serial: ar933x: Fill in rs485_supported

Add information on supported serial_rs485 features.

In the case where RTS is lacking, RS485 cannot be enabled so provide
zero rs485_supported for that case. Perhaps it would make sense to not
provide rs485_config() at all in that case but such a change would have
userspace visible impact/change in behavior so this patch does not
attempt it.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606100433.13793-14-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/ar933x_uart.c b/drivers/tty/serial/ar933x_uart.c
index 6269dbf935460771fa80e61ab180179d3b3f4e7f..ab2c5b2a1ce8225af6f86b7b130409ceb045d9f5 100644 (file)
--- a/drivers/tty/serial/ar933x_uart.c
+++ b/drivers/tty/serial/ar933x_uart.c
@@ -702,6 +702,11 @@ static struct uart_driver ar933x_uart_driver = {
        .cons           = NULL, /* filled in runtime */
 };
 
+static const struct serial_rs485 ar933x_no_rs485 = {};
+static const struct serial_rs485 ar933x_rs485_supported = {
+       .flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND,
+};
+
 static int ar933x_uart_probe(struct platform_device *pdev)
 {
        struct ar933x_uart_port *up;
@@ -773,6 +778,7 @@ static int ar933x_uart_probe(struct platform_device *pdev)
        port->fifosize = AR933X_UART_FIFO_SIZE;
        port->ops = &ar933x_uart_ops;
        port->rs485_config = ar933x_config_rs485;
+       port->rs485_supported = &ar933x_rs485_supported;
 
        baud = ar933x_uart_get_baud(port->uartclk, AR933X_UART_MAX_SCALE, 1);
        up->min_baud = max_t(unsigned int, baud, AR933X_UART_MIN_BAUD);
@@ -796,6 +802,7 @@ static int ar933x_uart_probe(struct platform_device *pdev)
            !up->rts_gpiod) {
                dev_err(&pdev->dev, "lacking rts-gpio, disabling RS485\n");
                port->rs485.flags &= ~SER_RS485_ENABLED;
+               port->rs485_supported = &ar933x_no_rs485;
        }
 
 #ifdef CONFIG_SERIAL_AR933X_CONSOLE