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    SubjectRe: [PATCH v4 5/8] phy: freescale: pcie: Initialize the imx8 pcie standalone phy driver
    On Mon, Nov 1, 2021 at 1:19 AM Richard Zhu <hongxing.zhu@nxp.com> wrote:
    >
    > > -----Original Message-----
    > > From: Tim Harvey <tharvey@gateworks.com>
    > > Sent: Saturday, October 30, 2021 1:45 AM
    > > To: Richard Zhu <hongxing.zhu@nxp.com>; Marcel Ziswiler
    > > <marcel.ziswiler@toradex.com>
    > > Cc: kishon@ti.com; vkoul@kernel.org; robh@kernel.org;
    > > l.stach@pengutronix.de; shawnguo@kernel.org;
    > > galak@kernel.crashing.org; linux-phy@lists.infradead.org;
    > > linux-arm-kernel@lists.infradead.org; kernel@pengutronix.de;
    > > devicetree@vger.kernel.org; linux-kernel@vger.kernel.org; dl-linux-imx
    > > <linux-imx@nxp.com>
    > > Subject: Re: [PATCH v4 5/8] phy: freescale: pcie: Initialize the imx8 pcie
    > > standalone phy driver
    > >
    > > On Fri, Oct 29, 2021 at 1:45 AM Richard Zhu <hongxing.zhu@nxp.com>
    > > wrote:
    > > >
    > > >
    > > > > -----Original Message-----
    > > > > From: Marcel Ziswiler <marcel.ziswiler@toradex.com>
    > > > > Sent: Friday, October 29, 2021 4:13 PM
    > > > > To: kishon@ti.com; vkoul@kernel.org; robh@kernel.org;
    > > > > l.stach@pengutronix.de; shawnguo@kernel.org;
    > > tharvey@gateworks.com;
    > > > > galak@kernel.crashing.org; Richard Zhu <hongxing.zhu@nxp.com>
    > > > > Cc: linux-phy@lists.infradead.org;
    > > > > linux-arm-kernel@lists.infradead.org;
    > > > > kernel@pengutronix.de; devicetree@vger.kernel.org;
    > > > > linux-kernel@vger.kernel.org; dl-linux-imx <linux-imx@nxp.com>
    > > > > Subject: Re: [PATCH v4 5/8] phy: freescale: pcie: Initialize the
    > > > > imx8 pcie standalone phy driver
    > > > >
    > > > > On Thu, 2021-10-28 at 15:27 +0800, Richard Zhu wrote:
    > > > > > Add the standalone i.MX8 PCIe PHY driver.
    > > > > >
    > > > > > Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
    > > > > > Tested-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
    > > > >
    > > > > Unfortunately, this version no longer works for our
    > > > > IMX8_PCIE_REFCLK_PAD_OUTPUT use-case. Further comments in-
    > > lined
    > > > > below.
    > > > >
    > > > [Richard Zhu] Sorry to hear about that. Then, it seems that this bit
    > > > should be set anyway.
    > > > It's hard to understand this bit refer to the RM document. Sigh ☹.
    > > > Would set the AUX_EN bit later.
    > > >
    > > > > > ---
    > > > > > drivers/phy/freescale/Kconfig | 9 +
    > > > > > drivers/phy/freescale/Makefile | 1 +
    > > > > > drivers/phy/freescale/phy-fsl-imx8m-pcie.c | 234
    > > > > > +++++++++++++++++++++
    > > > > > 3 files changed, 244 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..de9ee7020f76
    > > > > > 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"
    > > > >
    > > > > Above description is missing the M as in i.MX 8M.
    > > > [Richard Zhu] Okay, would be added later.
    > > > Thanks.
    > > >
    > > > >
    > > > > > + depends on OF && HAS_IOMEM
    > > > > > + select GENERIC_PHY
    > > > > > + default ARCH_MXC && ARM64
    > > > > > + 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..4b4402eaddcc
    > > > > > --- /dev/null
    > > > > > +++ b/drivers/phy/freescale/phy-fsl-imx8m-pcie.c
    > > > > > @@ -0,0 +1,234 @@
    > > > > > +// 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_AUX_EN_OVERRIDE BIT(9)
    > > > > > +
    > > > > > +struct imx8_pcie_phy {
    > > > > > + void __iomem *base;
    > > > > > + struct clk *clk;
    > > > > > + struct phy *phy;
    > > > > > + struct regmap *iomuxc_gpr;
    > > > > > + struct reset_control *reset;
    > > > > > + u32 refclk_pad_mode;
    > > > > > + u32 tx_deemph_gen1;
    > > > > > + u32 tx_deemph_gen2;
    > > > > > + bool clkreq_unused; };
    > > > > > +
    > > > > > +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);
    > > > > > +
    > > > > > + 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,
    > > > > > + pad_mode ==
    > > > > IMX8_PCIE_REFCLK_PAD_INPUT ?
    > > > > > + IMX8MM_GPR_PCIE_AUX_EN :
    > > > > 0);
    > > > >
    > > > > V3 had IMX8MM_GPR_PCIE_AUX_EN always enabled. Turns out V4
    > > stopped
    > > > > working for our output use-case as it only enables it for the input
    > > > > use-case. If I enable this one always it starts working again.
    > > > [Richard Zhu] See my comment above.
    > > > Sorry to bring the regression on your board.
    > > >
    > >
    > > Marcel,
    > >
    > > Your board does not use an external clk, but does it hook up CLKREQ#
    > > from the socket to either I2C4_SCL or UART4_RXD and pin muxed as
    > > such?
    > >
    > > For my board that uses an external clk and does not connect CLKREQ# to
    > > the IMX8MM I need to disable that bit. As Richard says we have invalid
    > > documentation for these bits unfortunately which is not helping.
    > >
    > > Richard, when we do figure out proper documentation for these bits I
    > > suggest you also add a comment block right above their #defines in the
    > > phy driver with the correct documentation to avoid future confusion.
    > > NXP has had so many mistakes in the various IMX8M RM's and I fear they
    > > will never get fixed.
    > [Richard Zhu] Hi Tim:
    > I took look at the validation codes, and found that the AUX_EN is always
    > set to be 1b'1. Whatever the reference clock mode is selected.
    > I'm sending a query email to design team, but I'm not sure I can get response
    > in time.
    > Can you help to take a double tests at your board when AUX_EN(bit19 of GPR14)
    > is set to be 1b'1 firstly?
    > Thanks in advanced.
    >

