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  * @fwnode: Property Node containing the gpio-line-names property
  23  *
  24  * Looks for device property "gpio-line-names" and if it exists assigns
  25  * GPIO line names for the chip. The memory allocated for the assigned
  26  * names belong to the underlying firmware node and should not be released
  27  * by the caller.
  28  */
  29 void devprop_gpiochip_set_names(struct gpio_chip *chip,
  30                                 const struct fwnode_handle *fwnode)
  31 {
  32         struct gpio_device *gdev = chip->gpiodev;
  33         const char **names;
  34         int ret, i;
  35
  36         ret = fwnode_property_read_string_array(fwnode, "gpio-line-names",
  37                                                 NULL, 0);
  38         if (ret < 0)
  39                 return;
  40
  41         if (ret != gdev->ngpio) {
  42                 dev_warn(&gdev->dev,
  43                          "names %d do not match number of GPIOs %d\n", ret,
  44                          gdev->ngpio);
  45                 return;
  46         }
  47
  48         names = kcalloc(gdev->ngpio, sizeof(*names), GFP_KERNEL);
  49         if (!names)
  50                 return;
  51
  52         ret = fwnode_property_read_string_array(fwnode, "gpio-line-names",
  53                                                 names, gdev->ngpio);
  54         if (ret < 0) {
  55                 dev_warn(&gdev->dev, "failed to read GPIO line names\n");
  56                 kfree(names);
  57                 return;
  58         }
  59
  60         for (i = 0; i < gdev->ngpio; i++)
  61                 gdev->descs[i].name = names[i];
  62
  63         kfree(names);
  64 }