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22720a87d0
led_trigger_blink() calls led_blink_set() from a RCU read-side critical section so led_blink_set() must not sleep. Note sleeping was not allowed before the switch to RCU either because a spinlock was held before. led_blink_set() does not sleep when sw-blinking is used, but many LED controller drivers with hw blink support have a blink_set function which may sleep, leading to an oops like this one: [ 832.605062] ------------[ cut here ]------------ [ 832.605085] Voluntary context switch within RCU read-side critical section! [ 832.605119] WARNING: CPU: 2 PID: 370 at kernel/rcu/tree_plugin.h:318 rcu_note_context_switch+0x4ee/0x690 <snip> [ 832.606453] Call Trace: [ 832.606466] <TASK> [ 832.606487] __schedule+0x9f/0x1480 [ 832.606527] schedule+0x5d/0xe0 [ 832.606549] schedule_timeout+0x79/0x140 [ 832.606572] ? __pfx_process_timeout+0x10/0x10 [ 832.606599] wait_for_completion_timeout+0x6f/0x140 [ 832.606627] i2c_dw_xfer+0x101/0x460 [ 832.606659] ? psi_group_change+0x168/0x400 [ 832.606680] __i2c_transfer+0x172/0x6d0 [ 832.606709] i2c_smbus_xfer_emulated+0x27d/0x9c0 [ 832.606732] ? __schedule+0x430/0x1480 [ 832.606753] ? preempt_count_add+0x6a/0xa0 [ 832.606778] ? get_nohz_timer_target+0x18/0x190 [ 832.606796] ? lock_timer_base+0x61/0x80 [ 832.606817] ? preempt_count_add+0x6a/0xa0 [ 832.606842] __i2c_smbus_xfer+0xa2/0x3f0 [ 832.606862] i2c_smbus_xfer+0x66/0xf0 [ 832.606882] i2c_smbus_read_byte_data+0x41/0x70 [ 832.606901] ? _raw_spin_unlock_irqrestore+0x23/0x40 [ 832.606922] ? __pm_runtime_suspend+0x46/0xc0 [ 832.606946] cht_wc_byte_reg_read+0x2e/0x60 [ 832.606972] _regmap_read+0x5c/0x120 [ 832.606997] _regmap_update_bits+0x96/0xc0 [ 832.607023] regmap_update_bits_base+0x5b/0x90 [ 832.607053] cht_wc_leds_brightness_get+0x412/0x910 [leds_cht_wcove] [ 832.607094] led_blink_setup+0x28/0x100 [ 832.607119] led_trigger_blink+0x40/0x70 [ 832.607145] power_supply_update_leds+0x1b7/0x1c0 [ 832.607174] power_supply_changed_work+0x67/0xe0 [ 832.607198] process_one_work+0x1c8/0x3c0 [ 832.607222] worker_thread+0x4d/0x380 [ 832.607243] ? __pfx_worker_thread+0x10/0x10 [ 832.607258] kthread+0xe9/0x110 [ 832.607279] ? __pfx_kthread+0x10/0x10 [ 832.607300] ret_from_fork+0x2c/0x50 [ 832.607337] </TASK> [ 832.607344] ---[ end trace 0000000000000000 ]--- Add a new led_blink_set_nosleep() function which defers the actual led_blink_set() call to a workqueue when necessary to fix this. This also fixes an existing race where a pending led_set_brightness() has been deferred to set_brightness_work and might then race with a later led_cdev->blink_set() call. Note this race is only an issue with triggers mixing led_trigger_event() and led_trigger_blink() calls, sysfs API calls and led_trigger_blink_oneshot() are not affected. Note rather then adding a separate blink_set_blocking callback this uses the presence of the already existing brightness_set_blocking callback to detect if the blinking call should be deferred to set_brightness_work. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Reviewed-by: Jacek Anaszewski <jacek.anaszewski@gmail.com> Tested-by: Yauhen Kharuzhy <jekhor@gmail.com> Link: https://lore.kernel.org/r/20230510162234.291439-4-hdegoede@redhat.com Signed-off-by: Lee Jones <lee@kernel.org>
550 lines
15 KiB
C
550 lines
15 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* LED Class Core
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*
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* Copyright 2005-2006 Openedhand Ltd.
