Message-ID: <16e3c1c7-f2df-984f-1965-a4b48a9094be@ti.com>
Date:   Wed, 16 Aug 2017 19:27:49 +0530
From:   Kishon Vijay Abraham I <kishon@...com>
To:     Harvey Hunt <harvey.hunt@...tec.com>, <robh+dt@...nel.org>,
        <mark.rutland@....com>, <matthias.bgg@...il.com>
CC:     <james.hogan@...tec.com>, John Crispin <john@...ozen.org>,
        <linux-kernel@...r.kernel.org>,
        <linux-mediatek@...ts.infradead.org>
Subject: Re: [V6 1/2] phy: ralink-usb: add driver for Mediatek/Ralink

Hi,

On Tuesday 15 August 2017 06:17 PM, Harvey Hunt wrote:
> From: John Crispin <john@...ozen.org>
> 
> Add a driver to setup the USB phy on Mediatek/Ralink SoCs.
> The driver sets up power and host mode, but also needs to
> configure PHY registers for the MT7628 and MT7688.
> 
> Signed-off-by: John Crispin <john@...ozen.org>
> Signed-off-by: Harvey Hunt <harvey.hunt@...tec.com>
> Cc: linux-kernel@...r.kernel.org
> Cc: linux-mediatek@...ts.infradead.org
> ---
> Changes in V6
> * Add binding for MT7628
> * Configure PHY registers for MT76{2,8}8
> 
> Changes in V5
> * Depend on MIPS
> 
> Changes in V4
> * Remove Allwinner from comment
> * Depend on COMPILE_TEST
> 
> Changes in V3
> * Separate DT bindings
> * Update Kconfig text
> * Modify John's email address
> * Rebase onto v4.13-rc3
> 
> Changes in V2
> * remove refcounting
> * drop empty functions
> * dont use static globals
> * use explicit compatible strings
> 
>  drivers/phy/Kconfig          |   9 ++
>  drivers/phy/Makefile         |   1 +
>  drivers/phy/phy-ralink-usb.c | 238 +++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 248 insertions(+)
>  create mode 100644 drivers/phy/phy-ralink-usb.c
> 
> diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
> index c1807d4..a95394b 100644
> --- a/drivers/phy/Kconfig
> +++ b/drivers/phy/Kconfig
> @@ -41,6 +41,15 @@ config PHY_PISTACHIO_USB
>  	help
>  	  Enable this to support the USB2.0 PHY on the IMG Pistachio SoC.
>  
> +config PHY_RALINK_USB
> +	tristate "Ralink USB PHY driver"
> +	depends on RALINK || COMPILE_TEST
> +	depends on MIPS

depends on (RALINK && MIPS) || COMPILE_TEST ??
> +	select GENERIC_PHY
> +	help
> +	  This option enables support for the Ralink USB PHY found inside
> +	  RT3352, MT7620, MT7628 and MT7688.
> +
>  config PHY_XGENE
>  	tristate "APM X-Gene 15Gbps PHY support"
>  	depends on HAS_IOMEM && OF && (ARM64 || COMPILE_TEST)
> diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
> index f252201..60ed30b 100644
> --- a/drivers/phy/Makefile
> +++ b/drivers/phy/Makefile
> @@ -7,6 +7,7 @@ obj-$(CONFIG_PHY_LPC18XX_USB_OTG)	+= phy-lpc18xx-usb-otg.o
>  obj-$(CONFIG_PHY_MT65XX_USB3)		+= phy-mt65xx-usb3.o
>  obj-$(CONFIG_PHY_XGENE)			+= phy-xgene.o
>  obj-$(CONFIG_PHY_PISTACHIO_USB)		+= phy-pistachio-usb.o
> +obj-$(CONFIG_PHY_RALINK_USB)		+= phy-ralink-usb.o
>  
>  obj-$(CONFIG_ARCH_SUNXI)		+= allwinner/
>  obj-$(CONFIG_ARCH_MESON)		+= amlogic/
> diff --git a/drivers/phy/phy-ralink-usb.c b/drivers/phy/phy-ralink-usb.c
> new file mode 100644
> index 0000000..d027c43
> --- /dev/null
> +++ b/drivers/phy/phy-ralink-usb.c

We have separate directories for every vendor. Care to add a new directory for
ralink?
> @@ -0,0 +1,238 @@
> +/*
> + * Copyright (C) 2016 John Crispin <john@...ozen.org>

2017
> + *
> + * 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>

Er.. I think we can't add COMPILE_TEST with this. Why do you have to include
arch specific headers?
> +
> +#define RT_SYSC_REG_SYSCFG1		0x014
> +#define RT_SYSC_REG_CLKCFG1		0x030
> +#define RT_SYSC_REG_USB_PHY_CFG		0x05c
> +
> +#define OFS_U2_PHY_AC0			0x800
> +#define OFS_U2_PHY_AC1			0x804
> +#define OFS_U2_PHY_AC2			0x808
> +#define OFS_U2_PHY_ACR0			0x810
> +#define OFS_U2_PHY_ACR1			0x814
> +#define OFS_U2_PHY_ACR2			0x818
> +#define OFS_U2_PHY_ACR3			0x81C
> +#define OFS_U2_PHY_ACR4			0x820
> +#define OFS_U2_PHY_AMON0		0x824
> +#define OFS_U2_PHY_DCR0			0x860
> +#define OFS_U2_PHY_DCR1			0x864
> +#define OFS_U2_PHY_DTM0			0x868
> +#define OFS_U2_PHY_DTM1			0x86C
> +
> +#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)
> +
> +struct ralink_usb_phy {
> +	struct reset_control	*rstdev;
> +	struct reset_control	*rsthost;
> +	u32			clk;
> +	struct phy		*phy;
> +	void __iomem		*base;
> +};
> +
> +static void u2_phy_w32(struct ralink_usb_phy *phy, u32 val, u32 reg)
> +{
> +	iowrite32(val, phy->base + reg);
> +}

