Subject: [PATCH v2] ARM: sunxi: Add driver for sunxi usb phy

From: [email-masked] (Maxime Ripard)
Date: Mon, 10 Feb 2014 21:43:08 +0100

Hi,

On Sat, Feb 08, 2014 at 12:27:42AM +0100, Hans de Goede wrote:
> Hi,
> 
> On 02/07/2014 11:36 PM, Maxime Ripard wrote:
> >Hi Hans,
> >
> >It looks very nice, I just have a few comments below though.
> >
> >On Fri, Feb 07, 2014 at 05:33:21PM +0100, Hans de Goede wrote:
> >>The Allwinner A1x / A2x SoCs have 2 or 3 usb phys which are all accessed
> >>through a single set of registers. Besides this there are also some other
> >>phy related bits which need poking, which are per phy, but shared between the
> >>ohci and ehci controllers, so these are also controlled from this new phy
> >>driver.
> >>
> >>Signed-off-by: Hans de Goede <[email-masked]>
> >>---
> >>  .../devicetree/bindings/phy/sun4i-usb-phy.txt      |  28 ++
> >>  drivers/phy/Kconfig                                |  11 +
> >>  drivers/phy/Makefile                               |   1 +
> >>  drivers/phy/phy-sun4i-usb.c                        | 326 +++++++++++++++++++++
> >>  4 files changed, 366 insertions(+)
> >>  create mode 100644 Documentation/devicetree/bindings/phy/sun4i-usb-phy.txt
> >>  create mode 100644 drivers/phy/phy-sun4i-usb.c
> >>
> >>diff --git a/Documentation/devicetree/bindings/phy/sun4i-usb-phy.txt b/Documentation/devicetree/bindings/phy/sun4i-usb-phy.txt
> >>new file mode 100644
> >>index 0000000..f7eccb2
> >>--- /dev/null
> >>+++ b/Documentation/devicetree/bindings/phy/sun4i-usb-phy.txt
> >>@@ -0,0 +1,28 @@
> >>+Allwinner sun4i USB PHY
> >>+-----------------------
> >>+
> >>+Required properties:
> >>+- compatible : should be one of "allwinner,sun4i-a10-usb-phy",
> >>+  "allwinner,sun5i-a13-usb-phy" or "allwinner,sun7i-a20-usb-phy"
> >>+- reg : a list of offset + length pairs, the 1st list entry should point to
> >>+  the phy base regs, the 2nd entry to the pmu reg for phy1, and the 3th
> >>+  entry to the pmu reg of phy2 (for devices which have a phy2).
> >
> >I'm concerned about devices that would only have a phy2 for some
> >reason.
> 
> phy1 and phy2 are identical, so in that case we would just call the phy
> phy1 I guess, and specify its register where ever it lives and be done with
> it.
> 
> >Using reg-names would be much more robust, and is quite painless to
> >use. Just use platform_get_resource_by_name instead of
> >platform_get_resource, and that's pretty much it.
> 
> The above argument does not really help to convince me to use
> register-names, I don't really see them as useful / necessary,
> adding support for them will just grow the driver-code, as well
> as the devicetree bindings docs, as well as the dts files.
> 
> But if you really really want me to use register-names, just say so
> and I'll modify the patch.

Yep, overall, whenever there's several resources involved, I very much
prefer to differentiate them by name, rather than by index, which is
much more fragile.

And the overhead is of one single line in the DT, one single line in
the doc, and a few of them in the driver. It doesn't look like it
bloats the code that much...