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*
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* Author: Richard Purdie <rpurdie@openedhand.com>
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*/
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#include <linux/kernel.h>
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#include <linux/leds.h>
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#include <linux/list.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/of.h>
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#include <linux/property.h>
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#include <linux/rwsem.h>
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#include <linux/slab.h>
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#include <uapi/linux/uleds.h>
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#include "leds.h"
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DECLARE_RWSEM(leds_list_lock);
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EXPORT_SYMBOL_GPL(leds_list_lock);
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LIST_HEAD(leds_list);
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EXPORT_SYMBOL_GPL(leds_list);
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const char * const led_colors[LED_COLOR_ID_MAX] = {
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[LED_COLOR_ID_WHITE] = "white",
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[LED_COLOR_ID_RED] = "red",
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[LED_COLOR_ID_GREEN] = "green",
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[LED_COLOR_ID_BLUE] = "blue",
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[LED_COLOR_ID_AMBER] = "amber",
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[LED_COLOR_ID_VIOLET] = "violet",
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[LED_COLOR_ID_YELLOW] = "yellow",
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[LED_COLOR_ID_IR] = "ir",
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[LED_COLOR_ID_MULTI] = "multicolor",
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[LED_COLOR_ID_RGB] = "rgb",
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};
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EXPORT_SYMBOL_GPL(led_colors);
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static int __led_set_brightness(struct led_classdev *led_cdev, unsigned int value)
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{
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if (!led_cdev->brightness_set)
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return -ENOTSUPP;
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led_cdev->brightness_set(led_cdev, value);
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return 0;
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}
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static int __led_set_brightness_blocking(struct led_classdev *led_cdev, unsigned int value)
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{
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if (!led_cdev->brightness_set_blocking)
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return -ENOTSUPP;
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return led_cdev->brightness_set_blocking(led_cdev, value);
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}
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static void led_timer_function(struct timer_list *t)
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{
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struct led_classdev *led_cdev = from_timer(led_cdev, t, blink_timer);
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unsigned long brightness;
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unsigned long delay;
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if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) {
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led_set_brightness_nosleep(led_cdev, LED_OFF);
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clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
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return;
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}
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if (test_and_clear_bit(LED_BLINK_ONESHOT_STOP,
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&led_cdev->work_flags)) {
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clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
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return;
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}
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brightness = led_get_brightness(led_cdev);
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if (!brightness) {
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/* Time to switch the LED on. */
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if (test_and_clear_bit(LED_BLINK_BRIGHTNESS_CHANGE,
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&led_cdev->work_flags))
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brightness = led_cdev->new_blink_brightness;
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else
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brightness = led_cdev->blink_brightness;
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delay = led_cdev->blink_delay_on;
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} else {
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/* Store the current brightness value to be able
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* to restore it when the delay_off period is over.
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*/
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led_cdev->blink_brightness = brightness;
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brightness = LED_OFF;
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delay = led_cdev->blink_delay_off;
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}
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led_set_brightness_nosleep(led_cdev, brightness);
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/* Return in next iteration if led is in one-shot mode and we are in
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* the final blink state so that the led is toggled each delay_on +
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* delay_off milliseconds in worst case.
