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479da1f538
Add a way to lookup a backlight device based on its name. Will be used by a USB display gadget getting the name from configfs. Signed-off-by: Noralf Trønnes <noralf@tronnes.org> Reviewed-by: Sam Ravnborg <sam@ravnborg.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Acked-by: Jingoo Han <jingoohan1@gmail.com> Signed-off-by: Lee Jones <lee.jones@linaro.org>
730 lines
19 KiB
C
730 lines
19 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Backlight Lowlevel Control Abstraction
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*
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* Copyright (C) 2003,2004 Hewlett-Packard Company
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*
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/device.h>
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#include <linux/backlight.h>
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#include <linux/notifier.h>
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#include <linux/ctype.h>
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#include <linux/err.h>
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#include <linux/fb.h>
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#include <linux/slab.h>
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#ifdef CONFIG_PMAC_BACKLIGHT
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#include <asm/backlight.h>
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#endif
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static struct list_head backlight_dev_list;
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static struct mutex backlight_dev_list_mutex;
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static struct blocking_notifier_head backlight_notifier;
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static const char *const backlight_types[] = {
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[BACKLIGHT_RAW] = "raw",
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[BACKLIGHT_PLATFORM] = "platform",
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[BACKLIGHT_FIRMWARE] = "firmware",
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};
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static const char *const backlight_scale_types[] = {
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[BACKLIGHT_SCALE_UNKNOWN] = "unknown",
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[BACKLIGHT_SCALE_LINEAR] = "linear",
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[BACKLIGHT_SCALE_NON_LINEAR] = "non-linear",
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};
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#if defined(CONFIG_FB) || (defined(CONFIG_FB_MODULE) && \
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defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE))
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/* This callback gets called when something important happens inside a
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* framebuffer driver. We're looking if that important event is blanking,
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* and if it is and necessary, we're switching backlight power as well ...
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*/
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static int fb_notifier_callback(struct notifier_block *self,
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unsigned long event, void *data)
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{
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struct backlight_device *bd;
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struct fb_event *evdata = data;
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int node = evdata->info->node;
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int fb_blank = 0;
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/* If we aren't interested in this event, skip it immediately ... */
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if (event != FB_EVENT_BLANK)
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return 0;
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bd = container_of(self, struct backlight_device, fb_notif);
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mutex_lock(&bd->ops_lock);
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if (bd->ops)
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if (!bd->ops->check_fb ||
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bd->ops->check_fb(bd, evdata->info)) {
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fb_blank = *(int *)evdata->data;
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if (fb_blank == FB_BLANK_UNBLANK &&
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!bd->fb_bl_on[node]) {
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bd->fb_bl_on[node] = true;
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if (!bd->use_count++) {
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bd->props.state &= ~BL_CORE_FBBLANK;
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bd->props.fb_blank = FB_BLANK_UNBLANK;
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backlight_update_status(bd);
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}
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} else if (fb_blank != FB_BLANK_UNBLANK &&
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bd->fb_bl_on[node]) {
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bd->fb_bl_on[node] = false;
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if (!(--bd->use_count)) {
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bd->props.state |= BL_CORE_FBBLANK;
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bd->props.fb_blank = fb_blank;
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backlight_update_status(bd);
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}
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}
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}
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mutex_unlock(&bd->ops_lock);
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return 0;
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}
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static int backlight_register_fb(struct backlight_device *bd)
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{
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memset(&bd->fb_notif, 0, sizeof(bd->fb_notif));
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bd->fb_notif.notifier_call = fb_notifier_callback;
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return fb_register_client(&bd->fb_notif);
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}
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static void backlight_unregister_fb(struct backlight_device *bd)
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{
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fb_unregister_client(&bd->fb_notif);
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}
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#else
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static inline int backlight_register_fb(struct backlight_device *bd)
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{
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return 0;
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}
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static inline void backlight_unregister_fb(struct backlight_device *bd)
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{
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}
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#endif /* CONFIG_FB */