> 
> 
> >
> >>+- #phy-cells : from the generic phy bindings, must be 1
> >>+
> >>+Optional properties:
> >>+- clocks : phandle + clock specifier for the phy clock
> >>+- clock-names : "usb_phy"
> >>+- resets : a list of phandle + reset specifier pairs
> >>+- reset-names : "usb0_reset", "usb1_reset", and / or "usb2_reset"
> >>+
> >>+Example:
> >>+	usbphy: phy at 0x01c13400 {
> >>+		#phy-cells = <1>;
> >>+		compatible = "allwinner,sun4i-a10-usb-phy";
> >>+		/* phy base regs, phy1 pmu reg, phy2 pmu reg */
> >>+		reg = <0x01c13400 0x10 0x01c14800 0x4 0x01c1c800 0x4>;
> >>+		clocks = <&usb_clk 8>;
> >>+		clock-names = "usb_phy";
> >>+		resets = <&usb_clk 1>, <&usb_clk 2>;
> >>+		reset-names = "usb1_reset", "usb2_reset";
> >>+	};
> >>diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
> >>index afa2354..6070c99 100644
> >>--- a/drivers/phy/Kconfig
> >>+++ b/drivers/phy/Kconfig
> >>@@ -64,4 +64,15 @@ config BCM_KONA_USB2_PHY
> >>  	help
> >>  	  Enable this to support the Broadcom Kona USB 2.0 PHY.
> >>
> >>+config PHY_SUN4I_USB
> >>+	tristate "Allwinner sunxi SoC USB PHY driver"
> >>+	depends on ARCH_SUNXI
> >>+	select GENERIC_PHY
> >>+	help
> >>+	  Enable this to support the transceiver that is part of Allwinner
> >>+	  sunxi SoCs.
> >>+
> >>+	  This driver controls the entire USB PHY block, both the USB OTG
> >>+	  parts, as well as the 2 regular USB 2 host PHYs.
> >>+
> >>  endmenu
> >>diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
> >>index b57c253..9d4f8bb 100644
> >>--- a/drivers/phy/Makefile
> >>+++ b/drivers/phy/Makefile
> >>@@ -9,3 +9,4 @@ obj-$(CONFIG_PHY_EXYNOS_MIPI_VIDEO)	+= phy-exynos-mipi-video.o
> >>  obj-$(CONFIG_PHY_MVEBU_SATA)		+= phy-mvebu-sata.o
> >>  obj-$(CONFIG_OMAP_USB2)			+= phy-omap-usb2.o
> >>  obj-$(CONFIG_TWL4030_USB)		+= phy-twl4030-usb.o
> >>+obj-$(CONFIG_PHY_SUN4I_USB)		+= phy-sun4i-usb.o
> >>diff --git a/drivers/phy/phy-sun4i-usb.c b/drivers/phy/phy-sun4i-usb.c
> >>new file mode 100644
> >>index 0000000..bd9cb7fa
> >>--- /dev/null
> >>+++ b/drivers/phy/phy-sun4i-usb.c
> >>@@ -0,0 +1,326 @@
> >>+/*
> >>+ * Allwinner sun4i USB phy driver
> >>+ *
> >>+ * Copyright (C) 2014 Hans de Goede <[email-masked]>
> >>+ *
> >>+ * Based on code from
> >>+ * Allwinner Technology Co., Ltd. <www.allwinnertech.com>
> >>+ *
> >>+ * Modelled after: Samsung S5P/EXYNOS SoC series MIPI CSIS/DSIM DPHY driver
> >>+ * Copyright (C) 2013 Samsung Electronics Co., Ltd.
> >>+ * Author: Sylwester Nawrocki <[email-masked]>
> >>+ *
> >>+ * 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/clk.h>
> >>+#include <linux/io.h>
> >>+#include <linux/kernel.h>
> >>+#include <linux/module.h>
> >>+#include <linux/mutex.h>
> >>+#include <linux/of.h>
> >>+#include <linux/of_address.h>
> >>+#include <linux/phy/phy.h>
> >>+#include <linux/platform_device.h>
> >>+#include <linux/regulator/consumer.h>
> >>+#include <linux/reset.h>
> >>+
> >>+#define REG_ISCR			0x00
> >>+#define REG_PHYCTL			0x04
> >>+#define REG_PHYBIST			0x08
> >>+#define REG_PHYTUNE			0x0c
> >>+
> >>+#define SUNXI_AHB_ICHR8_EN		BIT(10)
> >>+#define SUNXI_AHB_INCR4_BURST_EN	BIT(9)
> >>+#define SUNXI_AHB_INCRX_ALIGN_EN	BIT(8)
> >>+#define SUNXI_ULPI_BYPASS_EN		BIT(0)
> >>+
> >>+/* Common Control Bits for Both PHYs */
> >>+#define PHY_PLL_BW			0x03
> >>+#define PHY_RES45_CAL_EN		0x0c
> >>+
