Re: [PATCH v3 5/9] phy: freescale: pcie: initialize the imx8 pcie standalone phy driver

From: Lucas Stach
Date: Fri Oct 15 2021 - 14:56:10 EST

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In reply to: Richard Zhu: "[PATCH v3 5/9] phy: freescale: pcie: initialize the imx8 pcie standalone phy driver"
Next in thread: Richard Zhu: "[PATCH v3 6/9] dt-bindings: imx6q-pcie: Add PHY phandles and name properties"
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Am Dienstag, dem 12.10.2021 um 16:41 +0800 schrieb Richard Zhu:
> Add the standalone i.MX8 PCIe PHY driver.
> Some reset bits should be manipulated between PHY configurations and
> status check(internal PLL is locked or not).
> So, do the PHY configuration in the phy_calibrate().
> And check the PHY is ready or not in the phy_init().
>
> Signed-off-by: Richard Zhu <hongxing.zhu@xxxxxxx>
> ---
> drivers/phy/freescale/Kconfig | 9 +
> drivers/phy/freescale/Makefile | 1 +
> drivers/phy/freescale/phy-fsl-imx8m-pcie.c | 218 +++++++++++++++++++++
> 3 files changed, 228 insertions(+)
> create mode 100644 drivers/phy/freescale/phy-fsl-imx8m-pcie.c
>
> diff --git a/drivers/phy/freescale/Kconfig b/drivers/phy/freescale/Kconfig
> index 320630ffe3cd..fb08e5242602 100644
> --- a/drivers/phy/freescale/Kconfig
> +++ b/drivers/phy/freescale/Kconfig
> @@ -14,3 +14,12 @@ config PHY_MIXEL_MIPI_DPHY
> help
> Enable this to add support for the Mixel DSI PHY as found
> on NXP's i.MX8 family of SOCs.
> +
> +config PHY_FSL_IMX8M_PCIE
> + tristate "Freescale i.MX8 PCIE PHY"
> + depends on OF && HAS_IOMEM
> + select GENERIC_PHY
> + default ARCH_MXC

Not sure if we need this default, but if you want to keep it add at
least a "&& ARM64" to not enable it on old 32bit i.MX SoCs.

> + help
> + Enable this to add support for the PCIE PHY as found on
> + i.MX8M family of SOCs.
> diff --git a/drivers/phy/freescale/Makefile b/drivers/phy/freescale/Makefile
> index 1d02e3869b45..55d07c742ab0 100644
> --- a/drivers/phy/freescale/Makefile
> +++ b/drivers/phy/freescale/Makefile
> @@ -1,3 +1,4 @@
> # SPDX-License-Identifier: GPL-2.0-only
> obj-$(CONFIG_PHY_FSL_IMX8MQ_USB) += phy-fsl-imx8mq-usb.o
> obj-$(CONFIG_PHY_MIXEL_MIPI_DPHY) += phy-fsl-imx8-mipi-dphy.o
> +obj-$(CONFIG_PHY_FSL_IMX8M_PCIE) += phy-fsl-imx8m-pcie.o
> diff --git a/drivers/phy/freescale/phy-fsl-imx8m-pcie.c b/drivers/phy/freescale/phy-fsl-imx8m-pcie.c
> new file mode 100644
> index 000000000000..317cf61bff37
> --- /dev/null
> +++ b/drivers/phy/freescale/phy-fsl-imx8m-pcie.c
> @@ -0,0 +1,218 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright 2021 NXP
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/io.h>
> +#include <linux/iopoll.h>
> +#include <linux/delay.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/mfd/syscon/imx7-iomuxc-gpr.h>
> +#include <linux/module.h>
> +#include <linux/phy/phy.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/reset.h>
> +#include <dt-bindings/phy/phy-imx8-pcie.h>
> +
> +#define IMX8MM_PCIE_PHY_CMN_REG061 0x184
> +#define ANA_PLL_CLK_OUT_TO_EXT_IO_EN BIT(0)
> +#define IMX8MM_PCIE_PHY_CMN_REG062 0x188
> +#define ANA_PLL_CLK_OUT_TO_EXT_IO_SEL BIT(3)
> +#define IMX8MM_PCIE_PHY_CMN_REG063 0x18C
> +#define AUX_PLL_REFCLK_SEL_SYS_PLL GENMASK(7, 6)
> +#define IMX8MM_PCIE_PHY_CMN_REG064 0x190
> +#define ANA_AUX_RX_TX_SEL_TX BIT(7)
> +#define ANA_AUX_RX_TERM_GND_EN BIT(3)
> +#define ANA_AUX_TX_TERM BIT(2)
> +#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 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)
> +#define IMX8MM_GPR_PCIE_REF_CLK_EXT FIELD_PREP(IMX8MM_GPR_PCIE_REF_CLK_SEL, 0x2)
> +#define IMX8MM_GPR_PCIE_AUX_EN BIT(19)
> +#define IMX8MM_GPR_PCIE_CMN_RST BIT(18)
> +#define IMX8MM_GPR_PCIE_POWER_OFF BIT(17)
> +#define IMX8MM_GPR_PCIE_SSC_EN BIT(16)
> +#define IMX8MM_GPR_PCIE_REF_USE_PAD BIT(9)
> +
> +struct imx8_pcie_phy {
> + u32 refclk_pad_mode;

