[PATCH] USB: otg: Fix error 32 when enable hardware flow control.

[Pho Tran]

When hardware flow control is enabled,
don't allow host send MHS command to cp210x.

Signed-off-by: Pho Tran<pho.t...@silabs.com>
---
 drivers/usb/serial/cp210x.c | 32 +++++++++++++++++++++++++++++++-
 1 file changed, 31 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index fbb10dfc56e3..f231cecdaf7d 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -1204,6 +1204,7 @@ static int cp210x_tiocmset(struct tty_struct *tty,
                unsigned int set, unsigned int clear)
 {
        struct usb_serial_port *port = tty->driver_data;
+
        return cp210x_tiocmset_port(port, set, clear);
 }
 
@@ -1211,6 +1212,11 @@ static int cp210x_tiocmset_port(struct usb_serial_port 
*port,
                unsigned int set, unsigned int clear)
 {
        u16 control = 0;
+       struct cp210x_flow_ctl flow_ctl;
+       u32 ctl_hs = 0;
+       u32 flow_repl = 0;
+       bool auto_dtr = false;
+       bool auto_rts = false;
 
        if (set & TIOCM_RTS) {
                control |= CONTROL_RTS;
@@ -1230,6 +1236,30 @@ static int cp210x_tiocmset_port(struct usb_serial_port 
*port,
        }
 
        dev_dbg(&port->dev, "%s - control = 0x%.4x\n", __func__, control);
+       /*
+        *      Don't send MHS command if device in hardware flowcontrol mode
+        */
+       cp210x_read_reg_block(port, CP210X_GET_FLOW, &flow_ctl,
+                               sizeof(flow_ctl));
+       ctl_hs = le32_to_cpu(flow_ctl.ulControlHandshake);
+       flow_repl = le32_to_cpu(flow_ctl.ulFlowReplace);
+
+       if (CP210X_SERIAL_DTR_SHIFT(CP210X_SERIAL_DTR_FLOW_CTL)
+               == (ctl_hs & CP210X_SERIAL_DTR_MASK))
+               auto_dtr = true;
+       else
+               auto_dtr = false;
+
+       if (CP210X_SERIAL_RTS_SHIFT(CP210X_SERIAL_RTS_FLOW_CTL)
+               == (flow_repl & CP210X_SERIAL_RTS_MASK))
+               auto_rts = true;
+       else
+               auto_rts = false;
+
+       if (auto_dtr || auto_rts) {
+               dev_dbg(&port->dev, "Don't set MHS when while device in flow 
control mode\n");
+               return 0;
+       }
 
        return cp210x_write_u16_reg(port, CP210X_SET_MHS, control);
 }
@@ -1256,7 +1286,7 @@ static int cp210x_tiocmget(struct tty_struct *tty)
                |((control & CONTROL_RTS) ? TIOCM_RTS : 0)
                |((control & CONTROL_CTS) ? TIOCM_CTS : 0)
                |((control & CONTROL_DSR) ? TIOCM_DSR : 0)
-               |((control & CONTROL_RING)? TIOCM_RI  : 0)
+               |((control & CONTROL_RING) ? TIOCM_RI  : 0)
                |((control & CONTROL_DCD) ? TIOCM_CD  : 0);
 
        dev_dbg(&port->dev, "%s - control = 0x%.2x\n", __func__, control);
-- 
2.17.1