From: Tim Small <tim@xxxxxxxxxxxxxxxx>
Here is a patch to the ch341 driver which adds serial break support.
Signed-off-by: Tim Small <tim@xxxxxxxxxxx>
Cc: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
drivers/usb/serial/ch341.c | 52 ++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 52 insertions(+), 0 deletions(-)
diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c
index 8c894a7..59eff72 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 [] = {
@@ -373,6 +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)
{
@@ -576,6 +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,
--
1.6.4.2
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