USB: serial: f81232: add control driver for F81534A

The Fintek F81534A series contains 1 HUB, 1 GPIO device and n UARTs. The
UARTs are disabled by default and need to be enabled by the GPIO device
(2c42:16F8).

When F81534A plug to host, we can only see 1 HUB and 1 GPIO device and
we write 0x8fff to GPIO device register F81534A_CTRL_CMD_ENABLE_PORT
(116h) to enable all available serial ports.
Signed-off-by: Ji-Ze Hong (Peter Hong) <hpeter+linux_kernel@gmail.com>
[johan: reword commit message and an error message slightly]
Signed-off-by: Johan Hovold <johan@kernel.org>

drivers/usb/serial/f81232.c

@@ -36,6 +36,9 @@
 	{ USB_DEVICE(0x2c42, 0x1635) },	/* 8 port UART device */ \
 	{ USB_DEVICE(0x2c42, 0x1636) }	/* 12 port UART device */
 
+#define F81534A_CTRL_ID		\
+	{ USB_DEVICE(0x2c42, 0x16f8) }	/* Global control device */
+
 static const struct usb_device_id f81232_id_table[] = {
 	F81232_ID,
 	{ }					/* Terminating entry */
@@ -46,9 +49,15 @@ static const struct usb_device_id f81534a_id_table[] = {
 	{ }					/* Terminating entry */
 };
 
+static const struct usb_device_id f81534a_ctrl_id_table[] = {
+	F81534A_CTRL_ID,
+	{ }					/* Terminating entry */
+};
+
 static const struct usb_device_id combined_id_table[] = {
 	F81232_ID,
 	F81534A_SERIES_ID,
+	F81534A_CTRL_ID,
 	{ }					/* Terminating entry */
 };
 MODULE_DEVICE_TABLE(usb, combined_id_table);
@@ -61,6 +70,7 @@ MODULE_DEVICE_TABLE(usb, combined_id_table);
 #define F81232_REGISTER_REQUEST		0xa0
 #define F81232_GET_REGISTER		0xc0
 #define F81232_SET_REGISTER		0x40
+#define F81534A_ACCESS_REG_RETRY	2
 
 #define SERIAL_BASE_ADDRESS		0x0120
 #define RECEIVE_BUFFER_REGISTER		(0x00 + SERIAL_BASE_ADDRESS)
@@ -101,6 +111,8 @@ MODULE_DEVICE_TABLE(usb, combined_id_table);
 #define F81534A_GPIO_MODE1_OUTPUT	BIT(1)
 #define F81534A_GPIO_MODE0_OUTPUT	BIT(0)
 
+#define F81534A_CTRL_CMD_ENABLE_PORT	0x116
+
 struct f81232_private {
 	struct mutex lock;
 	u8 modem_control;
@@ -848,6 +860,93 @@ static void f81232_lsr_worker(struct work_struct *work)
 		dev_warn(&port->dev, "read LSR failed: %d\n", status);
 }
 
+static int f81534a_ctrl_set_register(struct usb_interface *intf, u16 reg,
+					u16 size, void *val)
+{
+	struct usb_device *dev = interface_to_usbdev(intf);
+	int retry = F81534A_ACCESS_REG_RETRY;
+	int status;
+	u8 *tmp;
+
+	tmp = kmemdup(val, size, GFP_KERNEL);
+	if (!tmp)
+		return -ENOMEM;
+
+	while (retry--) {
+		status = usb_control_msg(dev,
+					usb_sndctrlpipe(dev, 0),
+					F81232_REGISTER_REQUEST,
+					F81232_SET_REGISTER,
+					reg,
+					0,
+					tmp,
+					size,
+					USB_CTRL_SET_TIMEOUT);
+		if (status < 0) {
+			status = usb_translate_errors(status);
+			if (status == -EIO)
+				continue;
+		} else if (status != size) {
+			/* Retry on short transfers */
+			status = -EIO;
+			continue;
+		} else {
+			status = 0;
+		}
+
+		break;
+	}
+
+	if (status) {
+		dev_err(&intf->dev, "failed to set register 0x%x: %d\n",
+				reg, status);
+	}
+
+	kfree(tmp);
+	return status;
+}
+
+static int f81534a_ctrl_enable_all_ports(struct usb_interface *intf, bool en)
+{
+	unsigned char enable[2] = {0};
+	int status;
+
+	/*
+	 * Enable all available serial ports, define as following:
+	 * bit 15	: Reset behavior (when HUB got soft reset)
+	 *			0: maintain all serial port enabled state.
+	 *			1: disable all serial port.
+	 * bit 0~11	: Serial port enable bit.
+	 */
+	if (en) {
+		enable[0] = 0xff;
+		enable[1] = 0x8f;
+	}
+
+	status = f81534a_ctrl_set_register(intf, F81534A_CTRL_CMD_ENABLE_PORT,
+			sizeof(enable), enable);
+	if (status)
+		dev_err(&intf->dev, "failed to enable ports: %d\n", status);
+
+	return status;
+}
+
+static int f81534a_ctrl_probe(struct usb_interface *intf,
+				const struct usb_device_id *id)
+{
+	return f81534a_ctrl_enable_all_ports(intf, true);
+}
+
+static void f81534a_ctrl_disconnect(struct usb_interface *intf)
+{
+	f81534a_ctrl_enable_all_ports(intf, false);
+}
+
+static int f81534a_ctrl_resume(struct usb_interface *intf)
+{
+	return f81534a_ctrl_enable_all_ports(intf, true);
+}
+
 static int f81232_port_probe(struct usb_serial_port *port)
 {
 	struct f81232_private *priv;
@@ -975,7 +1074,41 @@ static struct usb_serial_driver * const serial_drivers[] = {
 	NULL,
 };
 
-module_usb_serial_driver(serial_drivers, combined_id_table);
+static struct usb_driver f81534a_ctrl_driver = {
+	.name =		"f81534a_ctrl",
+	.id_table =	f81534a_ctrl_id_table,
+	.probe =	f81534a_ctrl_probe,
+	.disconnect =	f81534a_ctrl_disconnect,
+	.resume =	f81534a_ctrl_resume,
+};
+
+static int __init f81232_init(void)
+{
+	int status;
+
+	status = usb_register_driver(&f81534a_ctrl_driver, THIS_MODULE,
+			KBUILD_MODNAME);
+	if (status)
+		return status;
+
+	status = usb_serial_register_drivers(serial_drivers, KBUILD_MODNAME,
+			combined_id_table);
+	if (status) {
+		usb_deregister(&f81534a_ctrl_driver);
+		return status;
+	}
+
+	return 0;
+}
+
+static void __exit f81232_exit(void)
+{
+	usb_serial_deregister_drivers(serial_drivers);
+	usb_deregister(&f81534a_ctrl_driver);
+}
+
+module_init(f81232_init);
+module_exit(f81232_exit);
 
 MODULE_DESCRIPTION("Fintek F81232/532A/534A/535/536 USB to serial driver");
 MODULE_AUTHOR("Greg Kroah-Hartman <gregkh@linuxfoundation.org>");