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Subject[PATCH] USB: otg: Fix error 32 when enable hardware flow control.
Date
When hardware flow control is enabled,
don't allow host send MHS command to cp210x.

Signed-off-by: Pho Tran<pho.tran@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
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