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From:   Christian Eggers <ceggers@arri.de>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC:     Rob Hering <robh@kernel.org>, Rob Herring <robh+dt@kernel.org>,
        "Richard Leitner" <richard.leitner@skidata.com>,
        <devicetree@vger.kernel.org>, <linux-usb@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <ceggers@arri.de>
Subject: [PATCH v3 2/4] usb: misc: Add USB253x/xi Hi-Speed Hub Controller Driver
Date:   Mon, 27 Jul 2020 10:33:31 +0200
Message-ID: <20200727083333.19623-3-ceggers@arri.de>
In-Reply-To: <20200727083333.19623-1-ceggers@arri.de>
References: <20200726084116.GD448215@kroah.com>
 <20200727083333.19623-1-ceggers@arri.de>
MIME-Version: 1.0
Content-Transfer-Encoding: 7BIT
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Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

This patch adds a driver for configuration of the Microchip USB253x/xi
USB 2.0 hub controller series with USB 2.0 upstream connectivity, SMBus
configuration interface and two to four USB 2.0 downstream ports.

Furthermore add myself as a maintainer for this driver.

The datasheet can be found at the manufacturers website, see [1]. All
device-tree exposed configuration features have been tested on a i.MX6
platform with a USB2534i hub.

[1] http://ww1.microchip.com/downloads/en/AppNotes/00001801C.pdf

Signed-off-by: Christian Eggers <ceggers@arri.de>
---
 MAINTAINERS                |   7 +
 drivers/usb/misc/Kconfig   |  10 +
 drivers/usb/misc/Makefile  |   1 +
 drivers/usb/misc/usb253x.c | 834 +++++++++++++++++++++++++++++++++++++
 4 files changed, 852 insertions(+)
 create mode 100644 drivers/usb/misc/usb253x.c

diff --git a/MAINTAINERS b/MAINTAINERS
index d53db30d1365..fe1108ba6ce7 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11356,6 +11356,13 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/usb/usb251xb.txt
 F:	drivers/usb/misc/usb251xb.c
 
+MICROCHIP USB253X DRIVER
+M:	Christian Eggers <ceggers@arri.de>
+L:	linux-usb@vger.kernel.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/usb/usb253x.yaml
+F:	drivers/usb/misc/usb253x.c
+
 MICROCHIP USBA UDC DRIVER
 M:	Cristian Birsan <cristian.birsan@microchip.com>
 L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
diff --git a/drivers/usb/misc/Kconfig b/drivers/usb/misc/Kconfig
index 4e48f8eed168..7a7b854e803a 100644
--- a/drivers/usb/misc/Kconfig
+++ b/drivers/usb/misc/Kconfig
@@ -242,6 +242,16 @@ config USB_HUB_USB251XB
 	  parameters may be set in devicetree or platform data.
 	  Say Y or M here if you need to configure such a device via SMBus.
 
+config USB_HUB_USB253X
+	tristate "USB253X Hub Controller Configuration Driver"
+	depends on I2C
+	select REGMAP
+	help
+	  This option enables support for configuration via I2C bus of the
+	  Microchip USB253x/xi USB 2.0 Hub Controller series.
+	  Configuration parameters may be set in devicetree or platform data.
+	  Say Y or M here if you need to configure such a device via I2C.
+
 config USB_HSIC_USB3503
 	tristate "USB3503 HSIC to USB20 Driver"
 	depends on I2C
diff --git a/drivers/usb/misc/Makefile b/drivers/usb/misc/Makefile
index da39bddb0604..6fd8c53841e4 100644
--- a/drivers/usb/misc/Makefile
+++ b/drivers/usb/misc/Makefile
@@ -25,6 +25,7 @@ obj-$(CONFIG_USB_USS720)		+= uss720.o
 obj-$(CONFIG_USB_SEVSEG)		+= usbsevseg.o
 obj-$(CONFIG_USB_YUREX)			+= yurex.o
 obj-$(CONFIG_USB_HUB_USB251XB)		+= usb251xb.o
+obj-$(CONFIG_USB_HUB_USB253X)		+= usb253x.o
 obj-$(CONFIG_USB_HSIC_USB3503)		+= usb3503.o
 obj-$(CONFIG_USB_HSIC_USB4604)		+= usb4604.o
 obj-$(CONFIG_USB_CHAOSKEY)		+= chaoskey.o
diff --git a/drivers/usb/misc/usb253x.c b/drivers/usb/misc/usb253x.c
new file mode 100644
index 000000000000..ffd72e14c3c3
--- /dev/null
+++ b/drivers/usb/misc/usb253x.c
@@ -0,0 +1,834 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Driver for Microchip USB253x USB 2.0 Hi-Speed Hub Controller
+ * Configuration via I2C.
