Subject: Re: [PATCH v2 8/8] usb: dwc3: Add Amlogic G12A DWC3 glue

From: Chunfeng Yun <[email-masked]>
Date: Thu, 7 Mar 2019 10:02:56 +0800

Hi,
On Mon, 2019-03-04 at 11:38 +0100, Neil Armstrong wrote:
> Adds support for Amlogic G12A USB Control Glue HW.
> 
> The Amlogic G12A SoC Family embeds 2 USB Controllers :
> - a DWC3 IP configured as Host for USB2 and USB3
> - a DWC2 IP configured as Peripheral USB2 Only
> 
> A glue connects these both controllers to 2 USB2 PHYs, and optionnally
> to an USB3+PCIE Combo PHY shared with the PCIE controller.
> 
> The Glue configures the UTMI 8bit interfaces for the USB2 PHYs, including
> routing of the OTG PHY between the DWC3 and DWC2 controllers, and
> setups the on-chip OTG mode selection for this PHY.
> 
> This drivers supports the on-probe setup of the OTG mode, and manually
> via a debugfs interface. The IRQ mode change detect is yet to be added
> in a future patchset, mainly due to lack of hardware to validate on.
> 
> Signed-off-by: Neil Armstrong <[email-masked]>
> ---
>  drivers/usb/dwc3/Kconfig           |  10 +
>  drivers/usb/dwc3/Makefile          |   1 +
>  drivers/usb/dwc3/dwc3-meson-g12a.c | 601 +++++++++++++++++++++++++++++
>  3 files changed, 612 insertions(+)
>  create mode 100644 drivers/usb/dwc3/dwc3-meson-g12a.c
> 
> diff --git a/drivers/usb/dwc3/Kconfig b/drivers/usb/dwc3/Kconfig
> index 1a0404fda596..21ce7368d325 100644
> --- a/drivers/usb/dwc3/Kconfig
> +++ b/drivers/usb/dwc3/Kconfig
> @@ -93,6 +93,16 @@ config USB_DWC3_KEYSTONE
>  	  Support of USB2/3 functionality in TI Keystone2 platforms.
>  	  Say 'Y' or 'M' here if you have one such device
>  
> +config USB_DWC3_MESON_G12A
> +       tristate "Amlogic Meson G12A Platforms"
> +       depends on OF && COMMON_CLK
> +       depends on ARCH_MESON || COMPILE_TEST
> +       default USB_DWC3
> +       select USB_ROLE_SWITCH
> +       help
> +         Support USB2/3 functionality in Amlogic G12A platforms.
> +	 Say 'Y' or 'M' if you have one such device.
> +
>  config USB_DWC3_OF_SIMPLE
>         tristate "Generic OF Simple Glue Layer"
>         depends on OF && COMMON_CLK
> diff --git a/drivers/usb/dwc3/Makefile b/drivers/usb/dwc3/Makefile
> index 6e3ef6144e5d..ae86da0dc5bd 100644
> --- a/drivers/usb/dwc3/Makefile
> +++ b/drivers/usb/dwc3/Makefile
> @@ -47,6 +47,7 @@ obj-$(CONFIG_USB_DWC3_EXYNOS)		+= dwc3-exynos.o
>  obj-$(CONFIG_USB_DWC3_PCI)		+= dwc3-pci.o
>  obj-$(CONFIG_USB_DWC3_HAPS)		+= dwc3-haps.o
>  obj-$(CONFIG_USB_DWC3_KEYSTONE)		+= dwc3-keystone.o
> +obj-$(CONFIG_USB_DWC3_MESON_G12A)	+= dwc3-meson-g12a.o
>  obj-$(CONFIG_USB_DWC3_OF_SIMPLE)	+= dwc3-of-simple.o
>  obj-$(CONFIG_USB_DWC3_ST)		+= dwc3-st.o
>  obj-$(CONFIG_USB_DWC3_QCOM)		+= dwc3-qcom.o
> diff --git a/drivers/usb/dwc3/dwc3-meson-g12a.c b/drivers/usb/dwc3/dwc3-meson-g12a.c
> new file mode 100644
> index 000000000000..75942614a034
> --- /dev/null
> +++ b/drivers/usb/dwc3/dwc3-meson-g12a.c
> @@ -0,0 +1,601 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * USB Glue for Amlogic G12A SoCs
> + *
> + * Copyright (c) 2019 BayLibre, SAS
> + * Author: Neil Armstrong <[email-masked]>
> + */
> +
> +/*
> + * The USB is organized with a glue around the DWC3 Controller IP as :
> + * - Control registers for each USB2 Ports
> + * - Control registers for the USB PHY layer
> + * - SuperSpeed PHY can be enabled only if port is used
> + *
> + * TOFIX:
> + * - Add dynamic OTG switching with ID change interrupt
> + */
> +
[...]
> +
> +static int dwc3_meson_g12a_probe(struct platform_device *pdev)
> +{
> +	struct dwc3_meson_g12a	*priv;
> +	struct device		*dev = &pdev->dev;
> +	struct device_node	*np = dev->of_node;
> +	void __iomem *base;
> +	struct resource *res;
> +	enum phy_mode otg_id;
> +	int ret, i;
> +
> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	base = devm_ioremap_resource(dev, res);
> +	if (IS_ERR(base))
> +		return PTR_ERR(base);
> +
> +	priv->regmap = devm_regmap_init_mmio(dev, base,
> +					     &phy_meson_g12a_usb3_regmap_conf);
> +	if (IS_ERR(priv->regmap))
> +		return PTR_ERR(priv->regmap);
> +
> +	priv->vbus = devm_regulator_get_optional(dev, "vbus");
> +	if (IS_ERR(priv->vbus)) {
> +		if (PTR_ERR(priv->vbus) == -EPROBE_DEFER)
> +			return PTR_ERR(priv->vbus);
> +		priv->vbus = NULL;
> +	}
> +
> +	priv->clk = devm_clk_get(dev, NULL);
> +	if (IS_ERR(priv->clk))
> +		return PTR_ERR(priv->clk);
> +
> +	ret = clk_prepare_enable(priv->clk);
> +	if (ret)
> +		return ret;
> +
> +	platform_set_drvdata(pdev, priv);
> +	priv->dev = dev;
> +
> +	priv->reset = devm_reset_control_get(dev, NULL);
> +	if (IS_ERR(priv->reset)) {
> +		ret = PTR_ERR(priv->reset);
> +		dev_err(dev, "failed to get device reset, err=%d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = reset_control_reset(priv->reset);
> +	if (ret)
> +		return ret;
> +
> +	ret = dwc3_meson_g12a_get_phys(priv);
> +	if (ret)
> +		return ret;
> +
> +	ret = regulator_enable(priv->vbus);
> +	if (ret)
> +		return ret;
> +
> +	/* Get dr_mode */
> +	priv->otg_mode = usb_get_dr_mode(dev);
> +
> +	dwc3_meson_g12a_usb_init(priv);
> +
> +	/* Set PHY Power */
> +	for (i = 0 ; i < PHY_COUNT ; ++i) {
> +		ret = phy_power_on(priv->phys[i]);
> +		if (ret)
> +			goto err_phys_put;
> +	}
> +
> +	/* Init PHYs */
> +	for (i = 0 ; i < PHY_COUNT ; ++i) {
> +		ret = phy_init(priv->phys[i]);
> +		if (ret)
> +			goto err_phys_power;
> +	}
usually phy_init() first