    Richard and Marcel,

    I apologize, my mistake I was referring to GPR14 bit 9 and not bit19
    in my testing above.

    I tested leaving bit 9 set and this still works on my boards with ext
    clk and no CLKREQ# as well as imx8mm-evk with ext clk and CLKREQ#.

    So the change on top of your v4 would be:

    diff --git a/drivers/phy/freescale/phy-fsl-imx8m-pcie.c
    b/drivers/phy/freescale/phy-fsl-imx8m-pcie.c
    index 4b4402eaddcc..003f575b36f0 100644
    --- a/drivers/phy/freescale/phy-fsl-imx8m-pcie.c
    +++ b/drivers/phy/freescale/phy-fsl-imx8m-pcie.c
    @@ -73,8 +73,7 @@ static int imx8_pcie_phy_init(struct phy *phy)
    0 : IMX8MM_GPR_PCIE_AUX_EN_OVERRIDE);
    regmap_update_bits(imx8_phy->iomuxc_gpr, IOMUXC_GPR14,
    IMX8MM_GPR_PCIE_AUX_EN,
    - pad_mode == IMX8_PCIE_REFCLK_PAD_INPUT ?
    - IMX8MM_GPR_PCIE_AUX_EN : 0);
    + 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,
    Marcel, does this look right for your board?

    Best regards,

    Tim

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