+ *
+ * Copyright (c) 2020 ARRI Lighting
+ *
+ * This work is based on the USB251xb driver by Richard Leitner.
+ *
+ */
+
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/gpio/driver.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/nls.h>
+#include <linux/of_device.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+
+/* Internal Register Set Addresses acc. to DS00001801C */
+#define USB253X_ADDR_VENDOR_ID                0x3000
+#define USB253X_ADDR_PRODUCT_ID               0x3002
+#define USB253X_ADDR_DEVICE_ID                0x3004
+#define USB253X_ADDR_HUB_CFG                  0x3006
+#define USB253X_HUB_CFG3_PRTMAP_EN            BIT(3)
+#define USB253X_HUB_CFG3_STRING_EN            BIT(0)
+#define USB253X_ADDR_NON_REMOVABLE_DEVICES    0x3009
+#define USB253X_ADDR_PORT_DISABLE_SELF        0x300A
+#define USB253X_ADDR_PORT_DISABLE_BUS         0x300B
+#define USB253X_ADDR_POWER_ON_TIME            0x3010
+#define USB253X_ADDR_LANGUAGE_ID              0x3011
+#define USB253X_ADDR_MANUFACTURER_STRING_LEN  0x3013
+#define USB253X_ADDR_PRODUCT_STRING_LEN       0x3014
+#define USB253X_ADDR_SERIAL_STRING_LEN        0x3015
+#define USB253X_ADDR_STRINGS                  0x3016
+#define USB253X_STRINGS_BUFSIZE              93  /* chars (UTF16) */
+#define USB253X_ADDR_HUB_CTRL_REMAP           0x30FD
+#define USB253X_ADDR_USB2_HUB_CTRL            0x3104
+#define USB253X_USB2_HUB_CTRL_LPM_DISABLE     BIT(1)
+#define USB253X_ADDR_INTERNAL_PORT            0x4130
+#define USB253X_INTERNAL_PORT_PORT_ENUM_DEFAULT        0b00
+#define USB253X_INTERNAL_PORT_PORT_ENUM_ALWAYS_ENABLE  0b01
+#define USB253X_INTERNAL_PORT_PORT_ENUM_ALWAYS_DISABLE 0b10
+
+#define DRIVER_NAME "usb253x"
+
+
+struct usb253x {
+	struct device *dev;
+	struct i2c_client *i2c;
+	struct regulator *vdd;
+	struct regmap *regmap;
+	u8 skip_config;
+	struct gpio_desc *gpio_reset;
+};
+
+#ifdef CONFIG_GPIOLIB
+static int usb253x_check_dev_children(struct device *dev, void *child)
+{
+	if (dev->type == &i2c_adapter_type) {
+		return device_for_each_child(dev, child,
+					     usb253x_check_dev_children);
+	}
+
+	return (dev == child);
+}
+
+static int usb253x_check_gpio_chip(struct usb253x *hub)
+{
+	struct gpio_chip *gc = gpiod_to_chip(hub->gpio_reset);
+	struct i2c_adapter *adap = hub->i2c->adapter;
+	int ret;
+
+	if (!hub->gpio_reset)
+		return 0;
+
+	if (!gc)
+		return -EINVAL;
+
+	ret = usb253x_check_dev_children(&adap->dev, gc->parent);
+	if (ret) {
+		dev_err(hub->dev, "Reset GPIO chip is at the same i2c-bus\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+#else
+static int usb253x_check_gpio_chip(struct usb253x *hub)
+{
+	return 0;
+}
+#endif
+
+static void usb253x_reset(struct usb253x *hub, int state)
+{
+	if (state) {
+		/* During rising edge of reset, there must be no traffic on the i2c bus */
+		i2c_lock_bus(hub->i2c->adapter, I2C_LOCK_SEGMENT);
+		gpiod_set_value_cansleep(hub->gpio_reset, 1);
+		/* Wait for i2c logic to come up (hub seems to require ~210 ms if
+		 * RESET_N pulse was longer than 25 ms)
+		 */
+		msleep(250);
+		i2c_unlock_bus(hub->i2c->adapter, I2C_LOCK_SEGMENT);
+	} else {
+		gpiod_set_value_cansleep(hub->gpio_reset, 0);
+		/* minimum reset pulse width from data sheet is 5 us */
+		usleep_range(5, 10);
+	}
+}
+
+static void usb253x_get_ports_field(struct usb253x *hub,
+				    const char *prop_name, u8 port_cnt,
+				    u8 *fld)
+{
+	struct device *dev = hub->dev;