> +
> +	ret = of_platform_populate(np, NULL, NULL, dev);
> +	if (ret) {
> +		clk_disable_unprepare(priv->clk);
> +		clk_put(priv->clk);
> +
> +		goto err_phys_exit;
> +	}
> +
> +	/* Setup OTG mode corresponding to the ID pin */
> +	if (priv->otg_mode == USB_DR_MODE_OTG) {
> +		/* TOFIX Handle ID mode toggling via IRQ */
> +		otg_id = dwc3_meson_g12a_get_id(priv);
> +		if (otg_id != priv->otg_phy_mode) {
> +			if (dwc3_meson_g12a_otg_mode_set(priv, otg_id))
> +				dev_warn(dev, "Failed to switch OTG mode\n");
> +		}
> +	}
> +
> +	/* Setup role switcher */
> +	priv->switch_desc.usb2_port = dwc3_meson_g12_find_child(dev,
> +								"snps,dwc3");
> +	priv->switch_desc.udc = dwc3_meson_g12_find_child(dev, "snps,dwc2");
> +	priv->switch_desc.allow_userspace_control = true;
> +	priv->switch_desc.set = dwc3_meson_g12a_role_set;
> +	priv->switch_desc.get = dwc3_meson_g12a_role_get;
to me, use a local variable for switch_desc

