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path: root/drivers/usb/serial/ch341.c
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Diffstat (limited to 'drivers/usb/serial/ch341.c')
-rw-r--r--drivers/usb/serial/ch341.c57
1 files changed, 54 insertions, 3 deletions
diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c
index 2830766f5b3..59eff721fcc 100644
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -56,6 +56,18 @@
#define CH341_BAUDBASE_FACTOR 1532620800
#define CH341_BAUDBASE_DIVMAX 3
+/* Break support - the information used to implement this was gleaned from
+ * the Net/FreeBSD uchcom.c driver by Takanori Watanabe. Domo arigato.
+ */
+
+#define CH341_REQ_WRITE_REG 0x9A
+#define CH341_REQ_READ_REG 0x95
+#define CH341_REG_BREAK1 0x05
+#define CH341_REG_BREAK2 0x18
+#define CH341_NBREAK_BITS_REG1 0x01
+#define CH341_NBREAK_BITS_REG2 0x40
+
+
static int debug;
static struct usb_device_id id_table [] = {
@@ -300,8 +312,7 @@ static void ch341_close(struct usb_serial_port *port)
/* open this device, set default parameters */
-static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port,
- struct file *filp)
+static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
{
struct usb_serial *serial = port->serial;
struct ch341_private *priv = usb_get_serial_port_data(serial->port[0]);
@@ -333,7 +344,7 @@ static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port,
return -EPROTO;
}
- r = usb_serial_generic_open(tty, port, filp);
+ r = usb_serial_generic_open(tty, port);
out: return r;
}
@@ -374,6 +385,45 @@ static void ch341_set_termios(struct tty_struct *tty,
*/
}
+static void ch341_break_ctl(struct tty_struct *tty, int break_state)
+{
+ const uint16_t ch341_break_reg =
+ CH341_REG_BREAK1 | ((uint16_t) CH341_REG_BREAK2 << 8);
+ struct usb_serial_port *port = tty->driver_data;
+ int r;
+ uint16_t reg_contents;
+ uint8_t break_reg[2];
+
+ dbg("%s()", __func__);
+
+ r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
+ ch341_break_reg, 0, break_reg, sizeof(break_reg));
+ if (r < 0) {
+ printk(KERN_WARNING "%s: USB control read error whilst getting"
+ " break register contents.\n", __FILE__);
+ return;
+ }
+ dbg("%s - initial ch341 break register contents - reg1: %x, reg2: %x",
+ __func__, break_reg[0], break_reg[1]);
+ if (break_state != 0) {
+ dbg("%s - Enter break state requested", __func__);
+ break_reg[0] &= ~CH341_NBREAK_BITS_REG1;
+ break_reg[1] &= ~CH341_NBREAK_BITS_REG2;
+ } else {
+ dbg("%s - Leave break state requested", __func__);
+ break_reg[0] |= CH341_NBREAK_BITS_REG1;
+ break_reg[1] |= CH341_NBREAK_BITS_REG2;
+ }
+ dbg("%s - New ch341 break register contents - reg1: %x, reg2: %x",
+ __func__, break_reg[0], break_reg[1]);
+ reg_contents = (uint16_t)break_reg[0] | ((uint16_t)break_reg[1] << 8);
+ r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
+ ch341_break_reg, reg_contents);
+ if (r < 0)
+ printk(KERN_WARNING "%s: USB control write error whilst setting"
+ " break register contents.\n", __FILE__);
+}
+
static int ch341_tiocmset(struct tty_struct *tty, struct file *file,
unsigned int set, unsigned int clear)
{
@@ -577,6 +627,7 @@ static struct usb_serial_driver ch341_device = {
.close = ch341_close,
.ioctl = ch341_ioctl,
.set_termios = ch341_set_termios,
+ .break_ctl = ch341_break_ctl,
.tiocmget = ch341_tiocmget,
.tiocmset = ch341_tiocmset,
.read_int_callback = ch341_read_int_callback,