serial: 8250_dw: Move device tree code to separate function

Trivial cleanup. This makes it easier to add different
methods to enumerate the device, for example ACPI 5.0
enumeration.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Jamie Iles <jamie@jamieiles.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 47 insertions, 31 deletions

diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index e1749012e8e3..d96e02e25be4 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -87,25 +87,51 @@ static int dw8250_handle_irq(struct uart_port *p)
         return 0;
 }
 
+static int dw8250_probe_of(struct uart_port *p)
+{
+        struct device_node      *np = p->dev->of_node;
+        u32                     val;
+
+        if (!of_property_read_u32(np, "reg-io-width", &val)) {
+                switch (val) {
+                case 1:
+                        break;
+                case 4:
+                        p->iotype = UPIO_MEM32;
+                        p->serial_in = dw8250_serial_in32;
+                        p->serial_out = dw8250_serial_out32;
+                        break;
+                default:
+                        dev_err(p->dev, "unsupported reg-io-width (%u)\n", val);
+                        return -EINVAL;
+                }
+        }
+
+        if (!of_property_read_u32(np, "reg-shift", &val))
+                p->regshift = val;
+
+        if (of_property_read_u32(np, "clock-frequency", &val)) {
+                dev_err(p->dev, "no clock-frequency property set\n");
+                return -EINVAL;
+        }
+        p->uartclk = val;
+
+        return 0;
+}
+
 static int dw8250_probe(struct platform_device *pdev)
 {
         struct uart_8250_port uart = {};
         struct resource *regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
         struct resource *irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
-        struct device_node *np = pdev->dev.of_node;
-        u32 val;
         struct dw8250_data *data;
+        int err;
 
         if (!regs || !irq) {
                 dev_err(&pdev->dev, "no registers/irq defined\n");
                 return -EINVAL;
         }
 
-        data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
-        if (!data)
-                return -ENOMEM;
-        uart.port.private_data = data;
-
         spin_lock_init(&uart.port.lock);
         uart.port.mapbase = regs->start;
         uart.port.irq = irq->start;
@@ -121,30 +147,20 @@ static int dw8250_probe(struct platform_device *pdev)
         uart.port.iotype = UPIO_MEM;
         uart.port.serial_in = dw8250_serial_in;
         uart.port.serial_out = dw8250_serial_out;
-        if (!of_property_read_u32(np, "reg-io-width", &val)) {
-                switch (val) {
-                case 1:
-                        break;
-                case 4:
-                        uart.port.iotype = UPIO_MEM32;
-                        uart.port.serial_in = dw8250_serial_in32;
-                        uart.port.serial_out = dw8250_serial_out32;
-                        break;
-                default:
-                        dev_err(&pdev->dev, "unsupported reg-io-width (%u)\n",
-                                val);
-                        return -EINVAL;
-                }
+
+        if (pdev->dev.of_node) {
+                err = dw8250_probe_of(&uart.port);
+                if (err)
+                        return err;
+        } else {
+                return -ENODEV;
         }
 
-        if (!of_property_read_u32(np, "reg-shift", &val))
-                uart.port.regshift = val;
+        data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+        if (!data)
+                return -ENOMEM;
 
-        if (of_property_read_u32(np, "clock-frequency", &val)) {
-                dev_err(&pdev->dev, "no clock-frequency property set\n");
-                return -EINVAL;
-        }
-        uart.port.uartclk = val;
+        uart.port.private_data = data;
 
         data->line = serial8250_register_8250_port(&uart);
         if (data->line < 0)
@@ -187,17 +203,17 @@ static int dw8250_resume(struct platform_device *pdev)
 #define dw8250_resume NULL
 #endif /* CONFIG_PM */
 
-static const struct of_device_id dw8250_match[] = {
+static const struct of_device_id dw8250_of_match[] = {
         { .compatible = "snps,dw-apb-uart" },
         { /* Sentinel */ }
 };
-MODULE_DEVICE_TABLE(of, dw8250_match);
+MODULE_DEVICE_TABLE(of, dw8250_of_match);
 
 static struct platform_driver dw8250_platform_driver = {
         .driver = {
                 .name           = "dw-apb-uart",
                 .owner          = THIS_MODULE,
-                .of_match_table = dw8250_match,
+                .of_match_table = dw8250_of_match,
         },
         .probe                  = dw8250_probe,
         .remove                 = dw8250_remove,