+	struct property *prop;
+	const __be32 *p;
+	u32 port;
+
+	of_property_for_each_u32(dev->of_node, prop_name, prop, p, port) {
+		if ((port >= 1) && (port <= port_cnt))
+			*fld |= BIT(port);
+		else
+			dev_warn(dev, "port %u doesn't exist\n", port);
+	}
+}
+
+static int usb253x_connect(struct usb253x *hub)
+{
+	struct device *dev = hub->dev;
+	struct device_node *np = dev->of_node;
+	int err;
+	char attach_buffer[3];
+
+	usb253x_reset(hub, 1);
+
+	if (hub->skip_config) {
+		dev_info(dev, "Skip hub configuration, only attach.\n");
+	} else {
+		u16 vendor_id, product_id, device_id, lang_id;
+		u8 hub_cfg[3];
+		u32 property_u32;
+		char const *manufacturer;
+		char const *product;
+		char const *serial;
+		u8 non_rem_dev = 0;
+		u8 port_disable_sp = 0;
+		u8 port_disable_bp = 0;
+		wchar_t strings[USB253X_STRINGS_BUFSIZE];
+		int strings_used = 0;
+		u32 hub_controller_port = 0;
+
+		memset(strings, 0, sizeof(strings));
+
+		if (!of_property_read_u16_array(np, "vendor-id", &vendor_id, 1)) {
+			char buffer[] = { vendor_id >> 8, vendor_id };
+
+			err = regmap_bulk_write(hub->regmap, USB253X_ADDR_VENDOR_ID,
+					buffer, ARRAY_SIZE(buffer));
+			if (err) {
+				dev_err(dev, "Setting vendor id failed: %d\n", err);
+				return err;
+			}
+		}
+
+		if (!of_property_read_u16_array(np, "product-id", &product_id, 1)) {
+			char buffer[] = { product_id >> 8, product_id };
+
+			err = regmap_bulk_write(hub->regmap, USB253X_ADDR_PRODUCT_ID,
+					buffer, ARRAY_SIZE(buffer));
+			if (err) {
+				dev_err(dev, "Setting product id failed: %d\n", err);
+				return err;
+			}
+		}
+
+		if (!of_property_read_u16_array(np, "device-id", &device_id, 1)) {
+			char buffer[] = { device_id >> 8, device_id };
+
+			err = regmap_bulk_write(hub->regmap, USB253X_ADDR_DEVICE_ID,
+					buffer, ARRAY_SIZE(buffer));
+			if (err) {
+				dev_err(dev, "Setting device id failed: %d\n", err);
+				return err;
+			}
+		}
+
+		err = regmap_bulk_read(hub->regmap, USB253X_ADDR_HUB_CFG,
+				hub_cfg, ARRAY_SIZE(hub_cfg));
+		if (err) {
+			dev_err(dev, "Reading hub cfg failed: %d\n", err);
+			return err;
+		}
+
+		if (of_get_property(np, "self-powered", NULL)) {
+			hub_cfg[0] |= BIT(7);
+
+			/* Configure Over-Current sens when self-powered */
+			hub_cfg[0] &= ~BIT(2);
+			if (of_get_property(np, "ganged-sensing", NULL))
+				hub_cfg[0] &= ~BIT(1);
+			else if (of_get_property(np, "individual-sensing", NULL))
+				hub_cfg[0] |= BIT(1);
+		} else if (of_get_property(np, "bus-powered", NULL)) {
+			hub_cfg[0] &= ~BIT(7);
+
+			/* Disable Over-Current sense when bus-powered */
+			hub_cfg[0] |= BIT(2);
+		}
+
+		if (of_get_property(np, "disable-hi-speed", NULL))
+			hub_cfg[0] |= BIT(5);
+
+		if (of_get_property(np, "multi-tt", NULL))
+			hub_cfg[0] |= BIT(4);
+		else if (of_get_property(np, "single-tt", NULL))
+			hub_cfg[0] &= ~BIT(4);
+
+		if (of_get_property(np, "disable-eop", NULL))
+			hub_cfg[0] |= BIT(3);
+
+		if (of_get_property(np, "individual-port-switching", NULL))
+			hub_cfg[0] |= BIT(0);
+		else if (of_get_property(np, "ganged-port-switching", NULL))
+			hub_cfg[0] &= ~BIT(0);
+
+		if (of_get_property(np, "dynamic-power-switching", NULL))
+			hub_cfg[1] |= BIT(7);
+
+		if (!of_property_read_u32(np, "oc-delay-us", &property_u32)) {
+			if (property_u32 == 100) {
+				/* 100 us*/
+				hub_cfg[1] &= ~BIT(5);
+				hub_cfg[1] &= ~BIT(4);
