[PATCH V5 2/8] USB: f81232: implement read IIR/MSR with endpoint

[Peter Hung <hpeter@gmail.com>]

The interrupt Endpoint will report current IIR. If we got IIR with MSR Changed
, We will do read MSR with interrupt_work worker to do f81232_read_msr() func.

Signed-off-by: Peter Hung <hpeter+linux_kernel@gmail.com>
---
 drivers/usb/serial/f81232.c | 109 ++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 100 insertions(+), 9 deletions(-)

diff --git a/drivers/usb/serial/f81232.c b/drivers/usb/serial/f81232.c
index 669a2f2..ec4609d 100644
--- a/drivers/usb/serial/f81232.c
+++ b/drivers/usb/serial/f81232.c
@@ -23,6 +23,7 @@
 #include <linux/uaccess.h>
 #include <linux/usb.h>
 #include <linux/usb/serial.h>
+#include <linux/serial_reg.h>
 
 static const struct usb_device_id id_table[] = {
 	{ USB_DEVICE(0x1934, 0x0706) },
@@ -30,6 +31,13 @@ static const struct usb_device_id id_table[] = {
 };
 MODULE_DEVICE_TABLE(usb, id_table);
 
+/* USB Control EP parameter */
+#define F81232_REGISTER_REQUEST 0xA0
+#define F81232_GET_REGISTER 0xc0
+
+#define SERIAL_BASE_ADDRESS	   0x0120
+#define MODEM_STATUS_REGISTER      (0x06 + SERIAL_BASE_ADDRESS)
+
 #define CONTROL_DTR			0x01
 #define CONTROL_RTS			0x02
 
@@ -48,19 +56,92 @@ struct f81232_private {
 	spinlock_t lock;
 	u8 line_control;
 	u8 modem_status;
+
+	struct work_struct interrupt_work;
+	struct usb_serial_port *port;
 };
 
-static void f81232_update_line_status(struct usb_serial_port *port,
+static int f81232_get_register(struct usb_serial_port *port,
+							  u16 reg, u8 *data)
+{
+	int status;
+	struct usb_device *dev = port->serial->dev;
+
+	status = usb_control_msg(dev,
+			 usb_rcvctrlpipe(dev, 0),
+			 F81232_REGISTER_REQUEST,
+			 F81232_GET_REGISTER,
+			 reg,
+			 0,
+			 data,
+			 sizeof(*data),
+			 USB_CTRL_GET_TIMEOUT);
+	if (status < 0)
+		dev_err(&port->dev, "%s status: %d\n", __func__, status);
+
+	return status;
+}
+
+static void f81232_read_msr(struct usb_serial_port *port)
+{
+	int status;
+	unsigned long flags;
+	u8 current_msr;
+	struct tty_struct *tty;
+	struct f81232_private *priv = usb_get_serial_port_data(port);
+
+	status = f81232_get_register(port, MODEM_STATUS_REGISTER,
+			&current_msr);
+	if (status < 0) {
+		/* Retain the error even reported in f81232_get_register()
+		     to make debug easily :D */
+		dev_err(&port->dev, "%s fail, status: %d\n", __func__, status);
+		return;
+	}
+
+	if (!(current_msr & UART_MSR_ANY_DELTA))
+		return;
+
+	tty = tty_port_tty_get(&port->port);
+	if (tty) {
+		if (current_msr & UART_MSR_DDCD) {
+			usb_serial_handle_dcd_change(port, tty,
+				current_msr & UART_MSR_DCD);
+		}
+
+		tty_kref_put(tty);
+	}
+
+	spin_lock_irqsave(&priv->lock, flags);
+	priv->modem_status = current_msr;
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	wake_up_interruptible(&port->port.delta_msr_wait);
+}
+
+static void f81232_update_modem_status(struct usb_serial_port *port,
 				      unsigned char *data,
 				      unsigned int actual_length)
 {
-	/*
-	 * FIXME: Update port->icount, and call
-	 *
-	 *		wake_up_interruptible(&port->port.delta_msr_wait);
-	 *
-	 *	  on MSR changes.
-	 */
+	struct f81232_private *priv = usb_get_serial_port_data(port);
+
+	if (!actual_length)
+		return;
+
+	switch (data[0] & 0x07) {
+	case 0x00: /* msr change */
+		dev_dbg(&port->dev, "IIR: MSR Change: %x\n", data[0]);
+		schedule_work(&priv->interrupt_work);
+		break;
+	case 0x02: /* tx-empty */
+		break;
+	case 0x04: /* rx data available */
+		break;
+	case 0x06: /* lsr change */
+		/* we can forget it. the LSR will read from bulk-in */
+		dev_dbg(&port->dev, "IIR: LSR Change: %x\n", data[0]);
+		break;
+	}
 }
 
 static void f81232_read_int_callback(struct urb *urb)
@@ -91,7 +172,7 @@ static void f81232_read_int_callback(struct urb *urb)
 	usb_serial_debug_data(&port->dev, __func__,
 			      urb->actual_length, urb->transfer_buffer);
 
-	f81232_update_line_status(port, data, actual_length);
+	f81232_update_modem_status(port, data, actual_length);
 
 exit:
 	retval = usb_submit_urb(urb, GFP_ATOMIC);
@@ -270,6 +351,14 @@ static int f81232_ioctl(struct tty_struct *tty,
 	return -ENOIOCTLCMD;
 }
 
+static void  f81232_interrupt_work(struct work_struct *work)
+{
+	struct f81232_private *priv =
+		container_of(work, struct f81232_private, interrupt_work);
+
+	f81232_read_msr(priv->port);
+}
+
 static int f81232_port_probe(struct usb_serial_port *port)
 {
 	struct f81232_private *priv;
@@ -279,10 +368,12 @@ static int f81232_port_probe(struct usb_serial_port *port)
 		return -ENOMEM;
 
 	spin_lock_init(&priv->lock);
+	INIT_WORK(&priv->interrupt_work,  f81232_interrupt_work);
 
 	usb_set_serial_port_data(port, priv);
 
 	port->port.drain_delay = 256;
+	priv->port = port;
 
 	return 0;
 }
-- 
1.9.1