Re: [PATCH v4 2/2] phy: intel: Add Keem Bay USB PHY support

[Andy Shevchenko]

On Mon, Nov 16, 2020 at 08:08:31PM +0800, Wan Ahmad Zainie wrote:
> Add PHY driver for the USB3.1 and USB 2.0 PHYs found on Intel
> Keem Bay SoC. This driver takes care of enabling the required
> USB susbsystem (USS) clocks, initializing the PHYs and turning
> on/off the USB dwc3 core.

FWIW,
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>

> Signed-off-by: Wan Ahmad Zainie <wan.ahmad.zainie.wan.mohamad@xxxxxxxxx>
> ---
>  drivers/phy/intel/Kconfig                 |  12 +
>  drivers/phy/intel/Makefile                |   1 +
>  drivers/phy/intel/phy-intel-keembay-usb.c | 301 ++++++++++++++++++++++
>  3 files changed, 314 insertions(+)
>  create mode 100644 drivers/phy/intel/phy-intel-keembay-usb.c
> 
> diff --git a/drivers/phy/intel/Kconfig b/drivers/phy/intel/Kconfig
> index 58ec695c92ec..f72c699a3e02 100644
> --- a/drivers/phy/intel/Kconfig
> +++ b/drivers/phy/intel/Kconfig
> @@ -14,6 +14,18 @@ config PHY_INTEL_KEEMBAY_EMMC
>  	  To compile this driver as a module, choose M here: the module
>  	  will be called phy-keembay-emmc.ko.
>  
> +config PHY_INTEL_KEEMBAY_USB
> +	tristate "Intel Keem Bay USB PHY driver"
> +	depends on ARCH_KEEMBAY || COMPILE_TEST
> +	depends on HAS_IOMEM
> +	select GENERIC_PHY
> +	select REGMAP_MMIO
> +	help
> +	  Choose this option if you have an Intel Keem Bay SoC.
> +
> +	  To compile this driver as a module, choose M here: the module
> +	  will be called phy-keembay-usb.ko.
> +
>  config PHY_INTEL_LGM_COMBO
>  	bool "Intel Lightning Mountain ComboPHY driver"
>  	depends on X86 || COMPILE_TEST
> diff --git a/drivers/phy/intel/Makefile b/drivers/phy/intel/Makefile
> index a5e0af5ccd75..14550981a707 100644
> --- a/drivers/phy/intel/Makefile
> +++ b/drivers/phy/intel/Makefile
> @@ -1,4 +1,5 @@
>  # SPDX-License-Identifier: GPL-2.0
>  obj-$(CONFIG_PHY_INTEL_KEEMBAY_EMMC)	+= phy-intel-keembay-emmc.o
> +obj-$(CONFIG_PHY_INTEL_KEEMBAY_USB)	+= phy-intel-keembay-usb.o
>  obj-$(CONFIG_PHY_INTEL_LGM_COMBO)	+= phy-intel-lgm-combo.o
>  obj-$(CONFIG_PHY_INTEL_LGM_EMMC)	+= phy-intel-lgm-emmc.o
> diff --git a/drivers/phy/intel/phy-intel-keembay-usb.c b/drivers/phy/intel/phy-intel-keembay-usb.c
> new file mode 100644
> index 000000000000..c8b05f7b2445
> --- /dev/null
> +++ b/drivers/phy/intel/phy-intel-keembay-usb.c
> @@ -0,0 +1,301 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Intel Keem Bay USB PHY driver
> + * Copyright (C) 2020 Intel Corporation
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/bits.h>
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/module.h>
> +#include <linux/phy/phy.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +
> +/* USS (USB Subsystem) clock control registers */
> +#define USS_CPR_CLK_EN		0x00
> +#define USS_CPR_CLK_SET		0x04
> +#define USS_CPR_CLK_CLR		0x08
> +#define USS_CPR_RST_EN		0x10
> +#define USS_CPR_RST_SET		0x14
> +#define USS_CPR_RST_CLR		0x18
> +
> +/* USS clock/reset bit fields */
> +#define USS_CPR_PHY_TST		BIT(6)
> +#define USS_CPR_LOW_JIT		BIT(5)
> +#define USS_CPR_CORE		BIT(4)
> +#define USS_CPR_SUSPEND		BIT(3)
> +#define USS_CPR_ALT_REF		BIT(2)
> +#define USS_CPR_REF		BIT(1)
> +#define USS_CPR_SYS		BIT(0)
> +#define USS_CPR_MASK		GENMASK(6, 0)
> +
> +/* USS APB slave registers */
> +#define USS_USB_CTRL_CFG0		0x10
> +#define  VCC_RESET_N_MASK		BIT(31)
> +
> +#define USS_USB_PHY_CFG0		0x30
> +#define  POR_MASK			BIT(15)
> +#define  PHY_RESET_MASK			BIT(14)
> +#define  PHY_REF_USE_PAD_MASK		BIT(5)
> +
> +#define USS_USB_PHY_CFG6		0x64
> +#define  PHY0_SRAM_EXT_LD_DONE_MASK	BIT(23)