Moving this to the end of the structure will get rid of a hole due to
padding.

> + void __iomem *base;
> + struct clk *clk;
> + struct phy *phy;
> + struct regmap *iomuxc_gpr;
> + struct reset_control *reset;
> +};
> +
> +static int imx8_pcie_phy_init(struct phy *phy)
> +{
> + int ret;
> + u32 val, pad_mode;
> + struct imx8_pcie_phy *imx8_phy = phy_get_drvdata(phy);
> +
> + reset_control_assert(imx8_phy->reset);
> +
> + regmap_update_bits(imx8_phy->iomuxc_gpr, IOMUXC_GPR14,
> + IMX8MM_GPR_PCIE_REF_USE_PAD,
> + imx8_phy->refclk_pad_mode == 1 ?
> + IMX8MM_GPR_PCIE_REF_USE_PAD : 0);
> + 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,
> + imx8_phy->refclk_pad_mode == 1 ?
> + 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);
> +
> +
> + pad_mode = imx8_phy->refclk_pad_mode;
> + if (pad_mode == IMX8_PCIE_REFCLK_PAD_INPUT) {
> + /* Configure the pad as input */
> + val = readl(imx8_phy->base + IMX8MM_PCIE_PHY_CMN_REG061);
> + writel(val & ~ANA_PLL_CLK_OUT_TO_EXT_IO_EN,
> + imx8_phy->base + IMX8MM_PCIE_PHY_CMN_REG061);
> + } else if (pad_mode == IMX8_PCIE_REFCLK_PAD_OUTPUT) {
> + /* Configure the PHY to output the refclock via pad */
> + writel(ANA_PLL_CLK_OUT_TO_EXT_IO_EN,
> + imx8_phy->base + IMX8MM_PCIE_PHY_CMN_REG061);
> + writel(ANA_PLL_CLK_OUT_TO_EXT_IO_SEL,
> + imx8_phy->base + IMX8MM_PCIE_PHY_CMN_REG062);
> + writel(AUX_PLL_REFCLK_SEL_SYS_PLL,
> + imx8_phy->base + IMX8MM_PCIE_PHY_CMN_REG063);
> + val = ANA_AUX_RX_TX_SEL_TX | ANA_AUX_TX_TERM;
> + writel(val | ANA_AUX_RX_TERM_GND_EN,
> + imx8_phy->base + IMX8MM_PCIE_PHY_CMN_REG064);
> + writel(ANA_AUX_RX_TERM | ANA_AUX_TX_LVL,
> + imx8_phy->base + IMX8MM_PCIE_PHY_CMN_REG065);
> + }
> +
> + /* Tune PHY de-emphasis setting to pass PCIe compliance. */
> + writel(PCIE_PHY_TRSV_REG5_GEN1_DEEMP,
> + imx8_phy->base + PCIE_PHY_TRSV_REG5);
> + writel(PCIE_PHY_TRSV_REG6_GEN2_DEEMP,
> + imx8_phy->base + PCIE_PHY_TRSV_REG6);

I guess those are at least in part board specific. Maybe it would be a
good idea to add DT properties to allow each board to specify the
actual de-emphasis values?