+			} else if (property_u32 == 4000) {
+				/* 4 ms */
+				hub_cfg[1] &= ~BIT(5);
+				hub_cfg[1] |= BIT(4);
+			} else if (property_u32 == 16000) {
+				/* 16 ms */
+				hub_cfg[1] |= BIT(5);
+				hub_cfg[1] |= BIT(4);
+			} else {
+				/* 8 ms (DEFAULT) */
+				hub_cfg[1] |= BIT(5);
+				hub_cfg[1] &= ~BIT(4);
+			}
+		}
+
+		if (of_get_property(np, "compound-device", NULL))
+			hub_cfg[1] |= BIT(3);
+
+		if (of_get_property(np, "port-mapping-mode", NULL))
+			hub_cfg[2] |= USB253X_HUB_CFG3_PRTMAP_EN;
+
+		/* hub controller will only work when port mapping is enabled and
+		 * controller port is mapped
+		 */
+		if (!of_property_read_u32(np, "hub-controller-port",
+				&hub_controller_port))
+			hub_cfg[2] |= USB253X_HUB_CFG3_PRTMAP_EN;
+
+		/* port mapping requires that Link Power Management is disabled */
+		if (hub_cfg[2] & USB253X_HUB_CFG3_PRTMAP_EN) {
+			unsigned int usb2_hub_ctrl;
+
+			/* Disable Link Power Management */
+			err = regmap_read(hub->regmap, USB253X_ADDR_USB2_HUB_CTRL,
+					&usb2_hub_ctrl);
+			if (err) {
+				dev_err(dev, "Reading USB2 Hub Control failed: %d\n", err);
+				return err;
+			}
+
+			usb2_hub_ctrl |= USB253X_USB2_HUB_CTRL_LPM_DISABLE;
+
+			err = regmap_write(hub->regmap, USB253X_ADDR_USB2_HUB_CTRL,
+					usb2_hub_ctrl);
+			if (err) {
+				dev_err(dev, "Writing USB2 Hub Control failed: %d\n", err);
+				return err;
+			}
+		}
+
+		manufacturer = of_get_property(np, "manufacturer", NULL);
+		product = of_get_property(np, "product", NULL);
+		serial = of_get_property(np, "serial", NULL);
+
+		if (manufacturer || product || serial)
+			hub_cfg[2] |= USB253X_HUB_CFG3_STRING_EN;
+
+		err = regmap_bulk_write(hub->regmap, USB253X_ADDR_HUB_CFG,
+				hub_cfg, ARRAY_SIZE(hub_cfg));
+		if (err) {
+			dev_err(dev, "Setting hub cfg failed: %d\n", err);
+			return err;
+		}
+
+		usb253x_get_ports_field(hub, "non-removable-ports", 4, &non_rem_dev);
+		err = regmap_write(hub->regmap, USB253X_ADDR_NON_REMOVABLE_DEVICES,
+				non_rem_dev);
+		if (err) {
+			dev_err(dev, "Setting non removable devices failed: %d\n", err);
+			return err;
+		}
+
+		usb253x_get_ports_field(hub, "sp-disabled-ports", 4, &port_disable_sp);
+		err = regmap_write(hub->regmap, USB253X_ADDR_PORT_DISABLE_SELF,
+				port_disable_sp);
+		if (err) {
+			dev_err(dev, "Setting port disable self powered failed: %d\n", err);
+			return err;
+		}
+
+		usb253x_get_ports_field(hub, "bp-disabled-ports", 4, &port_disable_bp);
+		err = regmap_write(hub->regmap, USB253X_ADDR_PORT_DISABLE_BUS,
+				port_disable_bp);
+		if (err) {
+			dev_err(dev, "Setting port disable powered powered failed: %d\n", err);
+			return err;
+		}
+
+		if (!of_property_read_u32(np, "power-on-time-ms", &property_u32)) {
+			u8 power_on_time = min_t(u8, property_u32 / 2, 255);
+
+			err = regmap_write(hub->regmap, USB253X_ADDR_POWER_ON_TIME,
+					power_on_time);
+			if (err) {
+				dev_err(dev, "Setting port disable powered powered failed: %d\n",
+						err);
+				return err;
+			}
+		}
+
+		if (!of_property_read_u16_array(np, "language-id", &lang_id, 1)) {
+			char buffer[] = { lang_id >> 8, lang_id };
+
+			err = regmap_bulk_write(hub->regmap, USB253X_ADDR_LANGUAGE_ID,
+					buffer, ARRAY_SIZE(buffer));
+			if (err) {
+				dev_err(dev, "Setting language id failed: %d\n", err);
+				return err;
+			}
+		}
+
+		if (manufacturer) {
+			u8 manufacturer_len = utf8s_to_utf16s(manufacturer, strlen(manufacturer),