> +
> +#define USS_USB_PARALLEL_IF_CTRL	0xa0
> +#define  USB_PHY_CR_PARA_SEL_MASK	BIT(2)
> +
> +#define USS_USB_TSET_SIGNALS_AND_GLOB	0xac
> +#define  USB_PHY_CR_PARA_CLK_EN_MASK	BIT(7)
> +
> +#define USS_USB_STATUS_REG		0xb8
> +#define  PHY0_SRAM_INIT_DONE_MASK	BIT(3)
> +
> +#define USS_USB_TIEOFFS_CONSTANTS_REG1	0xc0
> +#define  IDDQ_ENABLE_MASK		BIT(10)
> +
> +struct keembay_usb_phy {
> +	struct device *dev;
> +	struct regmap *regmap_cpr;
> +	struct regmap *regmap_slv;
> +};
> +
> +static const struct regmap_config keembay_regmap_config = {
> +	.reg_bits = 32,
> +	.val_bits = 32,
> +	.reg_stride = 4,
> +	.max_register = USS_USB_TIEOFFS_CONSTANTS_REG1,
> +};
> +
> +static int keembay_usb_clocks_on(struct keembay_usb_phy *priv)
> +{
> +	int ret;
> +
> +	ret = regmap_update_bits(priv->regmap_cpr, USS_CPR_CLK_SET,
> +				 USS_CPR_MASK, USS_CPR_MASK);
> +	if (ret) {
> +		dev_err(priv->dev, "error clock set: %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = regmap_update_bits(priv->regmap_cpr, USS_CPR_RST_SET,
> +				 USS_CPR_MASK, USS_CPR_MASK);
> +	if (ret) {
> +		dev_err(priv->dev, "error reset set: %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = regmap_update_bits(priv->regmap_slv,
> +				 USS_USB_TIEOFFS_CONSTANTS_REG1,
> +				 IDDQ_ENABLE_MASK,
> +				 FIELD_PREP(IDDQ_ENABLE_MASK, 0));
> +	if (ret) {
> +		dev_err(priv->dev, "error iddq disable: %d\n", ret);
> +		return ret;
> +	}
> +
> +	/* Wait 30us to ensure all analog blocks are powered up. */
> +	usleep_range(30, 60);
> +
> +	ret = regmap_update_bits(priv->regmap_slv, USS_USB_PHY_CFG0,
> +				 PHY_REF_USE_PAD_MASK,
> +				 FIELD_PREP(PHY_REF_USE_PAD_MASK, 1));
> +	if (ret)
> +		dev_err(priv->dev, "error ref clock select: %d\n", ret);
> +
> +	return ret;
> +}
> +
> +static int keembay_usb_core_off(struct keembay_usb_phy *priv)
> +{
> +	int ret;
> +
> +	ret = regmap_update_bits(priv->regmap_slv, USS_USB_CTRL_CFG0,
> +				 VCC_RESET_N_MASK,
> +				 FIELD_PREP(VCC_RESET_N_MASK, 0));
> +	if (ret)
> +		dev_err(priv->dev, "error core reset: %d\n", ret);
> +
> +	return ret;
> +}
> +
> +static int keembay_usb_core_on(struct keembay_usb_phy *priv)
> +{
> +	int ret;
> +
> +	ret = regmap_update_bits(priv->regmap_slv, USS_USB_CTRL_CFG0,
> +				 VCC_RESET_N_MASK,
> +				 FIELD_PREP(VCC_RESET_N_MASK, 1));
> +	if (ret)
> +		dev_err(priv->dev, "error core on: %d\n", ret);
> +
> +	return ret;
> +}
> +
> +static int keembay_usb_phys_on(struct keembay_usb_phy *priv)
> +{
> +	int ret;
> +
> +	ret = regmap_update_bits(priv->regmap_slv, USS_USB_PHY_CFG0,
> +				 POR_MASK | PHY_RESET_MASK,
> +				 FIELD_PREP(POR_MASK | PHY_RESET_MASK, 0));
> +	if (ret)
> +		dev_err(priv->dev, "error phys on: %d\n", ret);
> +
> +	return ret;
> +}
> +
> +static int keembay_usb_phy_init(struct phy *phy)
> +{
> +	struct keembay_usb_phy *priv = phy_get_drvdata(phy);
> +	u32 val;
> +	int ret;
> +
> +	ret = keembay_usb_core_off(priv);
> +	if (ret)
> +		return ret;
> +
> +	/*
> +	 * According to Keem Bay datasheet, wait minimum 20us after clock
> +	 * enable before bringing PHYs out of reset.
> +	 */
> +	usleep_range(20, 40);
> +
> +	ret = keembay_usb_phys_on(priv);
> +	if (ret)
> +		return ret;
> +
> +	ret = regmap_update_bits(priv->regmap_slv,
> +				 USS_USB_TSET_SIGNALS_AND_GLOB,
> +				 USB_PHY_CR_PARA_CLK_EN_MASK,
> +				 FIELD_PREP(USB_PHY_CR_PARA_CLK_EN_MASK, 0));
> +	if (ret) {
> +		dev_err(priv->dev, "error cr clock disable: %d\n", ret);
> +		return ret;
> +	}
> +
> +	/*
> +	 * According to Keem Bay datasheet, wait 2us after disabling the
> +	 * clock into the USB 3.x parallel interface.
> +	 */
> +	udelay(2);
