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

[Richard Zhu <hongxing.zhu@nxp.com>]

> -----Original Message-----
> From: Tim Harvey <tharvey@gateworks.com>
> Sent: Friday, October 22, 2021 12:00 AM
> To: Richard Zhu <hongxing.zhu@nxp.com>
> Cc: Lucas Stach <l.stach@pengutronix.de>; Kishon Vijay Abraham I
> <kishon@ti.com>; vkoul@kernel.org; Rob Herring <robh@kernel.org>;
> galak@kernel.crashing.org; Shawn Guo <shawnguo@kernel.org>;
> linux-phy@lists.infradead.org; Device Tree Mailing List
> <devicetree@vger.kernel.org>; Linux ARM Mailing List
> <linux-arm-kernel@lists.infradead.org>; open list
> <linux-kernel@vger.kernel.org>; Sascha Hauer <kernel@pengutronix.de>;
> dl-linux-imx <linux-imx@nxp.com>
> Subject: Re: [PATCH v3 5/9] phy: freescale: pcie: initialize the imx8 pcie
> standalone phy driver
> 
> On Tue, Oct 12, 2021 at 2:06 AM Richard Zhu <hongxing.zhu@nxp.com>
> wrote:
> >
> > 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@nxp.com>
> > ---
> >  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
> > +       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;
> > +       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 ?
> 
> Hi Richard,
> 
> use the enumerated type for the comparison above for clarity:
> imx8_phy->refclk_pad_mode == IMX8_PCIE_REFCLK_PAD_INPUT
> 
> Also, this is the configuration that makes my imx8mm-venice boards which do
> not use CLKREQ# hang while waiting for PHY. I am setting in my dt:
> &pcie_phy {
>         fsl,refclk-pad-mode = <IMX8_PCIE_REFCLK_PAD_INPUT>;
>         clocks = <&clk IMX8MM_CLK_DUMMY>;
>         status = "okay";
> };
> 
> The NXP kernel woudl always set this bit to 0 which makes my board work.
> 
> The IMX8MMRM documentation appears incorrect here:
> IOMUXC_GPR_GPR14 bit 9: GPR_PCIE1_ PHY_I_AUX_ EN_OVERRIDE_ EN:
> {GPR_PCIE1_PHY_I_AUX_EN_OVERRIDE_EN,
> GPR_PCIE1_PHY_FUNC_I_AUX_EN}
>  2'b00 External Reference Clock I/O (for PLL) Disable
>  2'b01 External Reference Clock I/O (for PLL) Enable
>  2'b10 External Reference Clock I/O (for PLL) Disable
>  2'b11 External Reference Clock I/O (for PLL) output is controlled by CLKREQ#
> 
> How is it they define this as a single bit then give descriptions for
> 2 bits? Something is wrong here.
> 
[Richard Zhu] The descriptions are not correct, please ignore them.

> > +                          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 ?
> 
> imx8_phy->refclk_pad_mode == IMX8_PCIE_REFCLK_PAD_INPUT
[Richard Zhu] Got that. Thanks.

BR
Richard
> 
> Best regards,
> 
> Tim
> 
> > +                          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);
> > +
> > +       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");
> > +       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");
> > --
> > 2.25.1
> >