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*/
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if (test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags)) {
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if (test_bit(LED_BLINK_INVERT, &led_cdev->work_flags)) {
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if (brightness)
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set_bit(LED_BLINK_ONESHOT_STOP,
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&led_cdev->work_flags);
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} else {
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if (!brightness)
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set_bit(LED_BLINK_ONESHOT_STOP,
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&led_cdev->work_flags);
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}
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}
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mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay));
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}
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static void set_brightness_delayed_set_brightness(struct led_classdev *led_cdev,
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unsigned int value)
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{
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int ret = 0;
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ret = __led_set_brightness(led_cdev, value);
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if (ret == -ENOTSUPP)
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ret = __led_set_brightness_blocking(led_cdev, value);
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if (ret < 0 &&
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/* LED HW might have been unplugged, therefore don't warn */
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!(ret == -ENODEV && (led_cdev->flags & LED_UNREGISTERING) &&
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(led_cdev->flags & LED_HW_PLUGGABLE)))
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dev_err(led_cdev->dev,
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"Setting an LED's brightness failed (%d)\n", ret);
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}
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static void set_brightness_delayed(struct work_struct *ws)
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{
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struct led_classdev *led_cdev =
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container_of(ws, struct led_classdev, set_brightness_work);
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if (test_and_clear_bit(LED_BLINK_DISABLE, &led_cdev->work_flags)) {
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led_stop_software_blink(led_cdev);
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set_bit(LED_SET_BRIGHTNESS_OFF, &led_cdev->work_flags);
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}
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/*
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* Triggers may call led_set_brightness(LED_OFF),
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* led_set_brightness(LED_FULL) in quick succession to disable blinking
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* and turn the LED on. Both actions may have been scheduled to run
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* before this work item runs once. To make sure this works properly
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* handle LED_SET_BRIGHTNESS_OFF first.
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*/
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if (test_and_clear_bit(LED_SET_BRIGHTNESS_OFF, &led_cdev->work_flags))
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set_brightness_delayed_set_brightness(led_cdev, LED_OFF);
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if (test_and_clear_bit(LED_SET_BRIGHTNESS, &led_cdev->work_flags))
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set_brightness_delayed_set_brightness(led_cdev, led_cdev->delayed_set_value);
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if (test_and_clear_bit(LED_SET_BLINK, &led_cdev->work_flags)) {
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unsigned long delay_on = led_cdev->delayed_delay_on;
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unsigned long delay_off = led_cdev->delayed_delay_off;
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led_blink_set(led_cdev, &delay_on, &delay_off);
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}
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}
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static void led_set_software_blink(struct led_classdev *led_cdev,
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unsigned long delay_on,
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unsigned long delay_off)
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{
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int current_brightness;
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current_brightness = led_get_brightness(led_cdev);
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if (current_brightness)
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led_cdev->blink_brightness = current_brightness;
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if (!led_cdev->blink_brightness)
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led_cdev->blink_brightness = led_cdev->max_brightness;
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led_cdev->blink_delay_on = delay_on;
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led_cdev->blink_delay_off = delay_off;
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/* never on - just set to off */
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if (!delay_on) {
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led_set_brightness_nosleep(led_cdev, LED_OFF);
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return;
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}
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/* never off - just set to brightness */
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if (!delay_off) {
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led_set_brightness_nosleep(led_cdev,
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led_cdev->blink_brightness);
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return;
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}
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set_bit(LED_BLINK_SW, &led_cdev->work_flags);
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mod_timer(&led_cdev->blink_timer, jiffies + 1);
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}
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static void led_blink_setup(struct led_classdev *led_cdev,
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unsigned long *delay_on,
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unsigned long *delay_off)
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{
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if (!test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags) &&
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led_cdev->blink_set &&
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!led_cdev->blink_set(led_cdev, delay_on, delay_off))
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return;
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/* blink with 1 Hz as default if nothing specified */
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if (!*delay_on && !*delay_off)
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*delay_on = *delay_off = 500;
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led_set_software_blink(led_cdev, *delay_on, *delay_off);
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}
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void led_init_core(struct led_classdev *led_cdev)