+					UTF16_LITTLE_ENDIAN,
+					&strings[strings_used],
+					USB253X_STRINGS_BUFSIZE - strings_used);
+
+			err = regmap_write(hub->regmap, USB253X_ADDR_MANUFACTURER_STRING_LEN,
+					manufacturer_len);
+			if (err) {
+				dev_err(dev, "Setting manufacturer string length failed: %d\n",
+						err);
+				return err;
+			}
+
+			strings_used += manufacturer_len;
+		}
+
+		if (product) {
+			u8 product_len = utf8s_to_utf16s(product, strlen(product),
+					UTF16_LITTLE_ENDIAN,
+					&strings[strings_used],
+					USB253X_STRINGS_BUFSIZE - strings_used);
+
+			err = regmap_write(hub->regmap, USB253X_ADDR_PRODUCT_STRING_LEN,
+					product_len);
+			if (err) {
+				dev_err(dev, "Setting product string length failed: %d\n", err);
+				return err;
+			}
+
+			strings_used += product_len;
+		}
+
+		if (serial) {
+			u8 serial_len = utf8s_to_utf16s(serial, strlen(serial),
+					UTF16_LITTLE_ENDIAN,
+					&strings[strings_used],
+					USB253X_STRINGS_BUFSIZE - strings_used);
+
+			err = regmap_write(hub->regmap, USB253X_ADDR_SERIAL_STRING_LEN,
+					serial_len);
+			if (err) {
+				dev_err(dev, "Setting serial string length failed: %d\n", err);
+				return err;
+			}
+
+			strings_used += serial_len;
+		}
+
+		err = regmap_bulk_write(hub->regmap, USB253X_ADDR_STRINGS,
+				strings, sizeof(strings));
+		if (err) {
+			dev_err(dev, "Setting strings failed: %d\n", err);
+			return err;
+		}
+
+		if (hub_controller_port != 0) {
+			/* Writes to this register are disabled unless PRTMAP_EN bit in
+			 * HUB_CFG_3 is set.
+			 */
+			err = regmap_write(hub->regmap, USB253X_ADDR_HUB_CTRL_REMAP,
+					hub_controller_port);
+			if (err) {
+				dev_err(dev, "Setting hub controller remap failed: %d\n", err);
+				return err;
+			}
+
+			err = regmap_write(hub->regmap, USB253X_ADDR_INTERNAL_PORT,
+					USB253X_INTERNAL_PORT_PORT_ENUM_ALWAYS_ENABLE);
+			if (err) {
+				dev_err(dev, "Setting internal port failed: %d\n", err);
+				return err;
+			}
+		}
+	}
+
+#ifdef DEBUG
+	{
+		char *buffer = kzalloc(0x5000, GFP_KERNEL);
+
+		err = regmap_bulk_read(hub->regmap, 0, buffer, 0x5000);
+		print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, buffer, 0x5000);
+		kfree(buffer);
+	}
+#endif
+
+	/*
+	 *  attach
+	 */
+	attach_buffer[0] = 0xAA;   /* USB attach (high byte) */
+	attach_buffer[1] = 0x55;   /* USB attach (low byte) */
+	attach_buffer[2] = 0x00;   /* terminator */
+
+	err = i2c_master_send(hub->i2c, attach_buffer, 3);
+	if (err != 3) {
+		dev_err(dev, "attaching hub failed: %d\n", err);
+		return err;
+	}
+
+	dev_info(dev, "Hub configuration was successful.\n");
+	return 0;
+
+}
+
+#ifdef CONFIG_OF
+static int usb253x_get_ofdata(struct usb253x *hub)
+{
+	struct device *dev = hub->dev;
+	struct device_node *np = dev->of_node;
+
+	if (!np) {
+		dev_err(dev, "failed to get ofdata\n");
+		return -ENODEV;
+	}
+
+	if (of_get_property(np, "skip-config", NULL))
+		hub->skip_config = 1;
+	else
+		hub->skip_config = 0;
+
+	hub->gpio_reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
+	if (IS_ERR(hub->gpio_reset))
+		return PTR_ERR(hub->gpio_reset);
+
+	return 0;
+}
+
+static const struct of_device_id usb253x_of_match[] = {
+	{ .compatible = "microchip,usb2532",  },
+	{ .compatible = "microchip,usb2532i", },
+	{ .compatible = "microchip,usb2533",  },
+	{ .compatible = "microchip,usb2533i", },
+	{ .compatible = "microchip,usb2534",  },
+	{ .compatible = "microchip,usb2534i", },
