linux-kernel - [PATCH] tty: serial: meson: Fixed an issue where pclk was turned on on probe but should be turned off on subsequent errors.

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Message-ID: <20220301053738.21163-1-yu.tu@amlogic.com>
Date:   Tue, 1 Mar 2022 13:37:38 +0800
From:   Yu Tu <yu.tu@...ogic.com>
To:     <linux-serial@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-amlogic@...ts.infradead.org>, <linux-kernel@...r.kernel.org>
CC:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jiri Slaby <jirislaby@...nel.org>,
        Neil Armstrong <narmstrong@...libre.com>,
        Kevin Hilman <khilman@...libre.com>,
        Jerome Brunet <jbrunet@...libre.com>,
        Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
        Yu Tu <yu.tu@...ogic.com>, kernel test robot <lkp@...el.com>,
        Dan Carpenter <dan.carpenter@...cle.com>
Subject: [PATCH] tty: serial: meson: Fixed an issue where pclk was turned on on probe but should be turned off on subsequent errors.

Call clk_prepare_enable in the probe function to enable pclk. If you
exit the probe function later in an error, call clk_disable_unprepare
to disable pclk.

Fixes: 44023b8e1f14 ("tty: serial:meson: Describes the calculation of the UART baud rate clock using a clock frame“)
Reported-by: kernel test robot <lkp@...el.com>
Reported-by: Dan Carpenter <dan.carpenter@...cle.com>
Signed-off-by: Yu Tu <yu.tu@...ogic.com>
---
 drivers/tty/serial/meson_uart.c | 37 +++++++++++++++++++++++----------
 1 file changed, 26 insertions(+), 11 deletions(-)

diff --git a/drivers/tty/serial/meson_uart.c b/drivers/tty/serial/meson_uart.c
index bf6be5468aaf..972f210f3492 100644
--- a/drivers/tty/serial/meson_uart.c
+++ b/drivers/tty/serial/meson_uart.c
@@ -780,28 +780,37 @@ static int meson_uart_probe(struct platform_device *pdev)
 		return ret;
 
 	irq = platform_get_irq(pdev, 0);
-	if (irq < 0)
-		return irq;
+	if (irq < 0) {
+		ret = irq;
+		goto err_out_clk_disable;
+	}
 
 	of_property_read_u32(pdev->dev.of_node, "fifo-size", &fifosize);
 
 	if (meson_ports[pdev->id]) {
 		dev_err(&pdev->dev, "port %d already allocated\n", pdev->id);
-		return -EBUSY;
+		ret = -EBUSY;
+		goto err_out_clk_disable;
 	}
 
 	port = devm_kzalloc(&pdev->dev, sizeof(struct uart_port), GFP_KERNEL);
-	if (!port)
-		return -ENOMEM;
+	if (!port) {
+		ret = -ENOMEM;
+		goto err_out_clk_disable;
+	}
 
 	port->membase = devm_ioremap_resource(&pdev->dev, res_mem);
-	if (IS_ERR(port->membase))
-		return PTR_ERR(port->membase);
+	if (IS_ERR(port->membase)) {
+		ret = PTR_ERR(port->membase);
+		goto err_out_clk_disable;
+	}
 
 	private_data = devm_kzalloc(&pdev->dev, sizeof(*private_data),
 				    GFP_KERNEL);
-	if (!private_data)
-		return -ENOMEM;
+	if (!private_data) {
+		ret = -ENOMEM;
+		goto err_out_clk_disable;
+	}
 
 	if (device_get_match_data(&pdev->dev))
 		private_data->use_xtal_clk = true;
@@ -822,7 +831,7 @@ static int meson_uart_probe(struct platform_device *pdev)
 
 	ret = meson_uart_probe_clocks(port);
 	if (ret)
-		return ret;
+		goto err_out_clk_disable;
 
 	meson_ports[pdev->id] = port;
 	platform_set_drvdata(pdev, port);
@@ -831,9 +840,15 @@ static int meson_uart_probe(struct platform_device *pdev)
 	meson_uart_reset(port);
 
 	ret = uart_add_one_port(&meson_uart_driver, port);
-	if (ret)
+	if (ret) {
 		meson_ports[pdev->id] = NULL;
+		goto err_out_clk_disable;
+	}
+
+	return 0;
 
+err_out_clk_disable:
+	clk_disable_unprepare(pclk);
 	return ret;
 }
 

base-commit: d4ab5487cc77a4053dc9070c5761ad94bf397825
-- 
2.33.1