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authorMaarten Brock <m.brock@vanmierlo.com>2019-11-25 18:45:29 +0530
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-01-14 14:34:04 +0100
commit422c6d3b09afb187b5aeedc3a99d759703023be0 (patch)
tree6acd6145dcf8d035190c6dc37c133387ce05d53b /drivers/tty
parent67e977f32461f70c2b838d43107ff128f595485c (diff)
downloadlinux-422c6d3b09afb187b5aeedc3a99d759703023be0.tar.gz
serial: xilinx_uartps: Let get_mctrl return status
Some of the applications like microcom do not work if
modem is disabled. To fix them we always return
TIOCM_CTS | TIOCM_DSR | TIOCM_CAR instead of 0 when
using cts_override. Make get_mctrl return actual status
when not using cts_override.

Signed-off-by: Maarten Brock <m.brock@vanmierlo.com>
Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Link: https://lore.kernel.org/r/1574687731-21563-1-git-send-email-shubhrajyoti.datta@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/serial/xilinx_uartps.c28
1 files changed, 25 insertions, 3 deletions
diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index 2b5606469bed..f33b89587786 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -154,6 +154,16 @@ MODULE_PARM_DESC(rx_timeout, "Rx timeout, 1-255");
 #define CDNS_UART_MODEMCR_DTR	0x00000001 /* Data Terminal Ready */
 
 /*
+ * Modem Status register:
+ * The read/write Modem Status register reports the interface with the modem
+ * or data set, or a peripheral device emulating a modem.
+ */
+#define CDNS_UART_MODEMSR_DCD	BIT(7) /* Data Carrier Detect */
+#define CDNS_UART_MODEMSR_RI	BIT(6) /* Ting Indicator */
+#define CDNS_UART_MODEMSR_DSR	BIT(5) /* Data Set Ready */
+#define CDNS_UART_MODEMSR_CTS	BIT(4) /* Clear To Send */
+
+/*
  * Channel Status Register:
  * The channel status register (CSR) is provided to enable the control logic
  * to monitor the status of bits in the channel interrupt status register,
@@ -1003,12 +1013,24 @@ static void cdns_uart_config_port(struct uart_port *port, int flags)
  */
 static unsigned int cdns_uart_get_mctrl(struct uart_port *port)
 {
+	u32 val;
+	unsigned int mctrl = 0;
 	struct cdns_uart *cdns_uart_data = port->private_data;
 
 	if (cdns_uart_data->cts_override)
-		return 0;
-
-	return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
+		return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
+
+	val = readl(port->membase + CDNS_UART_MODEMSR);
+	if (val & CDNS_UART_MODEMSR_CTS)
+		mctrl |= TIOCM_CTS;
+	if (val & CDNS_UART_MODEMSR_DSR)
+		mctrl |= TIOCM_DSR;
+	if (val & CDNS_UART_MODEMSR_RI)
+		mctrl |= TIOCM_RNG;
+	if (val & CDNS_UART_MODEMSR_DCD)
+		mctrl |= TIOCM_CAR;
+
+	return mctrl;
 }
 
 static void cdns_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)