serial: sprd: getting port index via serial aliases only

This patch simplifies the process of getting serial port number, with
this patch, serial devices must have aliases configured in devicetree.

The serial port searched out via sprd_port array maybe wrong if we don't
have serial alias defined in devicetree, and specify console with command
line, we would get the wrong port number if other serial ports probe
failed before console's. So using aliases is mandatory.

Reviewed-by: Baolin Wang <baolin.wang7@gmail.com>
Signed-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com>
Link: https://lore.kernel.org/r/20200318105049.19623-2-zhang.lyra@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/sprd_serial.c b/drivers/tty/serial/sprd_serial.c
index 509781ee26bf17741f4eec2704ec4401271f89ca..23baf8cf1a3b32b3a25b68c0015a093b610b717f 100644 (file)
--- a/drivers/tty/serial/sprd_serial.c
+++ b/drivers/tty/serial/sprd_serial.c
@@ -1102,29 +1102,6 @@ static struct uart_driver sprd_uart_driver = {
        .cons = SPRD_CONSOLE,
 };
 
-static int sprd_probe_dt_alias(int index, struct device *dev)
-{
-       struct device_node *np;
-       int ret = index;
-
-       if (!IS_ENABLED(CONFIG_OF))
-               return ret;
-
-       np = dev->of_node;
-       if (!np)
-               return ret;
-
-       ret = of_alias_get_id(np, "serial");
-       if (ret < 0)
-               ret = index;
-       else if (ret >= ARRAY_SIZE(sprd_port) || sprd_port[ret] != NULL) {
-               dev_warn(dev, "requested serial port %d not available.\n", ret);
-               ret = index;
-       }
-
-       return ret;
-}
-
 static int sprd_remove(struct platform_device *dev)
 {
        struct sprd_uart_port *sup = platform_get_drvdata(dev);
@@ -1203,14 +1180,11 @@ static int sprd_probe(struct platform_device *pdev)
        int index;
        int ret;
 
-       for (index = 0; index < ARRAY_SIZE(sprd_port); index++)
-               if (sprd_port[index] == NULL)
-                       break;
-
-       if (index == ARRAY_SIZE(sprd_port))
-               return -EBUSY;
-
-       index = sprd_probe_dt_alias(index, &pdev->dev);
+       index = of_alias_get_id(pdev->dev.of_node, "serial");
+       if (index < 0 || index >= ARRAY_SIZE(sprd_port)) {
+               dev_err(&pdev->dev, "got a wrong serial alias id %d\n", index);
+               return -EINVAL;
+       }
 
        sprd_port[index] = devm_kzalloc(&pdev->dev, sizeof(*sprd_port[index]),
                                        GFP_KERNEL);