linux-kernel - [PATCH v2 1/2] serial: sprd: getting port index via serial alias only

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Date:   Wed, 18 Mar 2020 16:31:19 +0800
From:   Chunyan Zhang <zhang.lyra@...il.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jiri Slaby <jslaby@...e.com>
Cc:     linux-serial@...r.kernel.org, linux-kernel@...r.kernel.org,
        Orson Zhai <orsonzhai@...il.com>,
        Baolin Wang <baolin.wang7@...il.com>,
        Chunyan Zhang <zhang.lyra@...il.com>,
        Chunyan Zhang <chunyan.zhang@...soc.com>
Subject: [PATCH v2 1/2] serial: sprd: getting port index via serial alias only

From: Chunyan Zhang <chunyan.zhang@...soc.com>

This patch simplifies the process of getting serial port number, with
this patch, serial devices must have alias 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 alias is mandatory.

Signed-off-by: Chunyan Zhang <chunyan.zhang@...soc.com>
---
 drivers/tty/serial/sprd_serial.c | 36 +++++---------------------------
 1 file changed, 5 insertions(+), 31 deletions(-)

diff --git a/drivers/tty/serial/sprd_serial.c b/drivers/tty/serial/sprd_serial.c
index 914862844790..9f8c14ff6454 100644
--- 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);
@@ -1204,14 +1181,11 @@ 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 index;
+	}
 
 	sprd_port[index] = devm_kzalloc(&pdev->dev, sizeof(*sprd_port[index]),
 					GFP_KERNEL);
-- 
2.20.1