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static void backlight_generate_event(struct backlight_device *bd,
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enum backlight_update_reason reason)
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{
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char *envp[2];
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switch (reason) {
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case BACKLIGHT_UPDATE_SYSFS:
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envp[0] = "SOURCE=sysfs";
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break;
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case BACKLIGHT_UPDATE_HOTKEY:
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envp[0] = "SOURCE=hotkey";
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break;
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default:
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envp[0] = "SOURCE=unknown";
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break;
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}
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envp[1] = NULL;
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kobject_uevent_env(&bd->dev.kobj, KOBJ_CHANGE, envp);
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sysfs_notify(&bd->dev.kobj, NULL, "actual_brightness");
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}
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static ssize_t bl_power_show(struct device *dev, struct device_attribute *attr,
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char *buf)
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{
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struct backlight_device *bd = to_backlight_device(dev);
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return sprintf(buf, "%d\n", bd->props.power);
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}
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static ssize_t bl_power_store(struct device *dev, struct device_attribute *attr,
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const char *buf, size_t count)
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{
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int rc;
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struct backlight_device *bd = to_backlight_device(dev);
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unsigned long power, old_power;
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rc = kstrtoul(buf, 0, &power);
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if (rc)
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return rc;
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rc = -ENXIO;
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mutex_lock(&bd->ops_lock);
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if (bd->ops) {
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pr_debug("set power to %lu\n", power);
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if (bd->props.power != power) {
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old_power = bd->props.power;
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bd->props.power = power;
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rc = backlight_update_status(bd);
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if (rc)
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bd->props.power = old_power;
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else
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rc = count;
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} else {
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rc = count;
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}
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}
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mutex_unlock(&bd->ops_lock);
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return rc;
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}
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static DEVICE_ATTR_RW(bl_power);
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static ssize_t brightness_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct backlight_device *bd = to_backlight_device(dev);
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return sprintf(buf, "%d\n", bd->props.brightness);
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}
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int backlight_device_set_brightness(struct backlight_device *bd,
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unsigned long brightness)
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{
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int rc = -ENXIO;
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mutex_lock(&bd->ops_lock);
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if (bd->ops) {
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if (brightness > bd->props.max_brightness)
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rc = -EINVAL;
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else {
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pr_debug("set brightness to %lu\n", brightness);
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bd->props.brightness = brightness;
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rc = backlight_update_status(bd);
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}
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}
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mutex_unlock(&bd->ops_lock);
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backlight_generate_event(bd, BACKLIGHT_UPDATE_SYSFS);
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return rc;
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}
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EXPORT_SYMBOL(backlight_device_set_brightness);
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static ssize_t brightness_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t count)
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{
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int rc;
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struct backlight_device *bd = to_backlight_device(dev);
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unsigned long brightness;
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rc = kstrtoul(buf, 0, &brightness);
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if (rc)
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return rc;
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rc = backlight_device_set_brightness(bd, brightness);
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return rc ? rc : count;
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}
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static DEVICE_ATTR_RW(brightness);
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static ssize_t type_show(struct device *dev, struct device_attribute *attr,
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char *buf)
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{
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struct backlight_device *bd = to_backlight_device(dev);
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return sprintf(buf, "%s\n", backlight_types[bd->props.type]);
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}
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static DEVICE_ATTR_RO(type);
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static ssize_t max_brightness_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct backlight_device *bd = to_backlight_device(dev);
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return sprintf(buf, "%d\n", bd->props.max_brightness);
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}
