phy: freescale: imx8m-pcie: Refine i.MX8MM PCIe PHY driver

To make it more flexible and easy to expand. Refine i.MX8MM PCIe PHY
driver.
- Use gpr compatible string to avoid the codes duplications when add
  another platform PCIe PHY support.
- Re-arrange the codes to let it more flexible and easy to expand.
No functional change. Re-arrange the TX tuning, since internal registers
can be wrote through APB interface before assertion of CMN_RST.

Signed-off-by: Richard Zhu <[email protected]>
Signed-off-by: Lucas Stach <[email protected]>
Tested-by: Marek Vasut <[email protected]>
Tested-by: Richard Leitner <[email protected]>
Tested-by: Alexander Stein <[email protected]>
Reviewed-by: Lucas Stach <[email protected]>
Reviewed-by: Ahmad Fatoum <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Vinod Koul <[email protected]>

Author: Richard Zhu

drivers/phy/freescale/phy-fsl-imx8m-pcie.c

@@ -11,6 +11,7 @@
 #include <linux/mfd/syscon.h>
 #include <linux/mfd/syscon/imx7-iomuxc-gpr.h>
 #include <linux/module.h>
+#include <linux/of_device.h>
 #include <linux/phy/phy.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
@@ -45,6 +46,15 @@
 #define IMX8MM_GPR_PCIE_SSC_EN		BIT(16)
 #define IMX8MM_GPR_PCIE_AUX_EN_OVERRIDE	BIT(9)
 
+enum imx8_pcie_phy_type {
+	IMX8MM,
+};
+
+struct imx8_pcie_phy_drvdata {
+	const	char			*gpr;
+	enum	imx8_pcie_phy_type	variant;
+};
+
 struct imx8_pcie_phy {
 	void __iomem		*base;
 	struct clk		*clk;
@@ -55,6 +65,7 @@ struct imx8_pcie_phy {
 	u32			tx_deemph_gen1;
 	u32			tx_deemph_gen2;
 	bool			clkreq_unused;
+	const struct imx8_pcie_phy_drvdata	*drvdata;
 };
 
 static int imx8_pcie_phy_power_on(struct phy *phy)
@@ -66,31 +77,17 @@ static int imx8_pcie_phy_power_on(struct phy *phy)
 	reset_control_assert(imx8_phy->reset);
 
 	pad_mode = imx8_phy->refclk_pad_mode;
-	/* Set AUX_EN_OVERRIDE 1'b0, when the CLKREQ# isn't hooked */
-	regmap_update_bits(imx8_phy->iomuxc_gpr, IOMUXC_GPR14,
-			   IMX8MM_GPR_PCIE_AUX_EN_OVERRIDE,
-			   imx8_phy->clkreq_unused ?
-			   0 : IMX8MM_GPR_PCIE_AUX_EN_OVERRIDE);
-	regmap_update_bits(imx8_phy->iomuxc_gpr, IOMUXC_GPR14,
-			   IMX8MM_GPR_PCIE_AUX_EN,
-			   IMX8MM_GPR_PCIE_AUX_EN);
-	regmap_update_bits(imx8_phy->iomuxc_gpr, IOMUXC_GPR14,
-			   IMX8MM_GPR_PCIE_POWER_OFF, 0);
-	regmap_update_bits(imx8_phy->iomuxc_gpr, IOMUXC_GPR14,
-			   IMX8MM_GPR_PCIE_SSC_EN, 0);
-
-	regmap_update_bits(imx8_phy->iomuxc_gpr, IOMUXC_GPR14,
-			   IMX8MM_GPR_PCIE_REF_CLK_SEL,
-			   pad_mode == IMX8_PCIE_REFCLK_PAD_INPUT ?
-			   IMX8MM_GPR_PCIE_REF_CLK_EXT :
-			   IMX8MM_GPR_PCIE_REF_CLK_PLL);
-	usleep_range(100, 200);
-
-	/* Do the PHY common block reset */
-	regmap_update_bits(imx8_phy->iomuxc_gpr, IOMUXC_GPR14,
-			   IMX8MM_GPR_PCIE_CMN_RST,
-			   IMX8MM_GPR_PCIE_CMN_RST);
-	usleep_range(200, 500);
+	switch (imx8_phy->drvdata->variant) {
+	case IMX8MM:
+		/* Tune PHY de-emphasis setting to pass PCIe compliance. */
+		if (imx8_phy->tx_deemph_gen1)
+			writel(imx8_phy->tx_deemph_gen1,
+			       imx8_phy->base + PCIE_PHY_TRSV_REG5);
+		if (imx8_phy->tx_deemph_gen2)
+			writel(imx8_phy->tx_deemph_gen2,
+			       imx8_phy->base + PCIE_PHY_TRSV_REG6);
+		break;
+	}
 
 	if (pad_mode == IMX8_PCIE_REFCLK_PAD_INPUT ||
 	    pad_mode == IMX8_PCIE_REFCLK_PAD_UNUSED) {
@@ -118,15 +115,37 @@ static int imx8_pcie_phy_power_on(struct phy *phy)
 		       imx8_phy->base + IMX8MM_PCIE_PHY_CMN_REG065);
 	}
 