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{
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INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed);
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timer_setup(&led_cdev->blink_timer, led_timer_function, 0);
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}
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EXPORT_SYMBOL_GPL(led_init_core);
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void led_blink_set(struct led_classdev *led_cdev,
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unsigned long *delay_on,
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unsigned long *delay_off)
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{
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del_timer_sync(&led_cdev->blink_timer);
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clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
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clear_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags);
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clear_bit(LED_BLINK_ONESHOT_STOP, &led_cdev->work_flags);
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led_blink_setup(led_cdev, delay_on, delay_off);
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}
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EXPORT_SYMBOL_GPL(led_blink_set);
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void led_blink_set_oneshot(struct led_classdev *led_cdev,
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unsigned long *delay_on,
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unsigned long *delay_off,
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int invert)
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{
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if (test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags) &&
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timer_pending(&led_cdev->blink_timer))
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return;
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set_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags);
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clear_bit(LED_BLINK_ONESHOT_STOP, &led_cdev->work_flags);
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if (invert)
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set_bit(LED_BLINK_INVERT, &led_cdev->work_flags);
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else
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clear_bit(LED_BLINK_INVERT, &led_cdev->work_flags);
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led_blink_setup(led_cdev, delay_on, delay_off);
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}
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EXPORT_SYMBOL_GPL(led_blink_set_oneshot);
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void led_blink_set_nosleep(struct led_classdev *led_cdev, unsigned long delay_on,
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unsigned long delay_off)
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{
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/* If necessary delegate to a work queue task. */
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if (led_cdev->blink_set && led_cdev->brightness_set_blocking) {
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led_cdev->delayed_delay_on = delay_on;
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led_cdev->delayed_delay_off = delay_off;
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set_bit(LED_SET_BLINK, &led_cdev->work_flags);
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schedule_work(&led_cdev->set_brightness_work);
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return;
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}
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led_blink_set(led_cdev, &delay_on, &delay_off);
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}
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EXPORT_SYMBOL_GPL(led_blink_set_nosleep);
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void led_stop_software_blink(struct led_classdev *led_cdev)
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{
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del_timer_sync(&led_cdev->blink_timer);
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led_cdev->blink_delay_on = 0;
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led_cdev->blink_delay_off = 0;
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clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
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}
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EXPORT_SYMBOL_GPL(led_stop_software_blink);
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void led_set_brightness(struct led_classdev *led_cdev, unsigned int brightness)
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{
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/*
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* If software blink is active, delay brightness setting
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* until the next timer tick.
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*/
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if (test_bit(LED_BLINK_SW, &led_cdev->work_flags)) {
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/*
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* If we need to disable soft blinking delegate this to the
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* work queue task to avoid problems in case we are called
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* from hard irq context.
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*/
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if (!brightness) {
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set_bit(LED_BLINK_DISABLE, &led_cdev->work_flags);
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schedule_work(&led_cdev->set_brightness_work);
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} else {
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set_bit(LED_BLINK_BRIGHTNESS_CHANGE,
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&led_cdev->work_flags);
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led_cdev->new_blink_brightness = brightness;
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}
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return;
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}
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led_set_brightness_nosleep(led_cdev, brightness);
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}
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EXPORT_SYMBOL_GPL(led_set_brightness);
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void led_set_brightness_nopm(struct led_classdev *led_cdev, unsigned int value)
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{
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/* Use brightness_set op if available, it is guaranteed not to sleep */
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if (!__led_set_brightness(led_cdev, value))
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return;
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/*
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* Brightness setting can sleep, delegate it to a work queue task.
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* value 0 / LED_OFF is special, since it also disables hw-blinking
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* (sw-blink disable is handled in led_set_brightness()).
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* To avoid a hw-blink-disable getting lost when a second brightness
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* change is done immediately afterwards (before the work runs),
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* it uses a separate work_flag.