Why iowrite?
> +
> +static u32 u2_phy_r32(struct ralink_usb_phy *phy, u32 reg)
> +{
> +	return ioread32(phy->base + reg);
> +}
> +
> +static void ralink_usb_phy_init(struct ralink_usb_phy *phy)
> +{
> +	u2_phy_r32(phy, OFS_U2_PHY_AC2);
> +	u2_phy_r32(phy, OFS_U2_PHY_ACR0);
> +	u2_phy_r32(phy, OFS_U2_PHY_DCR0);
> +
> +	u2_phy_w32(phy, 0x00ffff02, OFS_U2_PHY_DCR0);
> +	u2_phy_r32(phy, OFS_U2_PHY_DCR0);
> +	u2_phy_w32(phy, 0x00555502, OFS_U2_PHY_DCR0);
> +	u2_phy_r32(phy, OFS_U2_PHY_DCR0);
> +	u2_phy_w32(phy, 0x00aaaa02, OFS_U2_PHY_DCR0);
> +	u2_phy_r32(phy, OFS_U2_PHY_DCR0);
> +	u2_phy_w32(phy, 0x00000402, OFS_U2_PHY_DCR0);
> +	u2_phy_r32(phy, OFS_U2_PHY_DCR0);
> +	u2_phy_w32(phy, 0x0048086a, OFS_U2_PHY_AC0);
> +	u2_phy_w32(phy, 0x4400001c, OFS_U2_PHY_AC1);
> +	u2_phy_w32(phy, 0xc0200000, OFS_U2_PHY_ACR3);
> +	u2_phy_w32(phy, 0x02000000, OFS_U2_PHY_DTM0);

That's too many magic values. But I guess I'm getting used to such
configurations in PHY drivers.
> +}
> +
> +static int ralink_usb_phy_power_on(struct phy *_phy)
> +{
> +	struct ralink_usb_phy *phy = phy_get_drvdata(_phy);
> +	u32 t;
> +
> +	/* enable the phy */
> +	rt_sysc_m32(0, phy->clk, RT_SYSC_REG_CLKCFG1);
> +
> +	/* setup host mode */
> +	rt_sysc_m32(0, RT_SYSCFG1_USB0_HOST_MODE, RT_SYSC_REG_SYSCFG1);

Instead of such arch-specific functions, why not use regmap API's?
> +
> +	/* deassert the reset lines */
> +	reset_control_deassert(phy->rsthost);
> +	reset_control_deassert(phy->rstdev);
> +
> +	/*
> +	 * The SDK kernel had a delay of 100ms. however on device
> +	 * testing showed that 10ms is enough
> +	 */
> +	mdelay(10);
> +
> +	if (phy->base)
> +		ralink_usb_phy_init(phy);
> +
> +	/* print some status info */
> +	t = rt_sysc_r32(RT_SYSC_REG_USB_PHY_CFG);
> +	dev_info(&phy->phy->dev, "remote usb device wakeup %s\n",
> +		(t & UDEV_WAKEUP) ? ("enabled") : ("disabled"));
> +	if (t & USB_PHY_UTMI_8B60M)
> +		dev_info(&phy->phy->dev, "UTMI 8bit 60MHz\n");
> +	else
> +		dev_info(&phy->phy->dev, "UTMI 16bit 30MHz\n");
> +
> +	return 0;
> +}
> +
> +static int ralink_usb_phy_power_off(struct phy *_phy)
> +{
> +	struct ralink_usb_phy *phy = phy_get_drvdata(_phy);
> +
> +	/* disable the phy */
> +	rt_sysc_m32(phy->clk, 0, RT_SYSC_REG_CLKCFG1);
> +
> +	/* assert the reset lines */
> +	reset_control_assert(phy->rstdev);
> +	reset_control_assert(phy->rsthost);
> +
> +	return 0;
> +}
> +
> +static struct phy_ops ralink_usb_phy_ops = {
> +	.power_on	= ralink_usb_phy_power_on,
> +	.power_off	= ralink_usb_phy_power_off,
> +	.owner		= THIS_MODULE,
> +};
> +
> +static const struct of_device_id ralink_usb_phy_of_match[] = {
> +	{
> +		.compatible = "ralink,rt3352-usbphy",
> +		.data = (void *) (RT_CLKCFG1_UPHY1_CLK_EN |
> +				  RT_CLKCFG1_UPHY0_CLK_EN)
> +	},
> +	{
> +		.compatible = "mediatek,mt7620-usbphy",
> +		.data = (void *) (MT7620_CLKCFG1_UPHY1_CLK_EN |
> +				  MT7620_CLKCFG1_UPHY0_CLK_EN)
> +	},
> +	{
> +		.compatible = "mediatek,mt7628-usbphy",
> +		.data = (void *) (MT7620_CLKCFG1_UPHY1_CLK_EN |
> +				  MT7620_CLKCFG1_UPHY0_CLK_EN) },
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(of, ralink_usb_phy_of_match);
> +
> +static int ralink_usb_phy_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct resource *res;
> +	struct phy_provider *phy_provider;
> +	const struct of_device_id *match;
> +	struct ralink_usb_phy *phy;
> +
> +	phy = devm_kzalloc(dev, sizeof(*phy), GFP_KERNEL);
> +	if (!phy)
> +		return -ENOMEM;
> +
> +	match = of_match_device(ralink_usb_phy_of_match, &pdev->dev);
> +	if (!match)
> +		return -ENODEV;

It's usual to have of_match_device before anything else in probe.

Thanks
Kishon

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