This patch adds DCD line support to CP210x USB serial driver.
First it enables CP210x events embedding to incoming URB's by calling:
cp210x_set_config_single(port, CP210X_EMBED_EVENTS, CP210X_ESCCHAR);
Then it parses incoming URB's via custom routine:
cp210x_process_read_urb(...)
searches for event sequences and handles all of DCD changes calling
usb_serial_handle_dcd_change(...)
Signed-off-by: Valentin Yakovenkov <yakovenkov@xxxxxxxxx>
---
drivers/usb/serial/cp210x.c | 115 +++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 114 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index 7a76fe4..d9cba4e 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -46,6 +46,7 @@ static void cp210x_break_ctl(struct tty_struct *, int);
static int cp210x_startup(struct usb_serial *);
static void cp210x_release(struct usb_serial *);
static void cp210x_dtr_rts(struct usb_serial_port *p, int on);
+static void cp210x_process_read_urb(struct urb *urb);
static const struct usb_device_id id_table[] = {
{ USB_DEVICE(0x045B, 0x0053) }, /* Renesas RX610 RX-Stick */
@@ -201,8 +202,17 @@ static const struct usb_device_id id_table[] = {
MODULE_DEVICE_TABLE(usb, id_table);
+#define CP210X_ESCCHAR 0x1e
+#define CP210X_STATE_IDLE 0
+#define CP210X_STATE_ESC 1
+#define CP210X_STATE_LS0 2
+#define CP210X_STATE_LS1 3
+#define CP210X_STATE_LS 4
+#define CP210X_STATE_MS 5
+
struct cp210x_serial_private {
__u8 bInterfaceNumber;
+ int cp210x_tstate;
};
static struct usb_serial_driver cp210x_device = {
@@ -222,7 +232,8 @@ static struct usb_serial_driver cp210x_device = {
.tiocmset = cp210x_tiocmset,
.attach = cp210x_startup,
.release = cp210x_release,
- .dtr_rts = cp210x_dtr_rts
+ .dtr_rts = cp210x_dtr_rts,
+ .process_read_urb = cp210x_process_read_urb,
};
static struct usb_serial_driver * const serial_drivers[] = {
@@ -460,6 +471,11 @@ static int cp210x_open(struct tty_struct *tty, struct usb_serial_port *port)
{
int result;
+ struct usb_serial *serial = port->serial;
+ struct cp210x_serial_private *spriv = usb_get_serial_data(serial);
+
+ spriv->cp210x_tstate = CP210X_STATE_IDLE;
+
result = cp210x_set_config_single(port, CP210X_IFC_ENABLE,
UART_ENABLE);
if (result) {
@@ -474,6 +490,15 @@ static int cp210x_open(struct tty_struct *tty, struct usb_serial_port *port)
if (tty)
cp210x_change_speed(tty, port, NULL);
+ /* Enable events embedding to data stream */
+ result = cp210x_set_config_single(port, CP210X_EMBED_EVENTS,
+ CP210X_ESCCHAR);
+ if (result) {
+ dev_err(&port->dev, "%s - Unable to enable event embedding on UART\n",
+ __func__);
+ return result;
+ }
+
return usb_serial_generic_open(tty, port);
}
@@ -483,6 +508,94 @@ static void cp210x_close(struct usb_serial_port *port)
cp210x_set_config_single(port, CP210X_IFC_ENABLE, UART_DISABLE);
}
+static void cp210x_process_read_urb(struct urb *urb)
+{
+ struct usb_serial_port *port = urb->context;
+ char *ch = (char *)urb->transfer_buffer;
+ char *tbuf = (char *)urb->transfer_buffer;
+ int i;
+ int tcnt = 0;
+ struct usb_serial *serial = port->serial;
+ struct cp210x_serial_private *spriv = usb_get_serial_data(serial);
+
+ if (!urb->actual_length)
+ return;
+
+ /* Process escape chars */
+ for (i = 0; i < urb->actual_length; i++) {
+ char c = ch[i];
+
+ switch (spriv->cp210x_tstate) {
+ case CP210X_STATE_IDLE:
+ if (c == CP210X_ESCCHAR)
+ spriv->cp210x_tstate = CP210X_STATE_ESC;
+ else
+ tbuf[tcnt++] = c;
+ break;
+
+ case CP210X_STATE_ESC:
+ if (c == 0x01)
+ spriv->cp210x_tstate = CP210X_STATE_LS0;
+ else if (c == 0x02)
+ spriv->cp210x_tstate = CP210X_STATE_LS;
+ else if (c == 0x03)
+ spriv->cp210x_tstate = CP210X_STATE_MS;
+ else {
+ tbuf[tcnt++] = (c == 0x00) ? CP210X_ESCCHAR : c;
+ spriv->cp210x_tstate = CP210X_STATE_IDLE;
+ }
+ break;
+
+ case CP210X_STATE_LS0:
+ spriv->cp210x_tstate = CP210X_STATE_LS1;
+ break;
+
+ case CP210X_STATE_LS1:
+ tbuf[tcnt++] = c;
+ spriv->cp210x_tstate = CP210X_STATE_IDLE;
+ break;
+
+ case CP210X_STATE_LS:
+ spriv->cp210x_tstate = CP210X_STATE_IDLE;
+ break;
+
+ case CP210X_STATE_MS:
+ if (c & 0x08) {
+ /* DCD change event */
+ struct tty_struct *tty;
+
+ port->icount.dcd++;
+ tty = tty_port_tty_get(&port->port);
+ if (tty)
+ usb_serial_handle_dcd_change(port, tty,
+ c & 0x80);
+ tty_kref_put(tty);
+
+ }
+ wake_up_interruptible(&port->port.delta_msr_wait);
+ spriv->cp210x_tstate = CP210X_STATE_IDLE;
+ break;
+ }
+ }
+
+ /*
+ * The per character mucking around with sysrq path it too slow for
+ * stuff like 3G modems, so shortcircuit it in the 99.9999999% of
+ * cases where the USB serial is not a console anyway.
+ */
+ if (!port->port.console || !port->sysrq) {
+ tty_insert_flip_string(&port->port, tbuf, tcnt);
+ } else {
+ ch = tbuf;
+ for (i = 0; i < tcnt; i++, ch++) {
+ if (!usb_serial_handle_sysrq_char(port, *ch))
+ tty_insert_flip_char(&port->port, *ch,
+ TTY_NORMAL);
+ }
+ }
+ tty_flip_buffer_push(&port->port);
+}
+
/*
* cp210x_get_termios
* Reads the baud rate, data bits, parity, stop bits and flow control mode
--
2.5.0
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