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serial: 8250_dw: Add valid clk pointer check 

Commit ffc3ae6dd "serial: 8250_dw: Enable runtime PM" introduced runtime
PM management, which enables/disables the clk without checking if the clk
is valid. However, this driver allows to be probed without a defined clk,
using clock-frequency, as a fallback.

Therefore, on platforms that are device tree probed using clock-frequency
instead of clk, we get an ugly NULL pointer dereference.

This patch fixes it by simply adding a check before accessing the clk api.

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ezequiel Garcia 2013-05-07 08:27:16 -03:00 committed by Greg Kroah-Hartman
parent f722406faa
commit dbd2df859a
1 changed files with 4 additions and 2 deletions
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6
drivers/tty/serial/8250/8250_dw.c
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@ -338,7 +338,8 @@ static int dw8250_runtime_suspend(struct device *dev)
{
struct dw8250_data *data = dev_get_drvdata(dev);
clk_disable_unprepare(data->clk);
if (!IS_ERR(data->clk))
clk_disable_unprepare(data->clk);
return 0;
}
@ -347,7 +348,8 @@ static int dw8250_runtime_resume(struct device *dev)
{
struct dw8250_data *data = dev_get_drvdata(dev);
clk_prepare_enable(data->clk);
if (!IS_ERR(data->clk))
clk_prepare_enable(data->clk);
return 0;
}