[PATCH v3 2/2] usb: misc: usb5807: Add driver

[Mike Looijmans]

The USB5807 is a 7-port USB 3.1 hub that can be configured by I2C.
This drivers resets the chip, optionally allows D+/D- lines to be
swapped in the devicetree config, and then sends an ATTACH command to
put the device in operational mode.

Signed-off-by: Mike Looijmans <mike.looijmans@xxxxxxxx>

---

(no changes since v2)

Changes in v2:
Add regulator support for vddXX supplies

 drivers/usb/misc/Kconfig   |   9 ++
 drivers/usb/misc/Makefile  |   1 +
 drivers/usb/misc/usb5807.c | 184 +++++++++++++++++++++++++++++++++++++
 3 files changed, 194 insertions(+)
 create mode 100644 drivers/usb/misc/usb5807.c

diff --git a/drivers/usb/misc/Kconfig b/drivers/usb/misc/Kconfig
index 99b15b77dfd5..6659e917ea26 100644
--- a/drivers/usb/misc/Kconfig
+++ b/drivers/usb/misc/Kconfig
@@ -251,6 +251,15 @@ config USB_EZUSB_FX2
 	  Say Y here if you need EZUSB device support.
 	  (Cypress FX/FX2/FX2LP microcontrollers)
 
+config USB_HUB_USB5807
+	tristate "USB5807 Hub Controller Configuration Driver"
+	depends on I2C
+	help
+	  This option enables support for configuration via SMBus of the
+	  Microchip USB5807 USB 3.1 Hub Controller. Configuration parameters may
+	  be set in devicetree.
+	  Say Y or M here if you need to configure such a device via SMBus.
+
 config USB_HUB_USB251XB
 	tristate "USB251XB Hub Controller Configuration Driver"
 	depends on I2C
diff --git a/drivers/usb/misc/Makefile b/drivers/usb/misc/Makefile
index 1992cc284d8a..e827ed251fa5 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-$(CONFIG_USB_HUB_USB5807)		+= usb5807.o
 obj-$(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/usb5807.c b/drivers/usb/misc/usb5807.c
new file mode 100644
index 000000000000..c617f3371fa1
--- /dev/null
+++ b/drivers/usb/misc/usb5807.c
@@ -0,0 +1,184 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Driver for Microchip USB5807 USB 3.1 Hub
+ * Configuration via SMBus.
+ *
+ * Copyright (c) 2023 Topic Embedded Products
+ */
+
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/regulator/consumer.h>
+
+#define USB5807_CMD_ATTACH 0xAA55
+#define USB5807_CMD_CONFIG 0x9937
+
+#define USB5807_REG_LANE_SWAP 0x30FA
+
+#define USB5807_NUM_PORTS 7
+
+
+static int usb5807_write(struct i2c_client *i2c, void *buf, u8 len)
+{
+	int ret;
+	struct i2c_msg msg = {
+		.addr	= i2c->addr,
+		.flags  = 0x0,
+		.len	= len,
+		.buf	= buf,
+	};
+
+	ret = i2c_transfer(i2c->adapter, &msg, 1);
+	return ret < 0 ? ret : 0;
+}
+
+/*
+ * Send a command sequence, which is an I2C write transaction, with the command
+ * word in big endian and a terminating "0" byte.
+ */
+static int usb5807_command(struct i2c_client *i2c, u16 cmd)
+{
+	u8 buf[3] = {cmd >> 8, cmd & 0xff, 0};
+
+	return usb5807_write(i2c, buf, sizeof(buf));
+}
+
+static int usb5807_prepare_reg_u8(struct i2c_client *i2c, u16 reg, u8 value)
+{
+	u8 buf[] = {
+		0x00,
+		0x00,		/* Memory offset */
+		1 + 4,		/* Transaction size */
+		0x00,		/* 0 = Register write operation */
+		1,		/* Size of register data */
+		(reg >> 8) & 0xff,
+		reg & 0xff,	/* Register offset */
+		value,		/* Register data */
+		0		/* Terminating zero */
+	};
+
+	return usb5807_write(i2c, buf, sizeof(buf));
+}
+
+/*
+ * Write an 8-bit register. First we must write the "set register" operation to