-	/* Tune PHY de-emphasis setting to pass PCIe compliance. */
-	if (imx8_phy->tx_deemph_gen1)
-		writel(imx8_phy->tx_deemph_gen1,
-		       imx8_phy->base + PCIE_PHY_TRSV_REG5);
-	if (imx8_phy->tx_deemph_gen2)
-		writel(imx8_phy->tx_deemph_gen2,
-		       imx8_phy->base + PCIE_PHY_TRSV_REG6);
+	/* Set AUX_EN_OVERRIDE 1'b0, when the CLKREQ# isn't hooked */
+	regmap_update_bits(imx8_phy->iomuxc_gpr, IOMUXC_GPR14,
+			   IMX8MM_GPR_PCIE_AUX_EN_OVERRIDE,
+			   imx8_phy->clkreq_unused ?
+			   0 : IMX8MM_GPR_PCIE_AUX_EN_OVERRIDE);
+	regmap_update_bits(imx8_phy->iomuxc_gpr, IOMUXC_GPR14,
+			   IMX8MM_GPR_PCIE_AUX_EN,
+			   IMX8MM_GPR_PCIE_AUX_EN);
+	regmap_update_bits(imx8_phy->iomuxc_gpr, IOMUXC_GPR14,
+			   IMX8MM_GPR_PCIE_POWER_OFF, 0);
+	regmap_update_bits(imx8_phy->iomuxc_gpr, IOMUXC_GPR14,
+			   IMX8MM_GPR_PCIE_SSC_EN, 0);
 
-	reset_control_deassert(imx8_phy->reset);
+	regmap_update_bits(imx8_phy->iomuxc_gpr, IOMUXC_GPR14,
+			   IMX8MM_GPR_PCIE_REF_CLK_SEL,
+			   pad_mode == IMX8_PCIE_REFCLK_PAD_INPUT ?
+			   IMX8MM_GPR_PCIE_REF_CLK_EXT :
+			   IMX8MM_GPR_PCIE_REF_CLK_PLL);
+	usleep_range(100, 200);
+
+	/* Do the PHY common block reset */
+	regmap_update_bits(imx8_phy->iomuxc_gpr, IOMUXC_GPR14,
+			   IMX8MM_GPR_PCIE_CMN_RST,
+			   IMX8MM_GPR_PCIE_CMN_RST);
+
+	switch (imx8_phy->drvdata->variant) {
+	case IMX8MM:
+		reset_control_deassert(imx8_phy->reset);
+		usleep_range(200, 500);
+		break;
+	}
 
 	/* Polling to check the phy is ready or not. */
 	ret = readl_poll_timeout(imx8_phy->base + IMX8MM_PCIE_PHY_CMN_REG075,
@@ -157,6 +176,17 @@ static const struct phy_ops imx8_pcie_phy_ops = {
 	.owner		= THIS_MODULE,
 };
 
+static const struct imx8_pcie_phy_drvdata imx8mm_drvdata = {
+	.gpr = "fsl,imx8mm-iomuxc-gpr",
+	.variant = IMX8MM,
+};
+
+static const struct of_device_id imx8_pcie_phy_of_match[] = {
+	{.compatible = "fsl,imx8mm-pcie-phy", .data = &imx8mm_drvdata, },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, imx8_pcie_phy_of_match);
+
 static int imx8_pcie_phy_probe(struct platform_device *pdev)
 {
 	struct phy_provider *phy_provider;
@@ -169,6 +199,8 @@ static int imx8_pcie_phy_probe(struct platform_device *pdev)
 	if (!imx8_phy)
 		return -ENOMEM;
 
+	imx8_phy->drvdata = of_device_get_match_data(dev);
+
 	/* get PHY refclk pad mode */
 	of_property_read_u32(np, "fsl,refclk-pad-mode",
 			     &imx8_phy->refclk_pad_mode);
@@ -194,7 +226,7 @@ static int imx8_pcie_phy_probe(struct platform_device *pdev)
 
 	/* Grab GPR config register range */
 	imx8_phy->iomuxc_gpr =
-		 syscon_regmap_lookup_by_compatible("fsl,imx6q-iomuxc-gpr");
+		 syscon_regmap_lookup_by_compatible(imx8_phy->drvdata->gpr);
 	if (IS_ERR(imx8_phy->iomuxc_gpr)) {
 		dev_err(dev, "unable to find iomuxc registers\n");
 		return PTR_ERR(imx8_phy->iomuxc_gpr);
@@ -222,12 +254,6 @@ static int imx8_pcie_phy_probe(struct platform_device *pdev)
 	return PTR_ERR_OR_ZERO(phy_provider);
 }
 
-static const struct of_device_id imx8_pcie_phy_of_match[] = {
-	{.compatible = "fsl,imx8mm-pcie-phy",},
-	{ },
-};
-MODULE_DEVICE_TABLE(of, imx8_pcie_phy_of_match);
-
 static struct platform_driver imx8_pcie_phy_driver = {
 	.probe	= imx8_pcie_phy_probe,
 	.driver = {