linux-kernel - Re: [PATCH v2 7/9] phy: allwinner: add phy driver for USB3 PHY on Allwinner H6 SoC

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Message-ID: <438f1123-a619-61d0-36cd-d65c1430435a@ti.com>
Date:   Mon, 9 Jul 2018 10:01:24 +0530
From:   Kishon Vijay Abraham I <kishon@...com>
To:     Icenowy Zheng <icenowy@...c.io>, Rob Herring <robh+dt@...nel.org>,
        Maxime Ripard <maxime.ripard@...tlin.com>,
        Chen-Yu Tsai <wens@...e.org>
CC:     <devicetree@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <linux-sunxi@...glegroups.com>
Subject: Re: [PATCH v2 7/9] phy: allwinner: add phy driver for USB3 PHY on
 Allwinner H6 SoC

Hi,

On Friday 06 July 2018 09:08 PM, Icenowy Zheng wrote:
> Allwinner H6 SoC contains a USB3 PHY (with USB2 DP/DM lines also
> controlled).
> 
> Add a driver for it.
> 
> The register operations in this driver is mainly extracted from the BSP
> USB3 driver.
> 
> Signed-off-by: Icenowy Zheng <icenowy@...c.io>
> ---
> Changes in v2:
> - Splitted out the DT binding.
> 
>  drivers/phy/allwinner/Kconfig           |  13 ++
>  drivers/phy/allwinner/Makefile          |   1 +
>  drivers/phy/allwinner/phy-sun50i-usb3.c | 194 ++++++++++++++++++++++++
>  3 files changed, 208 insertions(+)
>  create mode 100644 drivers/phy/allwinner/phy-sun50i-usb3.c
> 
> diff --git a/drivers/phy/allwinner/Kconfig b/drivers/phy/allwinner/Kconfig
> index cdc1e745ba47..cf373bcee034 100644
> --- a/drivers/phy/allwinner/Kconfig
> +++ b/drivers/phy/allwinner/Kconfig
> @@ -29,3 +29,16 @@ config PHY_SUN9I_USB
>  	  sun9i SoCs.
>  
>  	  This driver controls each individual USB 2 host PHY.
> +
> +config PHY_SUN50I_USB3
> +	tristate "Allwinner sun50i SoC USB3 PHY driver"
> +	depends on ARCH_SUNXI && HAS_IOMEM && OF
> +	depends on RESET_CONTROLLER
> +	depends on USB_SUPPORT
> +	select USB_COMMON

Doesn't look like this driver depends on USB_SUPPORT.
> +	select GENERIC_PHY
> +	help
> +	  Enable this to support the USB3.0-capable transceiver that is
> +	  part of some Allwinner sun50i SoCs.
> +
> +	  This driver controls each individual USB 2+3 host PHY combo.
> diff --git a/drivers/phy/allwinner/Makefile b/drivers/phy/allwinner/Makefile
> index 8605529c01a1..a8d01e9073c2 100644
> --- a/drivers/phy/allwinner/Makefile
> +++ b/drivers/phy/allwinner/Makefile
> @@ -1,2 +1,3 @@
>  obj-$(CONFIG_PHY_SUN4I_USB)		+= phy-sun4i-usb.o
>  obj-$(CONFIG_PHY_SUN9I_USB)		+= phy-sun9i-usb.o
> +obj-$(CONFIG_PHY_SUN50I_USB3)		+= phy-sun50i-usb3.o
> diff --git a/drivers/phy/allwinner/phy-sun50i-usb3.c b/drivers/phy/allwinner/phy-sun50i-usb3.c
> new file mode 100644
> index 000000000000..226c99c2d664
> --- /dev/null
> +++ b/drivers/phy/allwinner/phy-sun50i-usb3.c
> @@ -0,0 +1,194 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Allwinner sun50i(H6) USB 3.0 phy driver
> + *
> + * Copyright (C) 2017 Icenowy Zheng <icenowy@...c.io>
> + *
> + * Based on phy-sun9i-usb.c, which is:
> + *
> + * Copyright (C) 2014-2015 Chen-Yu Tsai <wens@...e.org>
> + *
> + * Based on code from Allwinner BSP, which is:
> + *
> + * Copyright (c) 2010-2015 Allwinner Technology Co., Ltd.