> >>+/* Private Control Bits for Each PHY */
> >>+#define PHY_TX_AMPLITUDE_TUNE		0x20
> >>+#define PHY_TX_SLEWRATE_TUNE		0x22
> >>+#define PHY_VBUSVALID_TH_SEL		0x25
> >>+#define PHY_PULLUP_RES_SEL		0x27
> >>+#define PHY_OTG_FUNC_EN			0x28
> >>+#define PHY_VBUS_DET_EN			0x29
> >>+#define PHY_DISCON_TH_SEL		0x2a
> >>+
> >>+#define MAX_PHYS			3
> >>+
> >>+struct sun4i_usb_phy_data {
> >>+	struct clk *clk;
> >>+	void __iomem *base;
> >>+	struct mutex mutex;
> >>+	int num_phys;
> >>+	u32 disc_thresh;
> >>+	struct sun4i_usb_phy {
> >>+		struct phy *phy;
> >>+		void __iomem *pmu;
> >>+		struct regulator *vbus;
> >>+		struct reset_control *reset;
> >>+		int index;
> >>+	} phys[MAX_PHYS];
> >>+};
> >>+
> >>+#define to_sun4i_usb_phy_data(phy) \
> >>+	container_of((phy), struct sun4i_usb_phy_data, phys[(phy)->index])
> >>+
> >>+static void sun4i_usb_phy_write(struct sun4i_usb_phy *phy, u32 addr, u32 data,
> >>+				int len)
> >>+{
> >>+	struct sun4i_usb_phy_data *phy_data = to_sun4i_usb_phy_data(phy);
> >>+	u32 temp, usbc_bit = BIT(phy->index * 2);
> >>+	int i;
> >>+
> >>+	mutex_lock(&phy_data->mutex);
> >>+
> >>+	for (i = 0; i < len; i++) {
> >>+		temp = readl(phy_data->base + REG_PHYCTL);
> >>+
> >>+		/* clear the address portion */
> >>+		temp &= ~(0xff << 8);
> >>+
> >>+		/* set the address */
> >>+		temp |= ((addr + i) << 8);
> >>+		writel(temp, phy_data->base + REG_PHYCTL);
> >>+
> >>+		/* set the data bit and clear usbc bit*/
> >>+		temp = readb(phy_data->base + REG_PHYCTL);
> >>+		if (data & 0x1)
> >>+			temp |= BIT(7);
> >>+		else
> >>+			temp &= ~BIT(7);
> >>+		temp &= ~usbc_bit;
> >>+		writeb(temp, phy_data->base + REG_PHYCTL);
> >>+
> >>+		/* pulse usbc_bit */
> >>+		temp = readb(phy_data->base + REG_PHYCTL);
> >>+		temp |= usbc_bit;
> >>+		writeb(temp, phy_data->base + REG_PHYCTL);
> >>+
> >>+		temp = readb(phy_data->base + REG_PHYCTL);
> >>+		temp &= ~usbc_bit;
> >>+		writeb(temp, phy_data->base + REG_PHYCTL);
> >>+
> >>+		data >>= 1;
> >>+	}
> >>+	mutex_unlock(&phy_data->mutex);
> >>+}
> >>+
> >>+static void sun4i_usb_phy_passby(struct sun4i_usb_phy *phy, int enable)
> >>+{
> >>+	u32 bits, reg_value;
> >>+
> >>+	if (!phy->pmu)
> >>+		return;
> >>+
> >>+	bits = SUNXI_AHB_ICHR8_EN | SUNXI_AHB_INCR4_BURST_EN |
> >>+		SUNXI_AHB_INCRX_ALIGN_EN | SUNXI_ULPI_BYPASS_EN;
> >>+
> >>+	reg_value = readl(phy->pmu);
> >>+
> >>+	if (enable)
> >>+		reg_value |= bits;
> >>+	else
> >>+		reg_value &= ~bits;
> >>+
> >>+	writel(reg_value, phy->pmu);
> >>+}
> >>+
> >>+static int sun4i_usb_phy_init(struct phy *_phy)
> >>+{
> >>+	struct sun4i_usb_phy *phy = phy_get_drvdata(_phy);
> >>+	struct sun4i_usb_phy_data *data = to_sun4i_usb_phy_data(phy);
> >>+	int ret;
> >>+
> >>+	ret = clk_prepare_enable(data->clk);
> >>+	if (ret)
> >>+		return ret;
> >>+
> >>+	ret = reset_control_deassert(phy->reset);
> >>+	if (ret) {
> >>+		clk_disable_unprepare(data->clk);
> >>+		return ret;
> >>+	}
> >>+
> >>+	/* Adjust PHY's magnitude and rate */
> >>+	sun4i_usb_phy_write(phy, PHY_TX_AMPLITUDE_TUNE, 0x14, 5);
> >>+
> >>+	/* Disconnect threshold adjustment */
> >>+	sun4i_usb_phy_write(phy, PHY_DISCON_TH_SEL, data->disc_thresh, 2);
> >>+
> >>+	sun4i_usb_phy_passby(phy, 1);
> >>+
> >>+	return 0;
> >>+}
> >>+
> >>+static int sun4i_usb_phy_exit(struct phy *_phy)
> >>+{
> >>+	struct sun4i_usb_phy *phy = phy_get_drvdata(_phy);