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*/
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if (value) {
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led_cdev->delayed_set_value = value;
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set_bit(LED_SET_BRIGHTNESS, &led_cdev->work_flags);
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} else {
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clear_bit(LED_SET_BRIGHTNESS, &led_cdev->work_flags);
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clear_bit(LED_SET_BLINK, &led_cdev->work_flags);
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set_bit(LED_SET_BRIGHTNESS_OFF, &led_cdev->work_flags);
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}
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schedule_work(&led_cdev->set_brightness_work);
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}
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EXPORT_SYMBOL_GPL(led_set_brightness_nopm);
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void led_set_brightness_nosleep(struct led_classdev *led_cdev, unsigned int value)
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{
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led_cdev->brightness = min(value, led_cdev->max_brightness);
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if (led_cdev->flags & LED_SUSPENDED)
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return;
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led_set_brightness_nopm(led_cdev, led_cdev->brightness);
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}
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EXPORT_SYMBOL_GPL(led_set_brightness_nosleep);
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int led_set_brightness_sync(struct led_classdev *led_cdev, unsigned int value)
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{
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if (led_cdev->blink_delay_on || led_cdev->blink_delay_off)
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return -EBUSY;
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led_cdev->brightness = min(value, led_cdev->max_brightness);
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if (led_cdev->flags & LED_SUSPENDED)
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return 0;
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return __led_set_brightness_blocking(led_cdev, led_cdev->brightness);
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}
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EXPORT_SYMBOL_GPL(led_set_brightness_sync);
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int led_update_brightness(struct led_classdev *led_cdev)
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{
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int ret = 0;
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if (led_cdev->brightness_get) {
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ret = led_cdev->brightness_get(led_cdev);
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if (ret >= 0) {
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led_cdev->brightness = ret;
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return 0;
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}
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}
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return ret;
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}
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EXPORT_SYMBOL_GPL(led_update_brightness);
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u32 *led_get_default_pattern(struct led_classdev *led_cdev, unsigned int *size)
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{
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struct fwnode_handle *fwnode = led_cdev->dev->fwnode;
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u32 *pattern;
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int count;
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count = fwnode_property_count_u32(fwnode, "led-pattern");
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if (count < 0)
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return NULL;
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pattern = kcalloc(count, sizeof(*pattern), GFP_KERNEL);
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if (!pattern)
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return NULL;
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if (fwnode_property_read_u32_array(fwnode, "led-pattern", pattern, count)) {
