drivers/gpio/gpiolib-devprop.c

   1 /*
   2  * Device property helpers for GPIO chips.
   3  *
   4  * Copyright (C) 2016, Intel Corporation
   5  * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/property.h>
  13 #include <linux/slab.h>
  14 #include <linux/gpio/consumer.h>
  15 #include <linux/gpio/driver.h>
  16
  17 #include "gpiolib.h"
  18
  19 /**
  20  * devprop_gpiochip_set_names - Set GPIO line names using device properties
  21  * @chip: GPIO chip whose lines should be named, if possible
  22  *
  23  * Looks for device property "gpio-line-names" and if it exists assigns
  24  * GPIO line names for the chip. The memory allocated for the assigned
  25  * names belong to the underlying firmware node and should not be released
  26  * by the caller.
  27  */
  28 void devprop_gpiochip_set_names(struct gpio_chip *chip)
  29 {
  30         struct gpio_device *gdev = chip->gpiodev;
  31         const char **names;
  32         int ret, i;
  33
  34         if (!chip->parent) {
  35                 dev_warn(&gdev->dev, "GPIO chip parent is NULL\n");
  36                 return;
  37         }
  38
  39         ret = device_property_read_string_array(chip->parent, "gpio-line-names",
  40                                                 NULL, 0);
  41         if (ret < 0)
  42                 return;
  43
  44         if (ret != gdev->ngpio) {
  45                 dev_warn(chip->parent,
  46                          "names %d do not match number of GPIOs %d\n", ret,
  47                          gdev->ngpio);
  48                 return;
  49         }
  50
  51         names = kcalloc(gdev->ngpio, sizeof(*names), GFP_KERNEL);
  52         if (!names)
  53                 return;
  54
  55         ret = device_property_read_string_array(chip->parent, "gpio-line-names",
  56                                                 names, gdev->ngpio);
  57         if (ret < 0) {
  58                 dev_warn(chip->parent, "failed to read GPIO line names\n");
  59                 kfree(names);
  60                 return;
  61         }
  62
  63         for (i = 0; i < gdev->ngpio; i++)
  64                 gdev->descs[i].name = names[i];
  65
  66         kfree(names);
  67 }