-----Original Message-----
From: Lucas Stach <l.stach@pengutronix.de>
Sent: 2022年8月30日 21:07
To: Hongxing Zhu <hongxing.zhu@nxp.com>; p.zabel@pengutronix.de;
bhelgaas@google.com; lorenzo.pieralisi@arm.com; robh@kernel.org;
shawnguo@kernel.org; vkoul@kernel.org; alexander.stein@ew.tq-group.com;
marex@denx.de; richard.leitner@linux.dev
Cc: linux-phy@lists.infradead.org; devicetree@vger.kernel.org;
linux-pci@vger.kernel.org; linux-arm-kernel@lists.infradead.org;
linux-kernel@vger.kernel.org; kernel@pengutronix.de; dl-linux-imx
[off-list ref]
Subject: Re: [PATCH v5 6/7] phy: freescale: imx8m-pcie: Add iMX8MP PCIe PHY
support

Am Dienstag, dem 30.08.2022 um 15:46 +0800 schrieb Richard Zhu:

quoted

Add i.MX8MP PCIe PHY support.

Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Tested-by: Marek Vasut <marex@denx.de>
Tested-by: Richard Leitner <richard.leitner@skidata.com>
Tested-by: Alexander Stein <redacted>
---
 drivers/phy/freescale/phy-fsl-imx8m-pcie.c | 137
+++++++++++++--------
 1 file changed, 89 insertions(+), 48 deletions(-)

diff --git a/drivers/phy/freescale/phy-fsl-imx8m-pcie.c

b/drivers/phy/freescale/phy-fsl-imx8m-pcie.c
index ad7d2edfc414..c76e3a1a5f51 100644

--- a/drivers/phy/freescale/phy-fsl-imx8m-pcie.c
+++ b/drivers/phy/freescale/phy-fsl-imx8m-pcie.c

@@ -11,6 +11,9 @@
 #include <linux/mfd/syscon.h>
 #include <linux/mfd/syscon/imx7-iomuxc-gpr.h>
 #include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/of_device.h>
 #include <linux/phy/phy.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>

@@ -31,12 +34,10 @@
 #define IMX8MM_PCIE_PHY_CMN_REG065	0x194
 #define  ANA_AUX_RX_TERM		(BIT(7) | BIT(4))
 #define  ANA_AUX_TX_LVL			GENMASK(3, 0)
-#define IMX8MM_PCIE_PHY_CMN_REG75	0x1D4
-#define  PCIE_PHY_CMN_REG75_PLL_DONE	0x3
+#define IMX8MM_PCIE_PHY_CMN_REG075	0x1D4
+#define  ANA_PLL_DONE			0x3
 #define PCIE_PHY_TRSV_REG5		0x414
-#define  PCIE_PHY_TRSV_REG5_GEN1_DEEMP	0x2D
 #define PCIE_PHY_TRSV_REG6		0x418
-#define  PCIE_PHY_TRSV_REG6_GEN2_DEEMP	0xF

 #define IMX8MM_GPR_PCIE_REF_CLK_SEL	GENMASK(25, 24)
 #define IMX8MM_GPR_PCIE_REF_CLK_PLL

	FIELD_PREP(IMX8MM_GPR_PCIE_REF_CLK_SEL, 0x3)

quoted

@@ -47,16 +48,23 @@
 #define IMX8MM_GPR_PCIE_SSC_EN		BIT(16)
 #define IMX8MM_GPR_PCIE_AUX_EN_OVERRIDE	BIT(9)

+enum imx8_pcie_phy_type {
+	IMX8MM,
+	IMX8MP,
+};
+
 struct imx8_pcie_phy {
 	void __iomem		*base;
 	struct clk		*clk;
 	struct phy		*phy;
 	struct regmap		*iomuxc_gpr;
 	struct reset_control	*reset;
+	struct reset_control	*perst;
 	u32			refclk_pad_mode;
 	u32			tx_deemph_gen1;
 	u32			tx_deemph_gen2;
 	bool			clkreq_unused;
+	enum imx8_pcie_phy_type	variant;
 };

 static int imx8_pcie_phy_init(struct phy *phy) @@ -68,31 +76,20 @@

static int imx8_pcie_phy_init(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->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;
+	case IMX8MP:
+		reset_control_assert(imx8_phy->perst);
+		break;
+	}

 	if (pad_mode == IMX8_PCIE_REFCLK_PAD_INPUT ||
 	    pad_mode == IMX8_PCIE_REFCLK_PAD_UNUSED) { @@ -120,20

+117,44 @@

quoted

static int imx8_pcie_phy_init(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);
+
+	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);

-	reset_control_deassert(imx8_phy->reset);
+	switch (imx8_phy->variant) {
+	case IMX8MP:
+		reset_control_deassert(imx8_phy->perst);
+		fallthrough;
+	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_REG75,

quoted

-				 val, val == PCIE_PHY_CMN_REG75_PLL_DONE,
-				 10, 20000);
+	ret = readl_poll_timeout(imx8_phy->base +

IMX8MM_PCIE_PHY_CMN_REG075,

quoted

+				 val, val == ANA_PLL_DONE, 10, 20000);
 	return ret;
 }

@@ -160,6 +181,13 @@ static const struct phy_ops imx8_pcie_phy_ops = {
 	.owner		= THIS_MODULE,
 };

+static const struct of_device_id imx8_pcie_phy_of_match[] = {
+	{.compatible = "fsl,imx8mm-pcie-phy", .data = (void *)IMX8MM},
+	{.compatible = "fsl,imx8mp-pcie-phy", .data = (void *)IMX8MP},
+	{ },
+};
+MODULE_DEVICE_TABLE(of, imx8_pcie_phy_of_match);
+
 static int imx8_pcie_phy_probe(struct platform_device *pdev)  {
 	struct phy_provider *phy_provider;

@@ -172,6 +200,9 @@ static int imx8_pcie_phy_probe(struct

platform_device *pdev)

quoted

 	if (!imx8_phy)
 		return -ENOMEM;

+	imx8_phy->variant =
+		(enum imx8_pcie_phy_type)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);

@@ -196,8 +227,16 @@ static int imx8_pcie_phy_probe(struct

platform_device *pdev)

quoted

 	}

 	/* Grab GPR config register range */
-	imx8_phy->iomuxc_gpr =
-		 syscon_regmap_lookup_by_compatible("fsl,imx6q-iomuxc-gpr");
+	switch (imx8_phy->variant) {
+	case IMX8MM:
+		imx8_phy->iomuxc_gpr =
+

syscon_regmap_lookup_by_compatible("fsl,imx8mm-iomuxc-gpr");

quoted

+		break;
+	case IMX8MP:
+		imx8_phy->iomuxc_gpr =
+

syscon_regmap_lookup_by_compatible("fsl,imx8mp-iomuxc-gpr");

quoted

+		break;
+	}

Oh, I had a real phandle in DT in mind for this, but I see how this would be
hard to introduce in a backward compatible manner for the 8MM.
At least this way it is fully contained in the driver and doesn't leak into DT
compatibles.

Maybe we could make this a little nicer by just having an const array of iomux
syscon compatibles indexed by imx8_phy->variant, to avoid the switch and the
resulting code (almost-)duplication.

Hi Lucas:
Thanks for your comments.
Do you mean a drvdata struct indexed by variant, and contains the const array
of iomux syscon compatible like below?

+static const struct imx8_pcie_phy_drvdata drvdata[] = {
+       [IMX8MM] = {
+               .variant = IMX8MM,
+               .gpr = "fsl,imx8mm-iomuxc-gpr",
+       },
+
+       [IMX8MP] = {
+               .variant = IMX8MP,
+               .gpr = "fsl,imx8mp-iomuxc-gpr",
+       },
+};
+

Then, we can get the drvdata, and find the according gpr syscon regmap below.

+       imx8_phy->drvdata = of_device_get_match_data(dev);
...
+       imx8_phy->iomuxc_gpr =
+                syscon_regmap_lookup_by_compatible(imx8_phy->drvdata->gpr);

If yes, I would do the changes, and issue the v6 later.

Best Regards
Richard Zhu

Regards,
Lucas

quoted

 	if (IS_ERR(imx8_phy->iomuxc_gpr)) {
 		dev_err(dev, "unable to find iomuxc registers\n");
 		return PTR_ERR(imx8_phy->iomuxc_gpr); @@ -208,6 +247,14 @@

static

quoted

int imx8_pcie_phy_probe(struct platform_device *pdev)
 		dev_err(dev, "Failed to get PCIEPHY reset control\n");
 		return PTR_ERR(imx8_phy->reset);
 	}
+	if (imx8_phy->variant == IMX8MP) {
+		imx8_phy->perst =
+			devm_reset_control_get_exclusive(dev, "perst");
+		if (IS_ERR(imx8_phy->perst)) {
+			dev_err(dev, "Failed to get PCIE PHY PERST control\n");
+			return PTR_ERR(imx8_phy->perst);
+		}
+	}

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	imx8_phy->base = devm_ioremap_resource(dev, res); @@ -225,12 +272,6

@@ 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 = {