> +
> + reset_control_deassert(imx8_phy->reset);
> +
> + /* Polling to check the phy is ready or not. */
> + ret = readl_poll_timeout(imx8_phy->base + IMX8MM_PCIE_PHY_CMN_REG75,
> + val, val == PCIE_PHY_CMN_REG75_PLL_DONE,
> + 10, 20000);
> + return ret;
> +}
> +
> +static int imx8_pcie_phy_power_on(struct phy *phy)
> +{
> + struct imx8_pcie_phy *imx8_phy = phy_get_drvdata(phy);
> +
> + return clk_prepare_enable(imx8_phy->clk);
> +}
> +
> +static int imx8_pcie_phy_power_off(struct phy *phy)
> +{
> + struct imx8_pcie_phy *imx8_phy = phy_get_drvdata(phy);
> +
> + clk_disable_unprepare(imx8_phy->clk);
> +
> + return 0;
> +}
> +
> +static const struct phy_ops imx8_pcie_phy_ops = {
> + .init = imx8_pcie_phy_init,
> + .power_on = imx8_pcie_phy_power_on,
> + .power_off = imx8_pcie_phy_power_off,
> + .owner = THIS_MODULE,
> +};
> +
> +static int imx8_pcie_phy_probe(struct platform_device *pdev)
> +{
> + struct phy_provider *phy_provider;
> + struct device *dev = &pdev->dev;
> + struct device_node *np = dev->of_node;
> + struct imx8_pcie_phy *imx8_phy;
> + struct resource *res;
> +
> + imx8_phy = devm_kzalloc(dev, sizeof(*imx8_phy), GFP_KERNEL);
> + if (!imx8_phy)
> + return -ENOMEM;
> +
> + /* get PHY refclk pad mode */
> + of_property_read_u32(np, "fsl,refclk-pad-mode",
> + &imx8_phy->refclk_pad_mode);
> +
> + imx8_phy->clk = devm_clk_get(dev, "phy");
> + if (IS_ERR(imx8_phy->clk)) {
> + dev_err(dev, "failed to get imx pcie phy clock\n");
> + return PTR_ERR(imx8_phy->clk);
> + }
> +
> + /* Grab GPR config register range */
> + imx8_phy->iomuxc_gpr =
> + syscon_regmap_lookup_by_compatible("fsl,imx6q-iomuxc-gpr");

I would prefer if we could get the syscon via a phandle and make the
GPR register to use another cell of the handle.

That's not really important for the 8MM, where there is only one PCIe
PHY, but if we want to retrofit this model to the i.MX8MQ, we need to
deal with different GPR offsets for both PHYs and I would like to have
this explicit in the DT. Doing the same here would be good for
consistency.

Overall, looks much better than the last submission.

Regards,
Lucas

> + if (IS_ERR(imx8_phy->iomuxc_gpr)) {
> + dev_err(dev, "unable to find iomuxc registers\n");
> + return PTR_ERR(imx8_phy->iomuxc_gpr);
> + }
> +
> + imx8_phy->reset = devm_reset_control_get_exclusive(dev, "pciephy");
> + if (IS_ERR(imx8_phy->reset)) {
> + dev_err(dev, "Failed to get PCIEPHY reset control\n");
> + return PTR_ERR(imx8_phy->reset);
> + }
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + imx8_phy->base = devm_ioremap_resource(dev, res);
> + if (IS_ERR(imx8_phy->base))
> + return PTR_ERR(imx8_phy->base);
> +
> + imx8_phy->phy = devm_phy_create(dev, NULL, &imx8_pcie_phy_ops);
> + if (IS_ERR(imx8_phy->phy))
> + return PTR_ERR(imx8_phy->phy);
> +
> + phy_set_drvdata(imx8_phy->phy, imx8_phy);
> +
> + phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
> +
> + 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 = {
> + .name = "imx8-pcie-phy",
> + .of_match_table = imx8_pcie_phy_of_match,
> + }
> +};
> +module_platform_driver(imx8_pcie_phy_driver);
> +
> +MODULE_DESCRIPTION("FSL IMX8 PCIE PHY driver");
> +MODULE_LICENSE("GPL");

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In reply to: Richard Zhu: "[PATCH v3 5/9] phy: freescale: pcie: initialize the imx8 pcie standalone phy driver"
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