Re: [PATCH v4 4/5] phy: fsl-imx8mq-usb: add control register regmap

[Frank Li <Frank.li@nxp.com>]

On Fri, Jun 05, 2026 at 07:13:05PM +0800, Xu Yang wrote:
> From: Xu Yang <xu.yang_2@nxp.com>
>
> The CR port is a simple 16-bit data/address parallel port that is
> accessed through 32-bit MMIO registers for on-chip access to the
> control registers inside the USB 3.0 femtoPHY. Add control register
> regmap and export these registers by debugfs to help PHY's diagnostic.
>
> Signed-off-by: Xu Yang <xu.yang_2@nxp.com>
>

Reviewed-by: Frank Li <Frank.Li@nxp.com>

> ---
> Changes in v4:
>  - improve commit message as Haibo's suggestion
> Changes in v3:
>  - drop Frank's tag because it includes other changes
>  - new patch
> ---
>  drivers/phy/freescale/phy-fsl-imx8mq-usb.c | 27 ++++++++++++++++++++++++++-
>  1 file changed, 26 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/phy/freescale/phy-fsl-imx8mq-usb.c b/drivers/phy/freescale/phy-fsl-imx8mq-usb.c
> index 27aa696f5dd4..e24f46d7924b 100644
> --- a/drivers/phy/freescale/phy-fsl-imx8mq-usb.c
> +++ b/drivers/phy/freescale/phy-fsl-imx8mq-usb.c
> @@ -1,5 +1,5 @@
>  // SPDX-License-Identifier: GPL-2.0+
> -/* Copyright (c) 2017 NXP. */
> +/* Copyright 2017-2026 NXP. */
>
>  #include <linux/bitfield.h>
>  #include <linux/clk.h>
> @@ -11,6 +11,7 @@
>  #include <linux/platform_device.h>
>  #include <linux/pm_runtime.h>
>  #include <linux/regulator/consumer.h>
> +#include <linux/regmap.h>
>  #include <linux/usb/typec_mux.h>
>
>  #define PHY_CTRL0			0x0
> @@ -56,6 +57,8 @@
>  #define PHY_CTRL6_ALT_CLK_EN		BIT(1)
>  #define PHY_CTRL6_ALT_CLK_SEL		BIT(0)
>
> +#define PHY_CRCTL			0x30
> +
>  #define PHY_TUNE_DEFAULT		0xffffffff
>
>  #define TCA_CLK_RST			0x00
> @@ -119,6 +122,7 @@ struct imx8mq_usb_phy {
>  	void __iomem *base;
>  	struct regulator *vbus;
>  	struct tca_blk *tca;
> +	struct regmap *cr_regmap;
>  	u32 pcs_tx_swing_full;
>  	u32 pcs_tx_deemph_3p5db;
>  	u32 tx_vref_tune;
> @@ -667,6 +671,14 @@ static const struct of_device_id imx8mq_usb_phy_of_match[] = {
>  };
>  MODULE_DEVICE_TABLE(of, imx8mq_usb_phy_of_match);
>
> +static const struct regmap_config imx_cr_regmap_config = {
> +	.name = "cr",
> +	.reg_bits = 32,
> +	.val_bits = 32,
> +	.reg_stride = 4,
> +	.max_register = 0x7,
> +};
> +
>  static int imx8mq_usb_phy_probe(struct platform_device *pdev)
>  {
>  	struct phy_provider *phy_provider;
> @@ -696,6 +708,13 @@ static int imx8mq_usb_phy_probe(struct platform_device *pdev)
>  	if (IS_ERR(imx_phy->base))
>  		return PTR_ERR(imx_phy->base);
>
> +	imx_phy->cr_regmap = devm_regmap_init_mmio(dev, imx_phy->base + PHY_CRCTL,
> +						   &imx_cr_regmap_config);
> +	if (IS_ERR(imx_phy->cr_regmap)) {
> +		dev_warn(dev, "Fail to init debug register regmap\n");
> +		imx_phy->cr_regmap = NULL;
> +	}
> +
>  	ret = devm_pm_runtime_set_active_enabled(dev);
>  	if (ret)
>  		return dev_err_probe(dev, ret, "Failed to enable runtime PM\n");
> @@ -731,6 +750,9 @@ static int imx8mq_usb_phy_runtime_suspend(struct device *dev)
>  {
>  	struct imx8mq_usb_phy *imx_phy = dev_get_drvdata(dev);
>
> +	if (imx_phy->cr_regmap)
> +		regcache_cache_only(imx_phy->cr_regmap, true);
> +

I think this common problem, is possible to change
regmap_read_debugfs(), let it call runtime_pm_get(), there are already
have runtime_pm in regmap field.

So you debug fs always to get update value, instead cached value?

Frank

>  	clk_disable_unprepare(imx_phy->alt_clk);
>  	clk_disable_unprepare(imx_phy->clk);
>
> @@ -752,6 +774,9 @@ static int imx8mq_usb_phy_runtime_resume(struct device *dev)
>  		return ret;
>  	}
>
> +	if (imx_phy->cr_regmap)
> +		regcache_cache_only(imx_phy->cr_regmap, false);
> +
>  	return 0;
>  }
>
>
> --
> 2.34.1
>