[PATCH 4/5] tty: serial: uartlite: Initialize termios with fixed synthesis parameters

[Sean Anderson <sean.anderson@xxxxxxxx>]

This reads the various new devicetree parameters to discover how the
uart was configured when it was synthesized. Note that these properties
are fixed and undiscoverable. Once we have determined how the uart is
configured, we set the termios to let users know, and to initialize the
timeout to the correct value.

The defaults match ulite_console_setup. xlnx,use-parity,
xlnx,odd-parity, and xlnx,data-bits are optional since there were
in-tree users (and presumably out-of-tree users) who did not set them.

Signed-off-by: Sean Anderson <sean.anderson@xxxxxxxx>
---

 drivers/tty/serial/uartlite.c | 66 +++++++++++++++++++++++++++++++----
 1 file changed, 60 insertions(+), 6 deletions(-)

diff --git a/drivers/tty/serial/uartlite.c b/drivers/tty/serial/uartlite.c
index f42ccc40ffa6..39c17ab206ca 100644
--- a/drivers/tty/serial/uartlite.c
+++ b/drivers/tty/serial/uartlite.c
@@ -60,9 +60,20 @@
 static struct uart_port *console_port;
 #endif
 
+/**
+ * struct uartlite_data: Driver private data
+ * reg_ops: Functions to read/write registers
+ * clk: Our parent clock, if present
+ * baud: The baud rate configured when this device was synthesized
+ * parity: The parity settings, like for uart_set_options()
+ * bits: The number of data bits
+ */
 struct uartlite_data {
 	const struct uartlite_reg_ops *reg_ops;
 	struct clk *clk;
+	int baud;
+	int parity;
+	int bits;
 };
 
 struct uartlite_reg_ops {
@@ -652,6 +663,9 @@ static int ulite_assign(struct device *dev, int id, u32 base, int irq,
 	port->type = PORT_UNKNOWN;
 	port->line = id;
 	port->private_data = pdata;
+	/* Initialize the termios to what was configured at synthesis-time */
+	uart_set_options(port, NULL, pdata->baud, pdata->parity, pdata->bits,
+			 'n');
 
 	dev_set_drvdata(dev, port);
 
@@ -756,18 +770,58 @@ static int ulite_probe(struct platform_device *pdev)
 	struct uartlite_data *pdata;
 	int irq, ret;
 	int id = pdev->id;
-#ifdef CONFIG_OF
-	const __be32 *prop;
 
-	prop = of_get_property(pdev->dev.of_node, "port-number", NULL);
-	if (prop)
-		id = be32_to_cpup(prop);
-#endif
 	pdata = devm_kzalloc(&pdev->dev, sizeof(struct uartlite_data),
 			     GFP_KERNEL);
 	if (!pdata)
 		return -ENOMEM;
 
+	if (IS_ENABLED(CONFIG_OF)) {
+		const char *prop;
+		struct device_node *np = pdev->dev.of_node;
+		u32 val;
+
+		prop = "port-number";
+		ret = of_property_read_u32(np, prop, &id);
+		if (ret && ret != -EINVAL)
+of_err:
+			return dev_err_probe(&pdev->dev, ret,
+					     "could not read %s\n", prop);
+
+		prop = "current-speed";
+		ret = of_property_read_u32(np, prop, &pdata->baud);
+		if (ret)
+			goto of_err;
+
+		prop = "xlnx,use-parity";
+		ret = of_property_read_u32(np, prop, &val);
+		if (ret && ret != -EINVAL)
+			goto of_err;
+
+		if (val) {
+			prop = "xlnx,odd-parity";
+			ret = of_property_read_u32(np, prop, &val);
+			if (ret)
+				goto of_err;
+
+			if (val)
+				pdata->parity = 'o';
+			else
+				pdata->parity = 'e';
+		} else {
+			pdata->parity = 'n';
+		}
+
+		prop = "xlnx,data-bits";
+		ret = of_property_read_u32(np, prop, &pdata->bits);
+		if (ret && ret != -EINVAL)
+			goto of_err;
+	} else {
+		pdata->baud = 9600;
+		pdata->parity = 'n';
+		pdata->bits = 8;
+	}
+
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!res)
 		return -ENODEV;
-- 
2.25.1