1 | // SPDX-License-Identifier: GPL-2.0 |
2 | // |
3 | // LED Kernel Transient Trigger |
4 | // |
5 | // Transient trigger allows one shot timer activation. Please refer to |
6 | // Documentation/leds/ledtrig-transient.rst for details |
7 | // Copyright (C) 2012 Shuah Khan <shuahkhan@gmail.com> |
8 | // |
9 | // Based on Richard Purdie's ledtrig-timer.c and Atsushi Nemoto's |
10 | // ledtrig-heartbeat.c |
11 | // Design and use-case input from Jonas Bonn <jonas@southpole.se> and |
12 | // Neil Brown <neilb@suse.de> |
13 | |
14 | #include <linux/module.h> |
15 | #include <linux/kernel.h> |
16 | #include <linux/init.h> |
17 | #include <linux/device.h> |
18 | #include <linux/slab.h> |
19 | #include <linux/timer.h> |
20 | #include <linux/leds.h> |
21 | #include "../leds.h" |
22 | |
23 | struct transient_trig_data { |
24 | int activate; |
25 | int state; |
26 | int restore_state; |
27 | unsigned long duration; |
28 | struct timer_list timer; |
29 | struct led_classdev *led_cdev; |
30 | }; |
31 | |
32 | static void transient_timer_function(struct timer_list *t) |
33 | { |
34 | struct transient_trig_data *transient_data = |
35 | from_timer(transient_data, t, timer); |
36 | struct led_classdev *led_cdev = transient_data->led_cdev; |
37 | |
38 | transient_data->activate = 0; |
39 | led_set_brightness_nosleep(led_cdev, value: transient_data->restore_state); |
40 | } |
41 | |
42 | static ssize_t transient_activate_show(struct device *dev, |
43 | struct device_attribute *attr, char *buf) |
44 | { |
45 | struct transient_trig_data *transient_data = |
46 | led_trigger_get_drvdata(dev); |
47 | |
48 | return sprintf(buf, fmt: "%d\n" , transient_data->activate); |
49 | } |
50 | |
51 | static ssize_t transient_activate_store(struct device *dev, |
52 | struct device_attribute *attr, const char *buf, size_t size) |
53 | { |
54 | struct led_classdev *led_cdev = led_trigger_get_led(dev); |
55 | struct transient_trig_data *transient_data = |
56 | led_trigger_get_drvdata(dev); |
57 | unsigned long state; |
58 | ssize_t ret; |
59 | |
60 | ret = kstrtoul(s: buf, base: 10, res: &state); |
61 | if (ret) |
62 | return ret; |
63 | |
64 | if (state != 1 && state != 0) |
65 | return -EINVAL; |
66 | |
67 | /* cancel the running timer */ |
68 | if (state == 0 && transient_data->activate == 1) { |
69 | del_timer(timer: &transient_data->timer); |
70 | transient_data->activate = state; |
71 | led_set_brightness_nosleep(led_cdev, |
72 | value: transient_data->restore_state); |
73 | return size; |
74 | } |
75 | |
76 | /* start timer if there is no active timer */ |
77 | if (state == 1 && transient_data->activate == 0 && |
78 | transient_data->duration != 0) { |
79 | transient_data->activate = state; |
80 | led_set_brightness_nosleep(led_cdev, value: transient_data->state); |
81 | transient_data->restore_state = |
82 | (transient_data->state == LED_FULL) ? LED_OFF : LED_FULL; |
83 | mod_timer(timer: &transient_data->timer, |
84 | expires: jiffies + msecs_to_jiffies(m: transient_data->duration)); |
85 | } |
86 | |
87 | /* state == 0 && transient_data->activate == 0 |
88 | timer is not active - just return */ |
89 | /* state == 1 && transient_data->activate == 1 |
90 | timer is already active - just return */ |
91 | |
92 | return size; |
93 | } |
94 | |
95 | static ssize_t transient_duration_show(struct device *dev, |
96 | struct device_attribute *attr, char *buf) |
97 | { |
