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Subject[PATCH 1/5] USB: serial: f81232: clear overrun flag
Date
The F81232 will report data and LSR with bulk like following format:
bulk-in data: [LSR(1Byte)+DATA(1Byte)][LSR(1Byte)+DATA(1Byte)]...

LSR will auto clear frame/parity/break error flag when reading by H/W,
but overrrun will only cleared when reading LSR. So this patch add a
worker to read LSR when OE.

Signed-off-by: Ji-Ze Hong (Peter Hong) <hpeter+linux_kernel@gmail.com>
---
drivers/usb/serial/f81232.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)

diff --git a/drivers/usb/serial/f81232.c b/drivers/usb/serial/f81232.c
index 96036f87b1de..46836041c50e 100644
--- a/drivers/usb/serial/f81232.c
+++ b/drivers/usb/serial/f81232.c
@@ -41,12 +41,14 @@ MODULE_DEVICE_TABLE(usb, id_table);
#define FIFO_CONTROL_REGISTER (0x02 + SERIAL_BASE_ADDRESS)
#define LINE_CONTROL_REGISTER (0x03 + SERIAL_BASE_ADDRESS)
#define MODEM_CONTROL_REGISTER (0x04 + SERIAL_BASE_ADDRESS)
+#define LINE_STATUS_REGISTER (0x05 + SERIAL_BASE_ADDRESS)
#define MODEM_STATUS_REGISTER (0x06 + SERIAL_BASE_ADDRESS)

struct f81232_private {
struct mutex lock;
u8 modem_control;
u8 modem_status;
+ struct work_struct lsr_work;
struct work_struct interrupt_work;
struct usb_serial_port *port;
};
@@ -282,6 +284,7 @@ static void f81232_read_int_callback(struct urb *urb)
static void f81232_process_read_urb(struct urb *urb)
{
struct usb_serial_port *port = urb->context;
+ struct f81232_private *priv = usb_get_serial_port_data(port);
unsigned char *data = urb->transfer_buffer;
char tty_flag;
unsigned int i;
@@ -315,6 +318,7 @@ static void f81232_process_read_urb(struct urb *urb)

if (lsr & UART_LSR_OE) {
port->icount.overrun++;
+ schedule_work(&priv->lsr_work);
tty_insert_flip_char(&port->port, 0,
TTY_OVERRUN);
}
@@ -623,6 +627,21 @@ static void f81232_interrupt_work(struct work_struct *work)
f81232_read_msr(priv->port);
}

+static void f81232_lsr_worker(struct work_struct *work)
+{
+ struct f81232_private *priv;
+ struct usb_serial_port *port;
+ int status;
+ u8 tmp;
+
+ priv = container_of(work, struct f81232_private, lsr_work);
+ port = priv->port;
+
+ status = f81232_get_register(port, LINE_STATUS_REGISTER, &tmp);
+ if (status)
+ dev_warn(&port->dev, "read LSR failed: %d\n", status);
+}
+
static int f81232_port_probe(struct usb_serial_port *port)
{
struct f81232_private *priv;
@@ -633,6 +652,7 @@ static int f81232_port_probe(struct usb_serial_port *port)

mutex_init(&priv->lock);
INIT_WORK(&priv->interrupt_work, f81232_interrupt_work);
+ INIT_WORK(&priv->lsr_work, f81232_lsr_worker);

usb_set_serial_port_data(port, priv);

--
2.7.4
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