> +
> +	priv->role_switch = usb_role_switch_register(dev, &priv->switch_desc);
> +	if (IS_ERR(priv->role_switch))
> +		dev_warn(dev, "Unable to register Role Switch\n");
> +
> +	pm_runtime_set_active(dev);
> +	pm_runtime_enable(dev);
> +	pm_runtime_get_sync(dev);
> +
> +	return 0;
> +
> +err_phys_exit:
> +	for (i = 0 ; i < PHY_COUNT ; ++i)
> +		phy_exit(priv->phys[i]);
> +
> +err_phys_power:
> +	for (i = 0 ; i < PHY_COUNT ; ++i)
> +		phy_power_off(priv->phys[i]);
> +
> +err_phys_put:
> +	for (i = 0 ; i < PHY_COUNT ; ++i)
> +		phy_put(priv->phys[i]);
> +
The phys are got by devm_phy_optional_get(), no need call phy_put()
> +	return ret;
> +}
> +
> +static int dwc3_meson_g12a_remove(struct platform_device *pdev)
> +{
> +	struct dwc3_meson_g12a *priv = platform_get_drvdata(pdev);
> +	struct device *dev = &pdev->dev;
> +	int i;
> +
> +	usb_role_switch_unregister(priv->role_switch);
> +
> +	of_platform_depopulate(dev);
> +
> +	for (i = 0 ; i < PHY_COUNT ; ++i) {
> +		phy_power_off(priv->phys[i]);
> +		phy_exit(priv->phys[i]);
> +		phy_put(priv->phys[i]);
ditto
> +	}
> +
> +	clk_disable_unprepare(priv->clk);
> +	clk_put(priv->clk);
> +
> +	pm_runtime_disable(dev);
> +	pm_runtime_put_noidle(dev);
> +	pm_runtime_set_suspended(dev);
> +
> +	return 0;
> +}
> +
> +static int __maybe_unused dwc3_meson_g12a_runtime_suspend(struct device *dev)
> +{
> +	struct dwc3_meson_g12a	*priv = dev_get_drvdata(dev);
> +
> +	clk_disable(priv->clk);
> +
> +	return 0;
> +}
> +
> +static int __maybe_unused dwc3_meson_g12a_runtime_resume(struct device *dev)
> +{
> +	struct dwc3_meson_g12a	*priv = dev_get_drvdata(dev);
> +
> +	return clk_enable(priv->clk);
> +}
> +
> +static int __maybe_unused dwc3_meson_g12a_suspend(struct device *dev)
> +{
> +	struct dwc3_meson_g12a *priv = dev_get_drvdata(dev);
> +	int i;
> +
> +	for (i = 0 ; i < PHY_COUNT ; ++i)
> +		if (priv->phys[i])
> +			phy_exit(priv->phys[i]);
> +
> +	reset_control_assert(priv->reset);
> +
> +	return 0;
> +}
> +
> +static int __maybe_unused dwc3_meson_g12a_resume(struct device *dev)
> +{
> +	struct dwc3_meson_g12a *priv = dev_get_drvdata(dev);
> +	int i, ret;
> +
> +	reset_control_deassert(priv->reset);
> +
> +	dwc3_meson_g12a_usb_init(priv);
> +
> +	/* Init PHYs */
> +	for (i = 0 ; i < PHY_COUNT ; ++i) {
> +		if (priv->phys[i]) {
> +			ret = phy_init(priv->phys[i]);
> +			if (ret)
> +				return ret;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct dev_pm_ops dwc3_meson_g12a_dev_pm_ops = {
> +	SET_SYSTEM_SLEEP_PM_OPS(dwc3_meson_g12a_suspend, dwc3_meson_g12a_resume)
> +	SET_RUNTIME_PM_OPS(dwc3_meson_g12a_runtime_suspend,
> +			dwc3_meson_g12a_runtime_resume, NULL)
> +};
> +
> +static const struct of_device_id dwc3_meson_g12a_match[] = {
> +	{ .compatible = "amlogic,meson-g12a-usb-ctrl" },
> +	{ /* Sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, dwc3_meson_g12a_match);
> +
> +static struct platform_driver dwc3_meson_g12a_driver = {
> +	.probe		= dwc3_meson_g12a_probe,
> +	.remove		= dwc3_meson_g12a_remove,
> +	.driver		= {
> +		.name	= "dwc3-meson-g12a",
> +		.of_match_table = dwc3_meson_g12a_match,
> +		.pm	= &dwc3_meson_g12a_dev_pm_ops,
> +	},
> +};
> +
> +module_platform_driver(dwc3_meson_g12a_driver);
> +MODULE_LICENSE("GPL v2");
> +MODULE_DESCRIPTION("Amlogic Meson G12A USB Glue Layer");
> +MODULE_AUTHOR("Neil Armstrong <[email-masked]>");

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