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Subject: Re: [PATCH v2 8/8] usb: dwc3: Add Amlogic G12A DWC3 glue
To:     Chunfeng Yun <chunfeng.yun@mediatek.com>
Cc:     gregkh@linuxfoundation.org, hminas@synopsys.com, balbi@kernel.org,
        kishon@ti.com, linux-amlogic@lists.infradead.org,
        linux-usb@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org
References: <20190304103846.2060-1-narmstrong@baylibre.com>
 <20190304103846.2060-9-narmstrong@baylibre.com>
 <1551924176.2210.104.camel@mhfsdcap03>
From:   Neil Armstrong <narmstrong@baylibre.com>
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Organization: Baylibre
Message-ID: <6eaff413-d2c7-125a-f165-e4226c7a153e@baylibre.com>
Date:   Thu, 7 Mar 2019 10:45:56 +0100
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Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 07/03/2019 03:02, Chunfeng Yun wrote:
> 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 <narmstrong@baylibre.com>
>> ---
>>  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 <narmstrong@baylibre.com>
>> + */
>> +
>> +/*
>> + * 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

OK, i usually saw power_on before, but I'll swap them.

> 
>> +
>> +	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

I'm never fan of changing a local global variable for a driver instance,
is it strictly required ?

> 
>> +
>> +	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()

You are right, this is a leftover from v1.

>> +	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

Thanks for the review,
Neil

>> +	}
>> +
>> +	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 <narmstrong@baylibre.com>");
> 
>