+	{ .compatible = "microchip,usb3613",  },
+	{ .compatible = "microchip,usb3613i", },
+	{ .compatible = "microchip,usb3813",  },
+	{ .compatible = "microchip,usb3813i", },
+	{ .compatible = "microchip,usb4604",  },
+	{ .compatible = "microchip,usb4604i", },
+	{ .compatible = "microchip,usb4624",  },
+	{ .compatible = "microchip,usb4624i", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, usb253x_of_match);
+#else /* CONFIG_OF */
+static int usb253x_get_ofdata(struct usb253x *hub)
+{
+	return 0;
+}
+#endif /* CONFIG_OF */
+
+static void usb253x_regulator_disable_action(void *data)
+{
+	struct usb253x *hub = data;
+
+	regulator_disable(hub->vdd);
+}
+
+static int usb253x_probe(struct usb253x *hub)
+{
+	struct device *dev = hub->dev;
+	struct device_node *np = dev->of_node;
+	int err;
+
+	if (np) {
+		err = usb253x_get_ofdata(hub);
+		if (err) {
+			dev_err(dev, "failed to get ofdata: %d\n", err);
+			return err;
+		}
+	}
+
+	/*
+	 * usb253x SMBus-slave SCL lane is muxed with CFG_SEL0 pin. So if anyone
+	 * tries to work with the bus at the moment the hub reset is released,
+	 * it may cause an invalid config being latched by usb253x. Particularly
+	 * one of the config modes makes the hub loading a default registers
+	 * value without SMBus-slave interface activation. If the hub
+	 * accidentally gets this mode, this will cause the driver SMBus-
+	 * functions failure. Normally we could just lock the SMBus-segment the
+	 * hub i2c-interface resides for the device-specific reset timing. But
+	 * the GPIO controller, which is used to handle the hub reset, might be
+	 * placed at the same i2c-bus segment. In this case an error should be
+	 * returned since we can't safely use the GPIO controller to clear the
+	 * reset state (it may affect the hub configuration) and we can't lock
+	 * the i2c-bus segment (it will cause a deadlock).
+	 */
+	err = usb253x_check_gpio_chip(hub);
+	if (err)
+		return err;
+
+	hub->vdd = devm_regulator_get(dev, "vdd");
+	if (IS_ERR(hub->vdd))
+		return PTR_ERR(hub->vdd);
+
+	err = regulator_enable(hub->vdd);
+	if (err)
+		return err;
+
+	err = devm_add_action_or_reset(dev,
+				       usb253x_regulator_disable_action, hub);
+	if (err)
+		return err;
+
+	err = usb253x_connect(hub);
+	if (err) {
+		dev_err(dev, "Failed to connect hub (%d)\n", err);
+		return err;
+	}
+
+	dev_info(dev, "Hub probed successfully\n");
+
+	return 0;
+}
+
+static int usb253x_i2c_gather_write(void *context,
+		const void *reg, size_t reg_len,
+		const void *val, size_t val_len)
+{
+	struct i2c_client *i2c = (struct i2c_client *)context;
+	size_t frame_len = val_len + 7;
+	char *buffer;
+	int err;
+
+	if (WARN_ON(reg_len != 2))
+		return -EINVAL;
+
+	buffer = kmalloc(frame_len, GFP_KERNEL);
+	if (!buffer)
+		return -ENOMEM;
+
+	buffer[0] = 0x00;                 /* Memory address (high byte) */
+	buffer[1] = 0x00;                 /* Memory address (low byte) */
+	buffer[2] = val_len + 4;          /* Number of bytes to write to memory */
+	buffer[3] = 0x00;                 /* Register Write */
+	buffer[4] = val_len;              /* Write val_len data bytes */
+	buffer[5] = *((const char *)reg + 0);   /* Register address (high byte) */
+	buffer[6] = *((const char *)reg + 1);   /* Register address (low byte) */
+	memcpy(&buffer[7], val, val_len);
+
+	err = i2c_master_send(i2c, buffer, frame_len);
+	if (err != (int)frame_len) {