Does the BSP also use GPL license?
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/phy/phy.h>
> +#include <linux/usb/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/reset.h>
> +
> +/* Interface Status and Control Registers */
> +#define SUNXI_ISCR			0x00
> +#define SUNXI_PIPE_CLOCK_CONTROL	0x14
> +#define SUNXI_PHY_TUNE_LOW		0x18
> +#define SUNXI_PHY_TUNE_HIGH		0x1c
> +#define SUNXI_PHY_EXTERNAL_CONTROL	0x20
> +
> +/* USB2.0 Interface Status and Control Register */
> +#define SUNXI_ISCR_FORCE_VBUS		(3 << 12)
> +
> +/* PIPE Clock Control Register */
> +#define SUNXI_PCC_PIPE_CLK_OPEN		(1 << 6)
> +
> +/* PHY External Control Register */
> +#define SUNXI_PEC_EXTERN_VBUS		(3 << 1)
> +#define SUNXI_PEC_SSC_EN		(1 << 24)
> +#define SUNXI_PEC_REF_SSP_EN		(1 << 26)
> +
> +/* PHY Tune High Register */
> +#define SUNXI_TX_DEEMPH_3P5DB(n)	((n) << 19)
> +#define SUNXI_TX_DEEMPH_3P5DB_MASK	GENMASK(24, 19)
> +#define SUNXI_TX_DEEMPH_6DB(n)		((n) << 13)
> +#define SUNXI_TX_DEEMPH_6GB_MASK	GENMASK(18, 13)
> +#define SUNXI_TX_SWING_FULL(n)		((n) << 6)
> +#define SUNXI_TX_SWING_FULL_MASK	GENMASK(12, 6)
> +#define SUNXI_LOS_BIAS(n)		((n) << 3)
> +#define SUNXI_LOS_BIAS_MASK		GENMASK(5, 3)
> +#define SUNXI_TXVBOOSTLVL(n)		((n) << 0)
> +#define SUNXI_TXVBOOSTLVL_MASK		GENMASK(0, 2)
> +
> +struct sun50i_usb3_phy {
> +	struct phy *phy;
> +	void __iomem *regs;
> +	struct reset_control *reset;
> +	struct clk *clk;
> +};
> +
> +static void sun50i_usb3_phy_open(struct sun50i_usb3_phy *phy)
> +{
> +	u32 val;
> +
> +	val = readl(phy->regs + SUNXI_PHY_EXTERNAL_CONTROL);
> +	val |= SUNXI_PEC_EXTERN_VBUS;
> +	val |= SUNXI_PEC_SSC_EN | SUNXI_PEC_REF_SSP_EN;
> +	writel(val, phy->regs + SUNXI_PHY_EXTERNAL_CONTROL);
> +
> +	val = readl(phy->regs + SUNXI_PIPE_CLOCK_CONTROL);
> +	val |= SUNXI_PCC_PIPE_CLK_OPEN;
> +	writel(val, phy->regs + SUNXI_PIPE_CLOCK_CONTROL);
> +
> +	val = readl(phy->regs + SUNXI_ISCR);
> +	val |= SUNXI_ISCR_FORCE_VBUS;
> +	writel(val, phy->regs + SUNXI_ISCR);
> +
> +	/*
> +	 * All the magic numbers written to the PHY_TUNE_{LOW_HIGH}
> +	 * registers are directly taken from the BSP USB3 driver from
> +	 * Allwiner.

%s/Allwiner/Allwinner/
> +	 */
> +	writel(0x0047fc87, phy->regs + SUNXI_PHY_TUNE_LOW);

PHY_TUNE_LOW should also configure individual parameters like how you've done
below for PHY_TUNE_HIGH.

Thanks
Kishon