git.ipfire.org Git - thirdparty/openwrt.git/blob

   1 From 1e0dc5254a44722653bef6041e7b4ddbd689aba6 Mon Sep 17 00:00:00 2001
   2 From: Dave Stevenson <dave.stevenson@raspberrypi.com>
   3 Date: Fri, 17 May 2024 17:35:25 +0100
   4 Subject: [PATCH 1102/1135] backlight: Add a display name to the core, and a
   5  function to set it
   6
   7 The naming of backlight devices is not terribly useful for
   8 associating a backlight controller with a display (assuming
   9 it is attached to one).
  10
  11 Add a sysfs node that will return a display name that can be set
  12 by other subsystems.
  13
  14 Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
  15 ---
  16  drivers/video/backlight/backlight.c | 21 +++++++++++++++++++++
  17  include/linux/backlight.h           | 15 +++++++++++++++
  18  2 files changed, 36 insertions(+)
  19
  20 --- a/drivers/video/backlight/backlight.c
  21 +++ b/drivers/video/backlight/backlight.c
  22 @@ -285,6 +285,15 @@ static ssize_t max_brightness_show(struc
  23  }
  24  static DEVICE_ATTR_RO(max_brightness);
  25
  26 +static ssize_t display_name_show(struct device *dev,
  27 +                                struct device_attribute *attr, char *buf)
  28 +{
  29 +       struct backlight_device *bd = to_backlight_device(dev);
  30 +
  31 +       return sprintf(buf, "%s\n", bd->props.display_name);
  32 +}
  33 +static DEVICE_ATTR_RO(display_name);
  34 +
  35  static ssize_t actual_brightness_show(struct device *dev,
  36                 struct device_attribute *attr, char *buf)
  37  {
  38 @@ -365,6 +374,7 @@ static struct attribute *bl_device_attrs
  39         &dev_attr_max_brightness.attr,
  40         &dev_attr_scale.attr,
  41         &dev_attr_type.attr,
  42 +       &dev_attr_display_name.attr,
  43         NULL,
  44  };
  45  ATTRIBUTE_GROUPS(bl_device);
  46 @@ -662,6 +672,17 @@ static int of_parent_match(struct device
  47         return dev->parent && dev->parent->of_node == data;
  48  }
  49
  50 +int backlight_set_display_name(struct backlight_device *bd, const char *name)
  51 +{
  52 +       if (!bd)
  53 +               return -EINVAL;
  54 +
  55 +       strscpy_pad(bd->props.display_name, name, sizeof(bd->props.display_name));
  56 +
  57 +       return 0;
  58 +}
  59 +EXPORT_SYMBOL(backlight_set_display_name);
  60 +
  61  /**
  62   * of_find_backlight_by_node() - find backlight device by device-tree node
  63   * @node: device-tree node of the backlight device
  64 --- a/include/linux/backlight.h
  65 +++ b/include/linux/backlight.h
  66 @@ -270,6 +270,13 @@ struct backlight_properties {
  67          * @scale: The type of the brightness scale.
  68          */
  69         enum backlight_scale scale;
  70 +
  71 +#define BL_DISPLAY_NAME_LEN 32
  72 +       /**
  73 +        * @display_name: Optional name that can be registered to associate a
  74 +        * backlight device with a display device.
  75 +        */
  76 +       char display_name[BL_DISPLAY_NAME_LEN];
  77  };
  78
  79  /**
  80 @@ -478,12 +485,20 @@ of_find_backlight_by_node(struct device_
  81
  82  #if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
  83  struct backlight_device *devm_of_find_backlight(struct device *dev);
  84 +int backlight_set_display_name(struct backlight_device *bd, const char *name);
  85  #else
  86  static inline struct backlight_device *
  87  devm_of_find_backlight(struct device *dev)
  88  {
  89         return NULL;
  90  }
  91 +
  92 +static inline int backlight_set_display_name(struct backlight_device *bd,
  93 +                                            const char *name)
  94 +{
  95 +       return 0;
  96 +}
  97 +
  98  #endif
  99
 100  #endif