linux/drivers/gpio/gpiolib-devprop.c
Thor Thayer 5a195c6d4e gpio: gpiolib-devprop: Check chip->parent pointer before dereferencing
Confirm the chip->parent is valid before dereferencing because
the parent parameter is optional.

Signed-off-by: Thor Thayer <tthayer@opensource.altera.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2016-10-25 20:23:19 +02:00

67 lines
1.7 KiB
C

/*
* Device property helpers for GPIO chips.
*
* Copyright (C) 2016, Intel Corporation
* Author: Mika Westerberg <mika.westerberg@linux.intel.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/property.h>
#include <linux/slab.h>
#include <linux/gpio/consumer.h>
#include <linux/gpio/driver.h>
#include "gpiolib.h"
/**
* devprop_gpiochip_set_names - Set GPIO line names using device properties
* @chip: GPIO chip whose lines should be named, if possible
*
* Looks for device property "gpio-line-names" and if it exists assigns
* GPIO line names for the chip. The memory allocated for the assigned
* names belong to the underlying firmware node and should not be released
* by the caller.
*/
void devprop_gpiochip_set_names(struct gpio_chip *chip)
{
struct gpio_device *gdev = chip->gpiodev;
const char **names;
int ret, i;
if (!chip->parent) {
dev_warn(&gdev->dev, "GPIO chip parent is NULL\n");
return;
}
ret = device_property_read_string_array(chip->parent, "gpio-line-names",
NULL, 0);
if (ret < 0)
return;
if (ret != gdev->ngpio) {
dev_warn(chip->parent,
"names %d do not match number of GPIOs %d\n", ret,
gdev->ngpio);
return;
}
names = kcalloc(gdev->ngpio, sizeof(*names), GFP_KERNEL);
if (!names)
return;
ret = device_property_read_string_array(chip->parent, "gpio-line-names",
names, gdev->ngpio);
if (ret < 0) {
dev_warn(chip->parent, "failed to read GPIO line names\n");
kfree(names);
return;
}
for (i = 0; i < gdev->ngpio; i++)
gdev->descs[i].name = names[i];
kfree(names);
}