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kfree(pattern);
|
|
return NULL;
|
|
}
|
|
|
|
*size = count;
|
|
|
|
return pattern;
|
|
}
|
|
EXPORT_SYMBOL_GPL(led_get_default_pattern);
|
|
|
|
/* Caller must ensure led_cdev->led_access held */
|
|
void led_sysfs_disable(struct led_classdev *led_cdev)
|
|
{
|
|
lockdep_assert_held(&led_cdev->led_access);
|
|
|
|
led_cdev->flags |= LED_SYSFS_DISABLE;
|
|
}
|
|
EXPORT_SYMBOL_GPL(led_sysfs_disable);
|
|
|
|
/* Caller must ensure led_cdev->led_access held */
|
|
void led_sysfs_enable(struct led_classdev *led_cdev)
|
|
{
|
|
lockdep_assert_held(&led_cdev->led_access);
|
|
|
|
led_cdev->flags &= ~LED_SYSFS_DISABLE;
|
|
}
|
|
EXPORT_SYMBOL_GPL(led_sysfs_enable);
|
|
|
|
static void led_parse_fwnode_props(struct device *dev,
|
|
struct fwnode_handle *fwnode,
|
|
struct led_properties *props)
|
|
{
|
|
int ret;
|
|
|
|
if (!fwnode)
|
|
return;
|
|
|
|
if (fwnode_property_present(fwnode, "label")) {
|
|
ret = fwnode_property_read_string(fwnode, "label", &props->label);
|
|
if (ret)
|
|
dev_err(dev, "Error parsing 'label' property (%d)\n", ret);
|
|
return;
|
|
}
|
|
|
|
if (fwnode_property_present(fwnode, "color")) {
|
|
ret = fwnode_property_read_u32(fwnode, "color", &props->color);
|
|
if (ret)
|
|
dev_err(dev, "Error parsing 'color' property (%d)\n", ret);
|
|
else if (props->color >= LED_COLOR_ID_MAX)
|
|
dev_err(dev, "LED color identifier out of range\n");
|
|
else
|
|
props->color_present = true;
|
|
}
|
|
|
|
|
|
if (!fwnode_property_present(fwnode, "function"))
|
|
return;
|
|
|
|
ret = fwnode_property_read_string(fwnode, "function", &props->function);
|
|
if (ret) {
|
|
dev_err(dev,
|
|
"Error parsing 'function' property (%d)\n",
|
|
ret);
|
|
}
|
|
|
|
if (!fwnode_property_present(fwnode, "function-enumerator"))
|
|
return;
|
|
|
|
ret = fwnode_property_read_u32(fwnode, "function-enumerator",
|
|
&props->func_enum);
|
|
if (ret) {
|
|
dev_err(dev,
|
|
"Error parsing 'function-enumerator' property (%d)\n",
|
|
ret);
|
|
} else {
|
|
props->func_enum_present = true;
|
|
}
|
|
}
|
|
|
|
int led_compose_name(struct device *dev, struct led_init_data *init_data,
|
|
char *led_classdev_name)
|
|
{
|
|
struct led_properties props = {};
|
|
struct fwnode_handle *fwnode = init_data->fwnode;
|
|
const char *devicename = init_data->devicename;
|
|
|
|
/* We want to label LEDs that can produce full range of colors
|
|
* as RGB, not multicolor */
|
|
BUG_ON(props.color == LED_COLOR_ID_MULTI);
|
|
|
|
if (!led_classdev_name)
|
|
return -EINVAL;
|
|
|
|
led_parse_fwnode_props(dev, fwnode, &props);
|
|
|
|
if (props.label) {
|
|
/*
|
|
* If init_data.devicename is NULL, then it indicates that
|
|
* DT label should be used as-is for LED class device name.
|
|
* Otherwise the label is prepended with devicename to compose
|
|
* the final LED class device name.
|
|
*/
|
|
if (!devicename) {
|
|
strscpy(led_classdev_name, props.label,
|
|
LED_MAX_NAME_SIZE);
|
|
} else {
|
|
snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s",
|
|
devicename, props.label);
|
|
}
|
|
} else if (props.function || props.color_present) {
|
|
char tmp_buf[LED_MAX_NAME_SIZE];
|
|
|
|
if (props.func_enum_present) {
|
|
snprintf(tmp_buf, LED_MAX_NAME_SIZE, "%s:%s-%d",
|
|
props.color_present ? led_colors[props.color] : "",
|
|
props.function ?: "", props.func_enum);
|
|
} else {
|
|
snprintf(tmp_buf, LED_MAX_NAME_SIZE, "%s:%s",
|
|
props.color_present ? led_colors[props.color] : "",
|
|
props.function ?: "");
|
|
}
|
|
if (init_data->devname_mandatory) {
|
|
snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s",
|
|
devicename, tmp_buf);
|
|
} else {
|
|
strscpy(led_classdev_name, tmp_buf, LED_MAX_NAME_SIZE);
|
|
|
|
}
|
|
} else if (init_data->default_label) {
|
|
if (!devicename) {
|
|
dev_err(dev, "Legacy LED naming requires devicename segment");
|
|
return -EINVAL;
|
|
}
|
|
snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s",
|
|
devicename, init_data->default_label);
|
|
} else if (is_of_node(fwnode)) {
|
|
strscpy(led_classdev_name, to_of_node(fwnode)->name,
|
|
LED_MAX_NAME_SIZE);
|
|
} else
|
|
return -EINVAL;
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(led_compose_name);
|
|
|
|
enum led_default_state led_init_default_state_get(struct fwnode_handle *fwnode)
|
|
{
|
|
const char *state = NULL;
|
|
|
|
if (!fwnode_property_read_string(fwnode, "default-state", &state)) {
|
|
if (!strcmp(state, "keep"))
|
|
return LEDS_DEFSTATE_KEEP;
|
|
if (!strcmp(state, "on"))
|
|
return LEDS_DEFSTATE_ON;
|
|
}
|
|
|
|
return LEDS_DEFSTATE_OFF;
|
|
}
|
|
EXPORT_SYMBOL_GPL(led_init_default_state_get);
|