =
+                       phy_tx_rise_tune_from_property(imx_phy->tx_rise_tune);
+
+       if (device_property_read_u32(dev, "fsl,phy-tx-preemp-amp-tune-microamp",
+                                    &imx_phy->tx_preemp_amp_tune))
+               imx_phy->tx_preemp_amp_tune = PHY_TUNE_DEFAULT;
+       else
+               imx_phy->tx_preemp_amp_tune =
+                       phy_tx_preemp_amp_tune_from_property(imx_phy->tx_preemp_amp_tune);
+
+       if (device_property_read_u32(dev, "fsl,phy-tx-vboost-level-microvolt",
+                                    &imx_phy->tx_vboost_level))
+               imx_phy->tx_vboost_level = PHY_TUNE_DEFAULT;
+       else
+               imx_phy->tx_vboost_level =
+                       phy_tx_vboost_level_from_property(imx_phy->tx_vboost_level);
+
+       if (device_property_read_u32(dev, "fsl,phy-comp-dis-tune-percent",
+                                    &imx_phy->comp_dis_tune))
+               imx_phy->comp_dis_tune = PHY_TUNE_DEFAULT;
+       else
+               imx_phy->comp_dis_tune =
+                       phy_comp_dis_tune_from_property(imx_phy->comp_dis_tune);
+
+       if (device_property_read_u32(dev, "fsl,pcs-tx-deemph-3p5db-attenuation-db",
+                                    &imx_phy->pcs_tx_deemph_3p5db))
+               imx_phy->pcs_tx_deemph_3p5db = PHY_TUNE_DEFAULT;
+       else
+               imx_phy->pcs_tx_deemph_3p5db =
+                       phy_pcs_tx_deemph_3p5db_from_property(imx_phy->pcs_tx_deemph_3p5db);
+
+       if (device_property_read_u32(dev, "fsl,phy-pcs-tx-swing-full-percent",
+                                    &imx_phy->pcs_tx_swing_full))
+               imx_phy->pcs_tx_swing_full = PHY_TUNE_DEFAULT;
+       else
+               imx_phy->pcs_tx_swing_full =
+                       phy_pcs_tx_swing_full_from_property(imx_phy->pcs_tx_swing_full);
+}
+
+static void imx8m_phy_tune(struct imx8mq_usb_phy *imx_phy)
+{
+       u32 value;
+
+       /* PHY tuning */
+       if (imx_phy->pcs_tx_deemph_3p5db != PHY_TUNE_DEFAULT) {
+               value = readl(imx_phy->base + PHY_CTRL4);
+               value &= ~PHY_CTRL4_PCS_TX_DEEMPH_3P5DB_MASK;
+               value |= FIELD_PREP(PHY_CTRL4_PCS_TX_DEEMPH_3P5DB_MASK,
+                                  imx_phy->pcs_tx_deemph_3p5db);
+               writel(value, imx_phy->base + PHY_CTRL4);
+       }
+
+       if (imx_phy->pcs_tx_swing_full != PHY_TUNE_DEFAULT) {
+               value = readl(imx_phy->base + PHY_CTRL5);
+               value |= FIELD_PREP(PHY_CTRL5_PCS_TX_SWING_FULL_MASK,
+                                  imx_phy->pcs_tx_swing_full);
+               writel(value, imx_phy->base + PHY_CTRL5);
+       }
+
+       if ((imx_phy->tx_vref_tune & imx_phy->tx_rise_tune &
+            imx_phy->tx_preemp_amp_tune & imx_phy->comp_dis_tune &
+            imx_phy->tx_vboost_level) == PHY_TUNE_DEFAULT)
+               /* If all are the default values, no need update. */
+               return;
+
+       value = readl(imx_phy->base + PHY_CTRL3);
+
+       if (imx_phy->tx_vref_tune != PHY_TUNE_DEFAULT) {
+               value &= ~PHY_CTRL3_TXVREF_TUNE_MASK;
+               value |= FIELD_PREP(PHY_CTRL3_TXVREF_TUNE_MASK,
+                                  imx_phy->tx_vref_tune);
+       }
+
+       if (imx_phy->tx_rise_tune != PHY_TUNE_DEFAULT) {
+               value &= ~PHY_CTRL3_TXRISE_TUNE_MASK;
+               value |= FIELD_PREP(PHY_CTRL3_TXRISE_TUNE_MASK,
+                                   imx_phy->tx_rise_tune);
+       }
+
+       if (imx_phy->tx_preemp_amp_tune != PHY_TUNE_DEFAULT) {
+               value &= ~PHY_CTRL3_TXPREEMP_TUNE_MASK;
+               value |= FIELD_PREP(PHY_CTRL3_TXPREEMP_TUNE_MASK,
+                               imx_phy->tx_preemp_amp_tune);
+       }
+
+       if (imx_phy->comp_dis_tune != PHY_TUNE_DEFAULT) {
+               value &= ~PHY_CTRL3_COMPDISTUNE_MASK;
+               value |= FIELD_PREP(PHY_CTRL3_COMPDISTUNE_MASK,
+                                   imx_phy->comp_dis_tune);
+       }
+
+       if (imx_phy->tx_vboost_level != PHY_TUNE_DEFAULT) {
+               value &= ~PHY_CTRL3_TX_VBOOST_LEVEL_MASK;
+               value |= FIELD_PREP(PHY_CTRL3_TX_VBOOST_LEVEL_MASK,
+                                   imx_phy->tx_vboost_level);
+       }
+
+       writel(value, imx_phy->base + PHY_CTRL3);
+}
+
 static int imx8mq_usb_phy_init(struct phy *phy)
 {
        struct imx8mq_usb_phy *imx_phy = phy_get_drvdata(phy);
@@ -99,6 +313,8 @@ static int imx8mp_usb_phy_init(struct phy *phy)
        value &= ~(PHY_CTRL1_RESET | PHY_CTRL1_ATERESET);
        writel(value, imx_phy->base + PHY_CTRL1);
 
+       imx8m_phy_tune(imx_phy);
+
        return 0;
 }
 
@@ -182,6 +398,8 @@ static int imx8mq_usb_phy_probe(struct platform_device *pdev)
 
        phy_set_drvdata(imx_phy->phy, imx_phy);
 
+       imx8m_get_phy_tuning_data(imx_phy);
+
        phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
 
        return PTR_ERR_OR_ZERO(phy_provider);