+ * the chip's internal memory at offset 0, then issue a command to execute said
+ * operation.
+ */
+static int usb5807_write_reg_u8(struct i2c_client *i2c, u16 reg, u8 value)
+{
+	int ret;
+
+	ret = usb5807_prepare_reg_u8(i2c, reg, value);
+	if (ret)
+		return ret;
+
+	return usb5807_command(i2c, USB5807_CMD_CONFIG);
+}
+
+/* Decode array of port numbers property into bit mask */
+static u8 usb5807_get_ports_field(struct device *dev, const char *prop_name)
+{
+	struct property *prop;
+	const __be32 *p;
+	u32 port;
+	u8 result = 0;
+
+	of_property_for_each_u32(dev->of_node, prop_name, prop, p, port) {
+		if (port < USB5807_NUM_PORTS)
+			result |= BIT(port);
+		else
+			dev_warn(dev, "%s: port %u doesn't exist\n", prop_name,
+				 port);
+	}
+	return result;
+}
+
+static int usb5807_i2c_probe(struct i2c_client *i2c)
+{
+	struct gpio_desc *reset_gpio;
+	int ret;
+	u8 val;
+
+	/* Reset the chip to bring it into configuration mode */
+	reset_gpio = devm_gpiod_get_optional(&i2c->dev, "reset",
+					     GPIOD_OUT_HIGH);
+	if (IS_ERR(reset_gpio)) {
+		return dev_err_probe(&i2c->dev, PTR_ERR(reset_gpio),
+				     "Failed to request reset GPIO\n");
+	}
+
+	/* Enable power supplies while chip is held in reset */
+	ret = devm_regulator_get_enable(&i2c->dev, "vdd12");
+	if (ret)
+		return ret;
+
+	ret = devm_regulator_get_enable(&i2c->dev, "vdd33");
+	if (ret)
+		return ret;
+
+	/* Reset timing: Assert for >= 5 us */
+	usleep_range(5, 10);
+
+	/* Lock the bus for >= 1ms while the hub reads the I2C strapping */
+	i2c_lock_bus(i2c->adapter, I2C_LOCK_SEGMENT);
+
+	gpiod_set_value_cansleep(reset_gpio, 0);
+	usleep_range(1000, 2000);
+
+	i2c_unlock_bus(i2c->adapter, I2C_LOCK_SEGMENT);
+
+	/* The hub device needs additional time to boot up */
+	msleep(20);
+
+	val = usb5807_get_ports_field(&i2c->dev, "swap-dx-lanes");
+	if (val) {
+		ret = usb5807_write_reg_u8(i2c, USB5807_REG_LANE_SWAP, val);
+		if (ret < 0)
+			dev_err(&i2c->dev, "Failed writing config: %d\n", ret);
+	}
+
+	/*
+	 * Send the "Attach" command which makes the device disappear from the
+	 * I2C bus and starts USB enumeration.
+	 */
+	ret = usb5807_command(i2c, USB5807_CMD_ATTACH);
+	if (ret) {
+		dev_err(&i2c->dev, "Failed sending ATTACH command: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id usb5807_of_match[] = {
+	{ .compatible = "microchip,usb5807" },
+	{ } /* sentinel */
+};
+MODULE_DEVICE_TABLE(of, usb5807_of_match);
+
+static const struct i2c_device_id usb5807_id[] = {
+	{ "usb5807", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(i2c, usb5807_id);
+
+static struct i2c_driver usb5807_i2c_driver = {
+	.driver = {
+		.name = "usb5807",
+		.of_match_table = of_match_ptr(usb5807_of_match),
+	},
+	.probe_new = usb5807_i2c_probe,
+	.id_table = usb5807_id,
+};
+
+module_i2c_driver(usb5807_i2c_driver);
+
+MODULE_AUTHOR("Mike Looijmans <mike.looijmans@xxxxxxxx>");
+MODULE_DESCRIPTION("USB5807 USB 3.1 Hub Controller Driver");
+MODULE_LICENSE("GPL");
-- 
2.17.1


Met vriendelijke groet / kind regards,

Mike Looijmans
System Expert


TOPIC Embedded Products B.V.
Materiaalweg 4, 5681 RJ Best
The Netherlands

T: +31 (0) 499 33 69 69
E: mike.looijmans@xxxxxxxxxxxxxxxxx
W: www.topic.nl

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