> >>+	struct sun4i_usb_phy_data *data = to_sun4i_usb_phy_data(phy);
> >>+
> >>+	sun4i_usb_phy_passby(phy, 0);
> >>+	reset_control_assert(phy->reset);
> >>+	clk_disable_unprepare(data->clk);
> >>+
> >>+	return 0;
> >>+}
> >>+
> >>+static int sun4i_usb_phy_power_on(struct phy *_phy)
> >>+{
> >>+	struct sun4i_usb_phy *phy = phy_get_drvdata(_phy);
> >>+	int ret = 0;
> >>+
> >>+	if (phy->vbus)
> >>+		ret = regulator_enable(phy->vbus);
> >>+
> >>+	return ret;
> >>+}
> >>+
> >>+static int sun4i_usb_phy_power_off(struct phy *_phy)
> >>+{
> >>+	struct sun4i_usb_phy *phy = phy_get_drvdata(_phy);
> >>+
> >>+	if (phy->vbus)
> >>+		regulator_disable(phy->vbus);
> >>+
> >>+	return 0;
> >>+}
> >>+
> >>+static struct phy_ops sun4i_usb_phy_ops = {
> >>+	.init		= sun4i_usb_phy_init,
> >>+	.exit		= sun4i_usb_phy_exit,
> >>+	.power_on	= sun4i_usb_phy_power_on,
> >>+	.power_off	= sun4i_usb_phy_power_off,
> >>+	.owner		= THIS_MODULE,
> >>+};
> >>+
> >>+static struct phy *sun4i_usb_phy_xlate(struct device *dev,
> >>+					struct of_phandle_args *args)
> >>+{
> >>+	struct sun4i_usb_phy_data *data = dev_get_drvdata(dev);
> >>+
> >>+	if (WARN_ON(args->args[0] == 0 || args->args[0] >= data->num_phys))
> >>+		return ERR_PTR(-ENODEV);
> >>+
> >>+	return data->phys[args->args[0]].phy;
> >>+}
> >>+
> >>+static int sun4i_usb_phy_probe(struct platform_device *pdev)
> >>+{
> >>+	struct sun4i_usb_phy_data *data;
> >>+	struct device *dev = &pdev->dev;
> >>+	struct device_node *np = dev->of_node;
> >>+	void __iomem *pmu = NULL;
> >>+	struct phy_provider *phy_provider;
> >>+	struct reset_control *reset;
> >>+	struct regulator *vbus;
> >>+	struct phy *phy;
> >>+	char name[16];
> >>+	int i;
> >>+
> >>+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
> >>+	if (!data)
> >>+		return -ENOMEM;
> >>+
> >>+	mutex_init(&data->mutex);
> >>+
> >>+	if (of_device_is_compatible(np, "allwinner,sun5i-a13-usb-phy"))
> >>+		data->num_phys = 2;
> >>+	else
> >>+		data->num_phys = 3;
> >>+
> >>+	if (of_device_is_compatible(np, "allwinner,sun4i-a10-usb-phy"))
> >>+		data->disc_thresh = 3;
> >>+	else
> >>+		data->disc_thresh = 2;
> >
> >I'd still prefer to pass this through the .data field of of_device_id,
> >but it looks much cleaner already :)
> 
> The problem with using the .data field is that I can only store a single
> integer there. To store 2 I need to: define a struct, create an array
> of these structs with initialization. Create an enum for indexing the
> array which must be kept in sync with the initializers manually, store
> either the index, or a direct pointer to the correct array entry into
> the .data field, add code to get the of_device_id from the compatible
> string, and then finally extract the settings from the struct again.
> 
> See IE how this is done in drivers/ata/ahci_platform.c, I've tried
> to come up with a simpler way and failed, for ahci_platform.c the
> struct with per compatible-string data is quite big so it makes some
> sense to use this construction. Here however not so much, this adds a
> whole lot of unnecessary extra code + indirection. I esp. object against
> the indirection as that unnecessarily makes it harder to follow whats
> going on.

Ok, thanks!
Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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