serial: omap: do not override settings for RS485 support

commit 51f93776b84dee23e44a7be880736669a01cec2b upstream.

The drivers RS485 support is deactivated if there is no RTS GPIO available.
This is done by nullifying the ports rs485_supported struct. After that
however the settings in serial_omap_rs485_supported are assigned to the
same structure unconditionally, which results in an unintended reactivation
of RS485 support.

Fix this by moving the assignment to the beginning of
serial_omap_probe_rs485() and thus before uart_get_rs485_mode() gets
called.

Also replace the assignment of rs485_config() to have the complete RS485
setup in one function.

Fixes: e2752ae3cfc9 ("serial: omap: Disallow RS-485 if rts-gpio is not specified")
Cc:  <stable@vger.kernel.org>
Signed-off-by: Lino Sanfilippo <l.sanfilippo@kunbus.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20240103061818.564-7-l.sanfilippo@kunbus.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index 0ead88c..135a838 100644 (file)
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -1483,6 +1483,13 @@ static struct omap_uart_port_info *of_get_uart_port_info(struct device *dev)
        return omap_up_info;
 }
 
+static const struct serial_rs485 serial_omap_rs485_supported = {
+       .flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND |
+                SER_RS485_RX_DURING_TX,
+       .delay_rts_before_send = 1,
+       .delay_rts_after_send = 1,
+};
+
 static int serial_omap_probe_rs485(struct uart_omap_port *up,
                                   struct device *dev)
 {
@@ -1497,6 +1504,9 @@ static int serial_omap_probe_rs485(struct uart_omap_port *up,
        if (!np)
                return 0;
 
+       up->port.rs485_config = serial_omap_config_rs485;
+       up->port.rs485_supported = serial_omap_rs485_supported;
+
        ret = uart_get_rs485_mode(&up->port);
        if (ret)
                return ret;
@@ -1531,13 +1541,6 @@ static int serial_omap_probe_rs485(struct uart_omap_port *up,
        return 0;
 }
 
-static const struct serial_rs485 serial_omap_rs485_supported = {
-       .flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND |
-                SER_RS485_RX_DURING_TX,
-       .delay_rts_before_send = 1,
-       .delay_rts_after_send = 1,
-};
-
 static int serial_omap_probe(struct platform_device *pdev)
 {
        struct omap_uart_port_info *omap_up_info = dev_get_platdata(&pdev->dev);
@@ -1604,17 +1607,11 @@ static int serial_omap_probe(struct platform_device *pdev)
                dev_info(up->port.dev, "no wakeirq for uart%d\n",
                         up->port.line);
 
-       ret = serial_omap_probe_rs485(up, &pdev->dev);
-       if (ret < 0)
-               goto err_rs485;
-
        sprintf(up->name, "OMAP UART%d", up->port.line);
        up->port.mapbase = mem->start;
        up->port.membase = base;
        up->port.flags = omap_up_info->flags;
        up->port.uartclk = omap_up_info->uartclk;
-       up->port.rs485_config = serial_omap_config_rs485;
-       up->port.rs485_supported = serial_omap_rs485_supported;
        if (!up->port.uartclk) {
                up->port.uartclk = DEFAULT_CLK_SPEED;
                dev_warn(&pdev->dev,
@@ -1622,6 +1619,10 @@ static int serial_omap_probe(struct platform_device *pdev)
                         DEFAULT_CLK_SPEED);
        }
 
+       ret = serial_omap_probe_rs485(up, &pdev->dev);
+       if (ret < 0)
+               goto err_rs485;
+
        up->latency = PM_QOS_CPU_LATENCY_DEFAULT_VALUE;
        up->calc_latency = PM_QOS_CPU_LATENCY_DEFAULT_VALUE;
        cpu_latency_qos_add_request(&up->pm_qos_request, up->latency);