> +
> +	ret = regmap_update_bits(priv->regmap_slv,
> +				 USS_USB_PARALLEL_IF_CTRL,
> +				 USB_PHY_CR_PARA_SEL_MASK,
> +				 FIELD_PREP(USB_PHY_CR_PARA_SEL_MASK, 1));
> +	if (ret) {
> +		dev_err(priv->dev, "error cr select: %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = regmap_update_bits(priv->regmap_slv,
> +				 USS_USB_TSET_SIGNALS_AND_GLOB,
> +				 USB_PHY_CR_PARA_CLK_EN_MASK,
> +				 FIELD_PREP(USB_PHY_CR_PARA_CLK_EN_MASK, 1));
> +	if (ret) {
> +		dev_err(priv->dev, "error cr clock enable: %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = regmap_read_poll_timeout(priv->regmap_slv, USS_USB_STATUS_REG,
> +				       val, val & PHY0_SRAM_INIT_DONE_MASK,
> +				       USEC_PER_MSEC, 10 * USEC_PER_MSEC);
> +	if (ret) {
> +		dev_err(priv->dev, "SRAM init not done: %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = regmap_update_bits(priv->regmap_slv, USS_USB_PHY_CFG6,
> +				 PHY0_SRAM_EXT_LD_DONE_MASK,
> +				 FIELD_PREP(PHY0_SRAM_EXT_LD_DONE_MASK, 1));
> +	if (ret) {
> +		dev_err(priv->dev, "error SRAM init done set: %d\n", ret);
> +		return ret;
> +	}
> +
> +	/*
> +	 * According to Keem Bay datasheet, wait 20us after setting the
> +	 * SRAM load done bit, before releasing the controller reset.
> +	 */
> +	usleep_range(20, 40);
> +
> +	return keembay_usb_core_on(priv);
> +}
> +
> +static const struct phy_ops ops = {
> +	.init		= keembay_usb_phy_init,
> +	.owner		= THIS_MODULE,
> +};
> +
> +static int keembay_usb_phy_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct keembay_usb_phy *priv;
> +	struct phy *generic_phy;
> +	struct phy_provider *phy_provider;
> +	void __iomem *base;
> +	int ret;
> +
> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	base = devm_platform_ioremap_resource_byname(pdev, "cpr-apb-base");
> +	if (IS_ERR(base))
> +		return PTR_ERR(base);
> +
> +	priv->regmap_cpr = devm_regmap_init_mmio(dev, base,
> +						 &keembay_regmap_config);
> +	if (IS_ERR(priv->regmap_cpr))
> +		return PTR_ERR(priv->regmap_cpr);
> +
> +	base = devm_platform_ioremap_resource_byname(pdev, "slv-apb-base");
> +	if (IS_ERR(base))
> +		return PTR_ERR(base);
> +
> +	priv->regmap_slv = devm_regmap_init_mmio(dev, base,
> +						 &keembay_regmap_config);
> +	if (IS_ERR(priv->regmap_slv))
> +		return PTR_ERR(priv->regmap_slv);
> +
> +	generic_phy = devm_phy_create(dev, dev->of_node, &ops);
> +	if (IS_ERR(generic_phy))
> +		return dev_err_probe(dev, PTR_ERR(generic_phy),
> +				     "failed to create PHY\n");
> +
> +	phy_set_drvdata(generic_phy, priv);
> +	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
> +	if (IS_ERR(phy_provider))
> +		return dev_err_probe(dev, PTR_ERR(phy_provider),
> +				     "failed to register phy provider\n");
> +
> +	/* Setup USB subsystem clocks */
> +	ret = keembay_usb_clocks_on(priv);
> +	if (ret)
> +		return ret;
> +
> +	/* and turn on the DWC3 core, prior to DWC3 driver init. */
> +	return keembay_usb_core_on(priv);
> +}
> +
> +static const struct of_device_id keembay_usb_phy_dt_ids[] = {
> +	{ .compatible = "intel,keembay-usb-phy" },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, keembay_usb_phy_dt_ids);
> +
> +static struct platform_driver keembay_usb_phy_driver = {
> +	.probe		= keembay_usb_phy_probe,
> +	.driver		= {
> +		.name	= "keembay-usb-phy",
> +		.of_match_table = keembay_usb_phy_dt_ids,
> +	},
> +};
> +module_platform_driver(keembay_usb_phy_driver);
> +
> +MODULE_AUTHOR("Wan Ahmad Zainie <wan.ahmad.zainie.wan.mohamad@xxxxxxxxx>");
> +MODULE_DESCRIPTION("Intel Keem Bay USB PHY driver");
> +MODULE_LICENSE("GPL v2");
> -- 
> 2.17.1
> 

-- 
With Best Regards,
Andy Shevchenko