98 | struct transient_trig_data *transient_data = led_trigger_get_drvdata(dev); |
99 | |
100 | return sprintf(buf, fmt: "%lu\n" , transient_data->duration); |
101 | } |
102 | |
103 | static ssize_t transient_duration_store(struct device *dev, |
104 | struct device_attribute *attr, const char *buf, size_t size) |
105 | { |
106 | struct transient_trig_data *transient_data = |
107 | led_trigger_get_drvdata(dev); |
108 | unsigned long state; |
109 | ssize_t ret; |
110 | |
111 | ret = kstrtoul(s: buf, base: 10, res: &state); |
112 | if (ret) |
113 | return ret; |
114 | |
115 | transient_data->duration = state; |
116 | return size; |
117 | } |
118 | |
119 | static ssize_t transient_state_show(struct device *dev, |
120 | struct device_attribute *attr, char *buf) |
121 | { |
122 | struct transient_trig_data *transient_data = |
123 | led_trigger_get_drvdata(dev); |
124 | int state; |
125 | |
126 | state = (transient_data->state == LED_FULL) ? 1 : 0; |
127 | return sprintf(buf, fmt: "%d\n" , state); |
128 | } |
129 | |
130 | static ssize_t transient_state_store(struct device *dev, |
131 | struct device_attribute *attr, const char *buf, size_t size) |
132 | { |
133 | struct transient_trig_data *transient_data = |
134 | led_trigger_get_drvdata(dev); |
135 | unsigned long state; |
136 | ssize_t ret; |
137 | |
138 | ret = kstrtoul(s: buf, base: 10, res: &state); |
139 | if (ret) |
140 | return ret; |
141 | |
142 | if (state != 1 && state != 0) |
143 | return -EINVAL; |
144 | |
145 | transient_data->state = (state == 1) ? LED_FULL : LED_OFF; |
146 | return size; |
147 | } |
148 | |
149 | static DEVICE_ATTR(activate, 0644, transient_activate_show, |
150 | transient_activate_store); |
151 | static DEVICE_ATTR(duration, 0644, transient_duration_show, |
152 | transient_duration_store); |
153 | static DEVICE_ATTR(state, 0644, transient_state_show, transient_state_store); |
154 | |
155 | static struct attribute *transient_trig_attrs[] = { |
156 | &dev_attr_activate.attr, |
157 | &dev_attr_duration.attr, |
158 | &dev_attr_state.attr, |
159 | NULL |
160 | }; |
161 | ATTRIBUTE_GROUPS(transient_trig); |
162 | |
163 | static int transient_trig_activate(struct led_classdev *led_cdev) |
164 | { |
165 | struct transient_trig_data *tdata; |
166 | |
167 | tdata = kzalloc(size: sizeof(struct transient_trig_data), GFP_KERNEL); |
168 | if (!tdata) |
169 | return -ENOMEM; |
170 | |
171 | led_set_trigger_data(led_cdev, trigger_data: tdata); |
172 | tdata->led_cdev = led_cdev; |
173 | |
174 | timer_setup(&tdata->timer, transient_timer_function, 0); |
175 | |
176 | return 0; |
177 | } |
178 | |
179 | static void transient_trig_deactivate(struct led_classdev *led_cdev) |
180 | { |
181 | struct transient_trig_data *transient_data = led_get_trigger_data(led_cdev); |
182 | |
183 | timer_shutdown_sync(timer: &transient_data->timer); |
184 | led_set_brightness_nosleep(led_cdev, value: transient_data->restore_state); |
185 | kfree(objp: transient_data); |
186 | } |
187 | |
188 | static struct led_trigger transient_trigger = { |
189 | .name = "transient" , |
190 | .activate = transient_trig_activate, |
191 | .deactivate = transient_trig_deactivate, |
192 | .groups = transient_trig_groups, |
193 | }; |
194 | module_led_trigger(transient_trigger); |
195 | |
196 | MODULE_AUTHOR("Shuah Khan <shuahkhan@gmail.com>" ); |
197 | MODULE_DESCRIPTION("Transient LED trigger" ); |
198 | MODULE_LICENSE("GPL v2" ); |
199 | |