Re: [PATCH] phy: ralink-usb: add driver for Mediatek/Ralink

[Kishon Vijay Abraham I <kishon@ti.com>]

Hi,

On Wednesday 04 November 2015 04:24 PM, John Crispin wrote:
> Add a driver to setup the USB phy on Mediatek/Ralink SoCs.
> The driver is trivial and only sets the power and host/device mode.
> 
> Signed-off-by: John Crispin <blogic@openwrt.org>
> ---
>  .../devicetree/bindings/phy/ralink-usb-phy.txt     |   17 ++
>  drivers/phy/Kconfig                                |    7 +
>  drivers/phy/Makefile                               |    1 +
>  drivers/phy/phy-ralink-usb.c                       |  183 ++++++++++++++++++++
>  4 files changed, 208 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/phy/ralink-usb-phy.txt
>  create mode 100644 drivers/phy/phy-ralink-usb.c
> 
> diff --git a/Documentation/devicetree/bindings/phy/ralink-usb-phy.txt b/Documentation/devicetree/bindings/phy/ralink-usb-phy.txt
> new file mode 100644
> index 0000000..363cff0
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/phy/ralink-usb-phy.txt
> @@ -0,0 +1,17 @@
> +Mediatek/Ralink USB PHY
> +
> +Required properties:
> + - compatible: ralink,rt3xxx-usbphy or ralink,mt7620-usbphy

is *ralink,rt3xxx-usbphy* really needed.
> + - #phy-cells: should be 0
> + - resets: the two reset controllers for host and device
> + - reset-names: the names of the 2 reset controllers
> +
> +Example:
> +
> +usbphy: phy {
> +	compatible = "ralink,mt7620a-usbphy";
> +	#phy-cells = <0>;
> +
> +	resets = <&rstctrl 22 &rstctrl 25>;
> +	reset-names = "host", "device";
> +};
> diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
> index 47da573..01e4df4 100644
> --- a/drivers/phy/Kconfig
> +++ b/drivers/phy/Kconfig
> @@ -331,6 +331,13 @@ config PHY_XGENE
>  	help
>  	  This option enables support for APM X-Gene SoC multi-purpose PHY.
>  
> +config PHY_RALINK_USB
> +	tristate "Ralink USB PHY driver"
> +	select GENERIC_PHY
> +	depends on RALINK
> +	help
> +	  This option enables support for Ralink SoC USB PHY.
> +
>  config PHY_STIH407_USB
>  	tristate "STMicroelectronics USB2 picoPHY driver for STiH407 family"
>  	depends on RESET_CONTROLLER
> diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
> index a5b18c1..8dbf6cc 100644
> --- a/drivers/phy/Makefile
> +++ b/drivers/phy/Makefile
> @@ -46,3 +46,4 @@ obj-$(CONFIG_PHY_QCOM_UFS) 	+= phy-qcom-ufs-qmp-14nm.o
>  obj-$(CONFIG_PHY_TUSB1210)		+= phy-tusb1210.o
>  obj-$(CONFIG_PHY_BRCMSTB_SATA)		+= phy-brcmstb-sata.o
>  obj-$(CONFIG_PHY_PISTACHIO_USB)		+= phy-pistachio-usb.o
> +obj-$(CONFIG_PHY_RALINK_USB)		+= phy-ralink-usb.o
> diff --git a/drivers/phy/phy-ralink-usb.c b/drivers/phy/phy-ralink-usb.c
> new file mode 100644
> index 0000000..d3b590b
> --- /dev/null
> +++ b/drivers/phy/phy-ralink-usb.c
> @@ -0,0 +1,183 @@
> +/*
> + * Ralink USB phy driver
> + *
> + * Copyright (C) 2014 John Crispin <blogic@openwrt.org>