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static DEVICE_ATTR_RO(max_brightness);
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static ssize_t actual_brightness_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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int rc = -ENXIO;
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struct backlight_device *bd = to_backlight_device(dev);
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mutex_lock(&bd->ops_lock);
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if (bd->ops && bd->ops->get_brightness)
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rc = sprintf(buf, "%d\n", bd->ops->get_brightness(bd));
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else
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rc = sprintf(buf, "%d\n", bd->props.brightness);
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mutex_unlock(&bd->ops_lock);
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return rc;
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}
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static DEVICE_ATTR_RO(actual_brightness);
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static ssize_t scale_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct backlight_device *bd = to_backlight_device(dev);
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if (WARN_ON(bd->props.scale > BACKLIGHT_SCALE_NON_LINEAR))
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return sprintf(buf, "unknown\n");
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return sprintf(buf, "%s\n", backlight_scale_types[bd->props.scale]);
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}
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static DEVICE_ATTR_RO(scale);
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static struct class *backlight_class;
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#ifdef CONFIG_PM_SLEEP
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static int backlight_suspend(struct device *dev)
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{
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struct backlight_device *bd = to_backlight_device(dev);
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mutex_lock(&bd->ops_lock);
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if (bd->ops && bd->ops->options & BL_CORE_SUSPENDRESUME) {
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bd->props.state |= BL_CORE_SUSPENDED;
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backlight_update_status(bd);
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}
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mutex_unlock(&bd->ops_lock);
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return 0;
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}
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static int backlight_resume(struct device *dev)
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{
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struct backlight_device *bd = to_backlight_device(dev);
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mutex_lock(&bd->ops_lock);
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if (bd->ops && bd->ops->options & BL_CORE_SUSPENDRESUME) {
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bd->props.state &= ~BL_CORE_SUSPENDED;
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backlight_update_status(bd);
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}
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mutex_unlock(&bd->ops_lock);
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return 0;
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}
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#endif
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static SIMPLE_DEV_PM_OPS(backlight_class_dev_pm_ops, backlight_suspend,
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backlight_resume);
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static void bl_device_release(struct device *dev)
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{
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struct backlight_device *bd = to_backlight_device(dev);
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kfree(bd);
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}
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static struct attribute *bl_device_attrs[] = {
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&dev_attr_bl_power.attr,
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&dev_attr_brightness.attr,
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&dev_attr_actual_brightness.attr,
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&dev_attr_max_brightness.attr,
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&dev_attr_scale.attr,
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&dev_attr_type.attr,
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NULL,
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};
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ATTRIBUTE_GROUPS(bl_device);
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/**
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* backlight_force_update - tell the backlight subsystem that hardware state
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* has changed
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* @bd: the backlight device to update
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*
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* Updates the internal state of the backlight in response to a hardware event,
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* and generate a uevent to notify userspace
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*/
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void backlight_force_update(struct backlight_device *bd,
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enum backlight_update_reason reason)
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{
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mutex_lock(&bd->ops_lock);
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if (bd->ops && bd->ops->get_brightness)
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bd->props.brightness = bd->ops->get_brightness(bd);
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mutex_unlock(&bd->ops_lock);
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backlight_generate_event(bd, reason);
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}
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EXPORT_SYMBOL(backlight_force_update);
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/**
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* backlight_device_register - create and register a new object of
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* backlight_device class.
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* @name: the name of the new object(must be the same as the name of the
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* respective framebuffer device).
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* @parent: a pointer to the parent device
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* @devdata: an optional pointer to be stored for private driver use. The
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* methods may retrieve it by using bl_get_data(bd).
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* @ops: the backlight operations structure.
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*
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* Creates and registers new backlight device. Returns either an
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* ERR_PTR() or a pointer to the newly allocated device.