+		dev_err(&i2c->dev, "Writing to hub memory failed: %d\n", err);
+		goto error_kfree;
+	}
+
+	buffer[0] = 0x99;   /* Command (high byte) */
+	buffer[1] = 0x37;   /* Command (low byte) */
+	buffer[2] = 0x00;   /* Termination */
+	frame_len = 3;
+
+	err = i2c_master_send(i2c, buffer, frame_len);
+	if (err != (int)frame_len) {
+		dev_err(&i2c->dev, "Accessing configuration data failed: %d\n", err);
+		goto error_kfree;
+	}
+
+	err = 0;
+
+error_kfree:
+	kfree(buffer);
+	return err;
+}
+
+/* regmap puts address into data[0] and data[1]; value is in data[2] */
+static int usb253x_i2c_write(void *context, const void *data, size_t count)
+{
+	if (WARN_ON(count != 3))
+		return -EINVAL;
+
+	return usb253x_i2c_gather_write(context, data, 2, data + 2, 1);
+}
+
+static int usb253x_i2c_read(void *context, const void *reg_buf, size_t reg_size,
+		void *val_buf, size_t val_size)
+{
+	struct i2c_client *i2c = (struct i2c_client *)context;
+	char *tx, *rx;
+	int err;
+
+	if (WARN_ON(reg_size != 2)) {
+		err =  -EINVAL;
+		goto error_return;
+	}
+
+	tx = kmalloc(7, GFP_KERNEL);
+	if (!tx) {
+		err = -ENOMEM;
+		goto error_return;
+	}
+
+	rx = kmalloc(1 + val_size, GFP_KERNEL);
+	if (!rx) {
+		err = -ENOMEM;
+		goto error_free_tx;
+	}
+
+	tx[0] = 0x00;                 /* Memory address (high byte) */
+	tx[1] = 0x00;                 /* Memory address (low byte) */
+	tx[2] = 4;                    /* Number of bytes to write to memory */
+	tx[3] = 0x01;                 /* Register Read */
+	tx[4] = val_size;             /* Read val_size data bytes */
+	tx[5] = *((const char *)reg_buf + 0);   /* Register address (high byte) */
+	tx[6] = *((const char *)reg_buf + 1);   /* Register address (low byte) */
+
+	err = i2c_master_send(i2c, tx, 7);
+	if (err != 7) {
+		dev_err(&i2c->dev, "Writing to hub memory failed: %d\n", err);
+		goto error_free_rx;
+	}
+
+	tx[0] = 0x99;   /* Command (high byte) */
+	tx[1] = 0x37;   /* Command (low byte) */
+	tx[2] = 0x00;   /* Termination */
+
+	err = i2c_master_send(i2c, tx, 3);
+	if (err != 3) {
+		dev_err(&i2c->dev, "Accessing configuration data failed: %d\n", err);
+		goto error_free_rx;
+	}
+
+	/* Read from hub memory address 4 (according to application note) */
+	tx[0] = 0x00;    /* Memory address (high byte) */
+	tx[1] = 0x04;    /* Memory address (low byte) */
+
+	{
+		struct i2c_msg msgs[] = {
+			{
+				.addr = i2c->addr, .flags = 0,
+				.len  =         2, .buf = tx
+			},
+			{
+				.addr = i2c->addr, .flags = I2C_M_RD,
+				.len = 1 + val_size, .buf = rx
+			},
+		};
+
+		err = i2c_transfer(i2c->adapter, msgs, ARRAY_SIZE(msgs));
+		if (err < 0) {
+			dev_err(&i2c->dev, "Reading from hub memory failed: %d\n", err);
+			goto error_free_rx;
+		}
+	}
+
+	WARN_ON(rx[0] < val_size);
+
+	memcpy(val_buf, &rx[1], val_size);
+
+	err = 0;
+
+error_free_rx:
+	kfree(rx);
+error_free_tx:
+	kfree(tx);
+error_return:
+	return err;
+}
+
+/*
+ * The reason we need this custom regmap_bus instead of using regmap_init_i2c()
+ * is that accesses to the USB253x configuration memory have to be wrapped into
+ * a special protocol.
+ */
+static const struct regmap_bus usb253x_i2c_regmap = {
+	.write         = usb253x_i2c_write,
+	.gather_write  = usb253x_i2c_gather_write,
+	.read          = usb253x_i2c_read,
+	.max_raw_read  = 128,
+	.max_raw_write = 128,
+};
+
+/* Avoid reading bigger dead ranges inside hubs memory.  Same table for
+ * read and write.
