serial: ns16550: add setconfig support

Add possibility to update the serial parity used.

Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Hannes Schmelzer <hannes.schmelzer@br-automation.com>

diff --git a/drivers/serial/ns16550.c b/drivers/serial/ns16550.c
index 1e6fc6c66839c844aaaf1c808633ba020b085fa2..f21c240e64aa2d7802841f719e8ddbb017d2f7be 100644 (file)
--- a/drivers/serial/ns16550.c
+++ b/drivers/serial/ns16550.c
@@ -148,10 +148,13 @@ int ns16550_calc_divisor(NS16550_t port, int clock, int baudrate)
 
 static void NS16550_setbrg(NS16550_t com_port, int baud_divisor)
 {
-       serial_out(UART_LCR_BKSE | UART_LCRVAL, &com_port->lcr);
+       /* to keep serial format, read lcr before writing BKSE */
+       int lcr_val = serial_in(&com_port->lcr) & ~UART_LCR_BKSE;
+
+       serial_out(UART_LCR_BKSE | lcr_val, &com_port->lcr);
        serial_out(baud_divisor & 0xff, &com_port->dll);
        serial_out((baud_divisor >> 8) & 0xff, &com_port->dlm);
-       serial_out(UART_LCRVAL, &com_port->lcr);
+       serial_out(lcr_val, &com_port->lcr);
 }
 
 void NS16550_init(NS16550_t com_port, int baud_divisor)
@@ -181,6 +184,8 @@ void NS16550_init(NS16550_t com_port, int baud_divisor)
 
        serial_out(UART_MCRVAL, &com_port->mcr);
        serial_out(ns16550_getfcr(com_port), &com_port->fcr);
+       /* initialize serial config to 8N1 before writing baudrate */
+       serial_out(UART_LCRVAL, &com_port->lcr);
        if (baud_divisor != -1)
                NS16550_setbrg(com_port, baud_divisor);
 #if defined(CONFIG_ARCH_OMAP2PLUS) || defined(CONFIG_SOC_DA8XX) || \
@@ -348,6 +353,39 @@ static int ns16550_serial_setbrg(struct udevice *dev, int baudrate)
        return 0;
 }
 
+static int ns16550_serial_setconfig(struct udevice *dev, uint serial_config)
+{
+       struct NS16550 *const com_port = dev_get_priv(dev);
+       int lcr_val = UART_LCR_WLS_8;
+       uint parity = SERIAL_GET_PARITY(serial_config);
+       uint bits = SERIAL_GET_BITS(serial_config);
+       uint stop = SERIAL_GET_STOP(serial_config);
+
+       /*
+        * only parity config is implemented, check if other serial settings
+        * are the default one.
+        */
+       if (bits != SERIAL_8_BITS || stop != SERIAL_ONE_STOP)
+               return -ENOTSUPP; /* not supported in driver*/
+
+       switch (parity) {
+       case SERIAL_PAR_NONE:
+               /* no bits to add */
+               break;
+       case SERIAL_PAR_ODD:
+               lcr_val |= UART_LCR_PEN;
+               break;
+       case SERIAL_PAR_EVEN:
+               lcr_val |= UART_LCR_PEN | UART_LCR_EPS;
+               break;
+       default:
+               return -ENOTSUPP; /* not supported in driver*/
+       }
+
+       serial_out(lcr_val, &com_port->lcr);
+       return 0;
+}
+
 int ns16550_serial_probe(struct udevice *dev)
 {
        struct NS16550 *const com_port = dev_get_priv(dev);
@@ -454,6 +492,7 @@ const struct dm_serial_ops ns16550_serial_ops = {
        .pending = ns16550_serial_pending,
        .getc = ns16550_serial_getc,
        .setbrg = ns16550_serial_setbrg,
+       .setconfig = ns16550_serial_setconfig
 };
 
 #if CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA)