drivers/gpio/gpiolib-devprop.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Device property helpers for GPIO chips.
   4  *
   5  * Copyright (C) 2016, Intel Corporation
   6  * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
   7  */
   8
   9 #include <linux/property.h>
  10 #include <linux/slab.h>
  11 #include <linux/gpio/consumer.h>
  12 #include <linux/gpio/driver.h>
  13 #include <linux/export.h>
  14
  15 #include "gpiolib.h"
  16
  17 /**
  18  * devprop_gpiochip_set_names - Set GPIO line names using device properties
  19  * @chip: GPIO chip whose lines should be named, if possible
  20  * @fwnode: Property Node containing the gpio-line-names property
  21  *
  22  * Looks for device property "gpio-line-names" and if it exists assigns
  23  * GPIO line names for the chip. The memory allocated for the assigned
  24  * names belong to the underlying firmware node and should not be released
  25  * by the caller.
  26  */
  27 void devprop_gpiochip_set_names(struct gpio_chip *chip,
  28                                 const struct fwnode_handle *fwnode)
  29 {
  30         struct gpio_device *gdev = chip->gpiodev;
  31         const char **names;
  32         int ret, i;
  33         int count;
  34
  35         count = fwnode_property_read_string_array(fwnode, "gpio-line-names",
  36                                                   NULL, 0);
  37         if (count < 0)
  38                 return;
  39
  40         if (count > gdev->ngpio) {
  41                 dev_warn(&gdev->dev, "gpio-line-names is length %d but should be at most length %d",
  42                          count, gdev->ngpio);
  43                 count = gdev->ngpio;
  44         }
  45
  46         names = kcalloc(count, sizeof(*names), GFP_KERNEL);
  47         if (!names)
  48                 return;
  49
  50         ret = fwnode_property_read_string_array(fwnode, "gpio-line-names",
  51                                                 names, count);
  52         if (ret < 0) {
  53                 dev_warn(&gdev->dev, "failed to read GPIO line names\n");
  54                 kfree(names);
  55                 return;
  56         }
  57
  58         for (i = 0; i < count; i++)
  59                 gdev->descs[i].name = names[i];
  60
  61         kfree(names);
  62 }
  63 EXPORT_SYMBOL_GPL(devprop_gpiochip_set_names);