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*/
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struct backlight_device *backlight_device_register(const char *name,
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struct device *parent, void *devdata, const struct backlight_ops *ops,
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const struct backlight_properties *props)
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{
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struct backlight_device *new_bd;
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int rc;
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pr_debug("backlight_device_register: name=%s\n", name);
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new_bd = kzalloc(sizeof(struct backlight_device), GFP_KERNEL);
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if (!new_bd)
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return ERR_PTR(-ENOMEM);
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mutex_init(&new_bd->update_lock);
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mutex_init(&new_bd->ops_lock);
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new_bd->dev.class = backlight_class;
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new_bd->dev.parent = parent;
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new_bd->dev.release = bl_device_release;
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dev_set_name(&new_bd->dev, "%s", name);
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dev_set_drvdata(&new_bd->dev, devdata);
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/* Set default properties */
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if (props) {
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memcpy(&new_bd->props, props,
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sizeof(struct backlight_properties));
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if (props->type <= 0 || props->type >= BACKLIGHT_TYPE_MAX) {
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WARN(1, "%s: invalid backlight type", name);
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new_bd->props.type = BACKLIGHT_RAW;
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}
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} else {
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new_bd->props.type = BACKLIGHT_RAW;
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}
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rc = device_register(&new_bd->dev);
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if (rc) {
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put_device(&new_bd->dev);
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return ERR_PTR(rc);
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}
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rc = backlight_register_fb(new_bd);
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if (rc) {
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device_unregister(&new_bd->dev);
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return ERR_PTR(rc);
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}
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new_bd->ops = ops;
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#ifdef CONFIG_PMAC_BACKLIGHT
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mutex_lock(&pmac_backlight_mutex);
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if (!pmac_backlight)
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pmac_backlight = new_bd;
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mutex_unlock(&pmac_backlight_mutex);
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#endif
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mutex_lock(&backlight_dev_list_mutex);
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list_add(&new_bd->entry, &backlight_dev_list);
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mutex_unlock(&backlight_dev_list_mutex);
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blocking_notifier_call_chain(&backlight_notifier,
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BACKLIGHT_REGISTERED, new_bd);
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return new_bd;
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}
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EXPORT_SYMBOL(backlight_device_register);
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struct backlight_device *backlight_device_get_by_type(enum backlight_type type)
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{
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bool found = false;
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struct backlight_device *bd;
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mutex_lock(&backlight_dev_list_mutex);
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list_for_each_entry(bd, &backlight_dev_list, entry) {
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if (bd->props.type == type) {
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found = true;
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break;
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}
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}
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mutex_unlock(&backlight_dev_list_mutex);
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return found ? bd : NULL;
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}
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EXPORT_SYMBOL(backlight_device_get_by_type);
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/**
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* backlight_device_get_by_name - Get backlight device by name
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* @name: Device name
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*
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* This function looks up a backlight device by its name. It obtains a reference
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* on the backlight device and it is the caller's responsibility to drop the
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* reference by calling backlight_put().
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*
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* Returns:
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* A pointer to the backlight device if found, otherwise NULL.
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*/
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struct backlight_device *backlight_device_get_by_name(const char *name)
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{
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struct device *dev;
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dev = class_find_device_by_name(backlight_class, name);
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return dev ? to_backlight_device(dev) : NULL;
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}
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EXPORT_SYMBOL(backlight_device_get_by_name);
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/**
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* backlight_device_unregister - unregisters a backlight device object.
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* @bd: the backlight device object to be unregistered and freed.
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*
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* Unregisters a previously registered via backlight_device_register object.
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*/
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void backlight_device_unregister(struct backlight_device *bd)
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{
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if (!bd)
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return;
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mutex_lock(&backlight_dev_list_mutex);
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list_del(&bd->entry);
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mutex_unlock(&backlight_dev_list_mutex);
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#ifdef CONFIG_PMAC_BACKLIGHT
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mutex_lock(&pmac_backlight_mutex);
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if (pmac_backlight == bd)
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pmac_backlight = NULL;
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mutex_unlock(&pmac_backlight_mutex);
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#endif
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blocking_notifier_call_chain(&backlight_notifier,
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BACKLIGHT_UNREGISTERED, bd);
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mutex_lock(&bd->ops_lock);
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bd->ops = NULL;
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mutex_unlock(&bd->ops_lock);
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backlight_unregister_fb(bd);
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device_unregister(&bd->dev);
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}
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EXPORT_SYMBOL(backlight_device_unregister);
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static void devm_backlight_device_release(struct device *dev, void *res)
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{
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struct backlight_device *backlight = *(struct backlight_device **)res;
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backlight_device_unregister(backlight);
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}
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static int devm_backlight_device_match(struct device *dev, void *res,
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void *data)
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{
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struct backlight_device **r = res;
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return *r == data;
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}
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/**
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* backlight_register_notifier - get notified of backlight (un)registration
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* @nb: notifier block with the notifier to call on backlight (un)registration
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*
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* @return 0 on success, otherwise a negative error code
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*
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* Register a notifier to get notified when backlight devices get registered
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* or unregistered.