2015..
> + *
> + * Based on code from
> + * Allwinner Technology Co., Ltd. <www.allwinnertech.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/phy/phy.h>
> +#include <linux/platform_device.h>
> +#include <linux/reset.h>
> +#include <linux/of_platform.h>
> +
> +#include <asm/mach-ralink/ralink_regs.h>
> +
> +#define RT_SYSC_REG_SYSCFG1		0x014
> +#define RT_SYSC_REG_CLKCFG1		0x030
> +#define RT_SYSC_REG_USB_PHY_CFG		0x05c
> +
> +#define RT_RSTCTRL_UDEV			BIT(25)
> +#define RT_RSTCTRL_UHST			BIT(22)
> +#define RT_SYSCFG1_USB0_HOST_MODE	BIT(10)
> +
> +#define MT7620_CLKCFG1_UPHY0_CLK_EN	BIT(25)
> +#define MT7620_CLKCFG1_UPHY1_CLK_EN	BIT(22)
> +#define RT_CLKCFG1_UPHY1_CLK_EN		BIT(20)
> +#define RT_CLKCFG1_UPHY0_CLK_EN		BIT(18)
> +
> +#define USB_PHY_UTMI_8B60M		BIT(1)
> +#define UDEV_WAKEUP			BIT(0)
> +
> +static atomic_t usb_pwr_ref = ATOMIC_INIT(0);
> +static struct reset_control *rstdev;
> +static struct reset_control *rsthost;
> +static u32 phy_clk;
> +static struct phy *rt_phy;

Avoid using global variable. These are not required to be global at all.
> +
> +static void usb_phy_enable(int state)
> +{
> +	if (state)
> +		rt_sysc_m32(0, phy_clk, RT_SYSC_REG_CLKCFG1);
> +	else
> +		rt_sysc_m32(phy_clk, 0, RT_SYSC_REG_CLKCFG1);
> +	mdelay(100);
> +}
> +
> +static int ralink_usb_phy_init(struct phy *_phy)
> +{
> +	return 0;
> +}
> +
> +static int ralink_usb_phy_exit(struct phy *_phy)
> +{
> +	return 0;
> +}

These empty functions are not required.
> +
> +static int ralink_usb_phy_power_on(struct phy *_phy)
> +{
> +	if (atomic_inc_return(&usb_pwr_ref) == 1) {

Why do you need this? Is the reference counting provided in phy-core not enough?


> +		int host = 1;
> +		u32 t;
> +
> +		usb_phy_enable(1);
> +
> +		if (host) {
> +			rt_sysc_m32(0, RT_SYSCFG1_USB0_HOST_MODE,
> +				       RT_SYSC_REG_SYSCFG1);
> +			if (!IS_ERR(rsthost))
> +				reset_control_deassert(rsthost);
> +			if (!IS_ERR(rstdev))
> +				reset_control_deassert(rstdev);
> +		} else {
> +			rt_sysc_m32(RT_SYSCFG1_USB0_HOST_MODE, 0,
> +				    RT_SYSC_REG_SYSCFG1);
> +			if (!IS_ERR(rstdev))
> +				reset_control_deassert(rstdev);
> +		}
> +		mdelay(100);
> +
> +		t = rt_sysc_r32(RT_SYSC_REG_USB_PHY_CFG);
> +		dev_info(&_phy->dev, "remote usb device wakeup %s\n",
> +			(t & UDEV_WAKEUP) ? ("enabbled") : ("disabled"));
> +		if (t & USB_PHY_UTMI_8B60M)
> +			dev_info(&_phy->dev, "UTMI 8bit 60MHz\n");
> +		else
> +			dev_info(&_phy->dev, "UTMI 16bit 30MHz\n");
> +	}
> +
> +	return 0;
> +}
> +
> +static int ralink_usb_phy_power_off(struct phy *_phy)
> +{
> +	if (atomic_dec_return(&usb_pwr_ref) == 0) {
> +		usb_phy_enable(0);
> +		if (!IS_ERR(rstdev))
> +			reset_control_assert(rstdev);
> +		if (!IS_ERR(rsthost))
> +			reset_control_assert(rsthost);
> +	}
> +
> +	return 0;
> +}
> +
> +static struct phy_ops ralink_usb_phy_ops = {
> +	.init		= ralink_usb_phy_init,
> +	.exit		= ralink_usb_phy_exit,
> +	.power_on	= ralink_usb_phy_power_on,
> +	.power_off	= ralink_usb_phy_power_off,
> +	.owner		= THIS_MODULE,
> +};
> +
> +static struct phy *ralink_usb_phy_xlate(struct device *dev,
> +					struct of_phandle_args *args)
> +{
> +	return rt_phy;
> +}

weird.. why do you need empty xlate function? use of_phy_simple_xlate.
> +
> +static const struct of_device_id ralink_usb_phy_of_match[] = {
> +	{
> +		.compatible = "ralink,rt3xxx-usbphy",

Use a specific compatible string. Which SoC's should use "ralink,rt3xxx-usbphy"?

Thanks
Kishon