+ */
+static const struct regmap_range usb253x_regmap_yes_ranges[] = {
+	{ .range_min = 0x0800, .range_max = 0x09ff },
+	{ .range_min = 0x3000, .range_max = 0x31ff },
+	{ .range_min = 0x3C00, .range_max = 0x3cff },
+	{ .range_min = 0x4100, .range_max = 0x42ff },
+	{ .range_min = 0x6000, .range_max = 0x72ff },
+};
+
+static const struct regmap_access_table usb253x_regmap_access_table = {
+	.yes_ranges   = usb253x_regmap_yes_ranges,
+	.n_yes_ranges = ARRAY_SIZE(usb253x_regmap_yes_ranges),
+};
+
+static int usb253x_i2c_probe(struct i2c_client *i2c,
+			      const struct i2c_device_id *id __always_unused)
+{
+	struct usb253x *hub;
+	struct regmap_config regmap_cfg = {
+		.name            = "usb253x_config_mem",
+		.reg_bits        = 16,
+		.val_bits        = 8,
+		.max_register    = 0x7fff,
+		.wr_table        = &usb253x_regmap_access_table,
+		.rd_table        = &usb253x_regmap_access_table,
+		.can_multi_write = 1,
+	};
+
+	hub = devm_kzalloc(&i2c->dev, sizeof(struct usb253x), GFP_KERNEL);
+	if (!hub)
+		return -ENOMEM;
+
+	i2c_set_clientdata(i2c, hub);
+	hub->dev = &i2c->dev;
+	hub->i2c = i2c;
+	hub->regmap = devm_regmap_init(&i2c->dev, &usb253x_i2c_regmap, i2c,
+			&regmap_cfg);
+	if (IS_ERR(hub->regmap))
+		return PTR_ERR(hub->regmap);
+
+	return usb253x_probe(hub);
+}
+
+static int usb253x_i2c_remove(struct i2c_client *i2c)
+{
+	struct usb253x *hub = i2c_get_clientdata(i2c);
+
+	usb253x_reset(hub, 0);
+
+	return 0;
+};
+
+static int __maybe_unused usb253x_suspend(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct usb253x *hub = i2c_get_clientdata(client);
+
+	return regulator_disable(hub->vdd);
+}
+
+static int __maybe_unused usb253x_resume(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct usb253x *hub = i2c_get_clientdata(client);
+	int err;
+
+	err = regulator_enable(hub->vdd);
+	if (err)
+		return err;
+
+	return usb253x_connect(hub);
+}
+
+static SIMPLE_DEV_PM_OPS(usb253x_pm_ops, usb253x_suspend, usb253x_resume);
+
+static const struct i2c_device_id usb253x_id[] = {
+	{ "usb2532", 0 },
+	{ "usb2532i", 0 },
+	{ "usb2533", 0 },
+	{ "usb2533i", 0 },
+	{ "usb2534", 0 },
+	{ "usb2534i", 0 },
+	{ "usb3613", 0 },
+	{ "usb3613i", 0 },
+	{ "usb3813", 0 },
+	{ "usb3813i", 0 },
+	{ "usb4604", 0 },
+	{ "usb4604i", 0 },
+	{ "usb4624", 0 },
+	{ "usb4624i", 0 },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(i2c, usb253x_id);
+
+static struct i2c_driver usb253x_i2c_driver = {
+	.driver = {
+		.name = DRIVER_NAME,
+		.of_match_table = of_match_ptr(usb253x_of_match),
+		.pm = &usb253x_pm_ops,
+	},
+	.probe    = usb253x_i2c_probe,
+	.remove   = usb253x_i2c_remove,
+	.id_table = usb253x_id,
+};
+
+module_i2c_driver(usb253x_i2c_driver);
+
+MODULE_AUTHOR("Christian Eggers <ceggers@arri.de>");
+MODULE_DESCRIPTION("USB253x/xi USB 2.0 Hub Controller Driver");
+MODULE_LICENSE("GPL");
-- 
Christian Eggers
Embedded software developer

Arnold & Richter Cine Technik GmbH & Co. Betriebs KG
Sitz: Muenchen - Registergericht: Amtsgericht Muenchen - Handelsregisternummer: HRA 57918
Persoenlich haftender Gesellschafter: Arnold & Richter Cine Technik GmbH
Sitz: Muenchen - Registergericht: Amtsgericht Muenchen - Handelsregisternummer: HRB 54477
Geschaeftsfuehrer: Dr. Michael Neuhaeuser; Stephan Schenk; Walter Trauninger; Markus Zeiler