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*/
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int backlight_register_notifier(struct notifier_block *nb)
|
|
{
|
|
return blocking_notifier_chain_register(&backlight_notifier, nb);
|
|
}
|
|
EXPORT_SYMBOL(backlight_register_notifier);
|
|
|
|
/**
|
|
* backlight_unregister_notifier - unregister a backlight notifier
|
|
* @nb: notifier block to unregister
|
|
*
|
|
* @return 0 on success, otherwise a negative error code
|
|
*
|
|
* Register a notifier to get notified when backlight devices get registered
|
|
* or unregistered.
|
|
*/
|
|
int backlight_unregister_notifier(struct notifier_block *nb)
|
|
{
|
|
return blocking_notifier_chain_unregister(&backlight_notifier, nb);
|
|
}
|
|
EXPORT_SYMBOL(backlight_unregister_notifier);
|
|
|
|
/**
|
|
* devm_backlight_device_register - resource managed backlight_device_register()
|
|
* @dev: the device to register
|
|
* @name: the name of the device
|
|
* @parent: a pointer to the parent device
|
|
* @devdata: an optional pointer to be stored for private driver use
|
|
* @ops: the backlight operations structure
|
|
* @props: the backlight properties
|
|
*
|
|
* @return a struct backlight on success, or an ERR_PTR on error
|
|
*
|
|
* Managed backlight_device_register(). The backlight_device returned
|
|
* from this function are automatically freed on driver detach.
|
|
* See backlight_device_register() for more information.
|
|
*/
|
|
struct backlight_device *devm_backlight_device_register(struct device *dev,
|
|
const char *name, struct device *parent, void *devdata,
|
|
const struct backlight_ops *ops,
|
|
const struct backlight_properties *props)
|
|
{
|
|
struct backlight_device **ptr, *backlight;
|
|
|
|
ptr = devres_alloc(devm_backlight_device_release, sizeof(*ptr),
|
|
GFP_KERNEL);
|
|
if (!ptr)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
backlight = backlight_device_register(name, parent, devdata, ops,
|
|
props);
|
|
if (!IS_ERR(backlight)) {
|
|
*ptr = backlight;
|
|
devres_add(dev, ptr);
|
|
} else {
|
|
devres_free(ptr);
|
|
}
|
|
|
|
return backlight;
|
|
}
|
|
EXPORT_SYMBOL(devm_backlight_device_register);
|
|
|
|
/**
|
|
* devm_backlight_device_unregister - resource managed backlight_device_unregister()
|
|
* @dev: the device to unregister
|
|
* @bd: the backlight device to unregister
|
|
*
|
|
* Deallocated a backlight allocated with devm_backlight_device_register().
|
|
* Normally this function will not need to be called and the resource management
|
|
* code will ensure that the resource is freed.
|
|
*/
|
|
void devm_backlight_device_unregister(struct device *dev,
|
|
struct backlight_device *bd)
|
|
{
|
|
int rc;
|
|
|
|
rc = devres_release(dev, devm_backlight_device_release,
|
|
devm_backlight_device_match, bd);
|
|
WARN_ON(rc);
|
|
}
|
|
EXPORT_SYMBOL(devm_backlight_device_unregister);
|
|
|
|
#ifdef CONFIG_OF
|
|
static int of_parent_match(struct device *dev, const void *data)
|
|
{
|
|
return dev->parent && dev->parent->of_node == data;
|
|
}
|
|
|
|
/**
|
|
* of_find_backlight_by_node() - find backlight device by device-tree node
|
|
* @node: device-tree node of the backlight device
|
|
*
|
|
* Returns a pointer to the backlight device corresponding to the given DT
|
|
* node or NULL if no such backlight device exists or if the device hasn't
|
|
* been probed yet.
|
|
*
|
|
* This function obtains a reference on the backlight device and it is the
|
|
* caller's responsibility to drop the reference by calling put_device() on
|
|
* the backlight device's .dev field.
|
|
*/
|
|
struct backlight_device *of_find_backlight_by_node(struct device_node *node)
|
|
{
|
|
struct device *dev;
|
|
|
|
dev = class_find_device(backlight_class, NULL, node, of_parent_match);
|
|
|
|
return dev ? to_backlight_device(dev) : NULL;
|
|
}
|
|
EXPORT_SYMBOL(of_find_backlight_by_node);
|
|
#endif
|
|
|
|
/**
|
|
* of_find_backlight - Get backlight device
|
|
* @dev: Device
|
|
*
|
|
* This function looks for a property named 'backlight' on the DT node
|
|
* connected to @dev and looks up the backlight device.
|
|
*
|
|
* Call backlight_put() to drop the reference on the backlight device.
|
|
*
|
|
* Returns:
|
|
* A pointer to the backlight device if found.
|
|
* Error pointer -EPROBE_DEFER if the DT property is set, but no backlight
|
|
* device is found.
|
|
* NULL if there's no backlight property.
|
|
*/
|
|
struct backlight_device *of_find_backlight(struct device *dev)
|
|
{
|
|
struct backlight_device *bd = NULL;
|
|
struct device_node *np;
|
|
|
|
if (!dev)
|
|
return NULL;
|
|
|
|
if (IS_ENABLED(CONFIG_OF) && dev->of_node) {
|
|
np = of_parse_phandle(dev->of_node, "backlight", 0);
|
|
if (np) {
|
|
bd = of_find_backlight_by_node(np);
|
|
of_node_put(np);
|
|
if (!bd)
|
|
return ERR_PTR(-EPROBE_DEFER);
|
|
/*
|
|
* Note: gpio_backlight uses brightness as
|
|
* power state during probe
|
|
*/
|
|
if (!bd->props.brightness)
|
|
bd->props.brightness = bd->props.max_brightness;
|
|
}
|
|
}
|
|
|
|
return bd;
|
|
}
|
|
EXPORT_SYMBOL(of_find_backlight);
|
|
|
|
static void devm_backlight_release(void *data)
|
|
{
|
|
backlight_put(data);
|
|
}
|
|
|
|
/**
|
|
* devm_of_find_backlight - Resource-managed of_find_backlight()
|
|
* @dev: Device
|
|
*
|
|
* Device managed version of of_find_backlight().
|
|
* The reference on the backlight device is automatically
|
|
* dropped on driver detach.
|
|
*/
|
|
struct backlight_device *devm_of_find_backlight(struct device *dev)
|
|
{
|
|
struct backlight_device *bd;
|
|
int ret;
|
|
|
|
bd = of_find_backlight(dev);
|
|
if (IS_ERR_OR_NULL(bd))
|
|
return bd;
|
|
ret = devm_add_action(dev, devm_backlight_release, bd);
|
|
if (ret) {
|
|
backlight_put(bd);
|
|
return ERR_PTR(ret);
|
|
}
|
|
return bd;
|
|
}
|
|
EXPORT_SYMBOL(devm_of_find_backlight);
|
|
|
|
static void __exit backlight_class_exit(void)
|
|
{
|
|
class_destroy(backlight_class);
|
|
}
|
|
|
|
static int __init backlight_class_init(void)
|
|
{
|
|
backlight_class = class_create(THIS_MODULE, "backlight");
|
|
if (IS_ERR(backlight_class)) {
|
|
pr_warn("Unable to create backlight class; errno = %ld\n",
|
|
PTR_ERR(backlight_class));
|
|
return PTR_ERR(backlight_class);
|
|
}
|
|
|
|
backlight_class->dev_groups = bl_device_groups;
|
|
backlight_class->pm = &backlight_class_dev_pm_ops;
|
|
INIT_LIST_HEAD(&backlight_dev_list);
|
|
mutex_init(&backlight_dev_list_mutex);
|
|
BLOCKING_INIT_NOTIFIER_HEAD(&backlight_notifier);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* if this is compiled into the kernel, we need to ensure that the
|
|
* class is registered before users of the class try to register lcd's
|
|
*/
|
|
postcore_initcall(backlight_class_init);
|
|
module_exit(backlight_class_exit);
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>");
|
|
MODULE_DESCRIPTION("Backlight Lowlevel Control Abstraction");
|