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463 lines
11 KiB
463 lines
11 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* LED pattern trigger |
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* |
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* Idea discussed with Pavel Machek. Raphael Teysseyre implemented |
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* the first version, Baolin Wang simplified and improved the approach. |
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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/module.h> |
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#include <linux/mutex.h> |
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#include <linux/slab.h> |
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#include <linux/timer.h> |
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#define MAX_PATTERNS 1024 |
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/* |
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* When doing gradual dimming, the led brightness will be updated |
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* every 50 milliseconds. |
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*/ |
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#define UPDATE_INTERVAL 50 |
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struct pattern_trig_data { |
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struct led_classdev *led_cdev; |
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struct led_pattern patterns[MAX_PATTERNS]; |
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struct led_pattern *curr; |
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struct led_pattern *next; |
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struct mutex lock; |
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u32 npatterns; |
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int repeat; |
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int last_repeat; |
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int delta_t; |
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bool is_indefinite; |
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bool is_hw_pattern; |
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struct timer_list timer; |
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}; |
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static void pattern_trig_update_patterns(struct pattern_trig_data *data) |
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{ |
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data->curr = data->next; |
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if (!data->is_indefinite && data->curr == data->patterns) |
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data->repeat--; |
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if (data->next == data->patterns + data->npatterns - 1) |
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data->next = data->patterns; |
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else |
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data->next++; |
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data->delta_t = 0; |
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} |
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static int pattern_trig_compute_brightness(struct pattern_trig_data *data) |
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{ |
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int step_brightness; |
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/* |
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* If current tuple's duration is less than the dimming interval, |
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* we should treat it as a step change of brightness instead of |
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* doing gradual dimming. |
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*/ |
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if (data->delta_t == 0 || data->curr->delta_t < UPDATE_INTERVAL) |
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return data->curr->brightness; |
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step_brightness = abs(data->next->brightness - data->curr->brightness); |
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step_brightness = data->delta_t * step_brightness / data->curr->delta_t; |
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if (data->next->brightness > data->curr->brightness) |
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return data->curr->brightness + step_brightness; |
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else |
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return data->curr->brightness - step_brightness; |
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} |
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static void pattern_trig_timer_function(struct timer_list *t) |
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{ |
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struct pattern_trig_data *data = from_timer(data, t, timer); |
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for (;;) { |
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if (!data->is_indefinite && !data->repeat) |
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break; |
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if (data->curr->brightness == data->next->brightness) { |
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/* Step change of brightness */ |
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led_set_brightness(data->led_cdev, |
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data->curr->brightness); |
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mod_timer(&data->timer, |
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jiffies + msecs_to_jiffies(data->curr->delta_t)); |
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if (!data->next->delta_t) { |
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/* Skip the tuple with zero duration */ |
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pattern_trig_update_patterns(data); |
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} |
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/* Select next tuple */ |
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pattern_trig_update_patterns(data); |
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} else { |
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/* Gradual dimming */ |
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/* |
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* If the accumulation time is larger than current |
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* tuple's duration, we should go next one and re-check |
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* if we repeated done. |
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*/ |
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if (data->delta_t > data->curr->delta_t) { |
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pattern_trig_update_patterns(data); |
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continue; |
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} |
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led_set_brightness(data->led_cdev, |
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pattern_trig_compute_brightness(data)); |
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mod_timer(&data->timer, |
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jiffies + msecs_to_jiffies(UPDATE_INTERVAL)); |
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/* Accumulate the gradual dimming time */ |
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data->delta_t += UPDATE_INTERVAL; |
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} |
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break; |
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} |
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} |
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static int pattern_trig_start_pattern(struct led_classdev *led_cdev) |
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{ |
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struct pattern_trig_data *data = led_cdev->trigger_data; |
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if (!data->npatterns) |
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return 0; |
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if (data->is_hw_pattern) { |
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return led_cdev->pattern_set(led_cdev, data->patterns, |
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data->npatterns, data->repeat); |
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} |
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/* At least 2 tuples for software pattern. */ |
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if (data->npatterns < 2) |
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return -EINVAL; |
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data->delta_t = 0; |
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data->curr = data->patterns; |
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data->next = data->patterns + 1; |
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data->timer.expires = jiffies; |
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add_timer(&data->timer); |
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return 0; |
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} |
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static ssize_t repeat_show(struct device *dev, struct device_attribute *attr, |
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char *buf) |
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{ |
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struct led_classdev *led_cdev = dev_get_drvdata(dev); |
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struct pattern_trig_data *data = led_cdev->trigger_data; |
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int repeat; |
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mutex_lock(&data->lock); |
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repeat = data->last_repeat; |
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mutex_unlock(&data->lock); |
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return scnprintf(buf, PAGE_SIZE, "%d\n", repeat); |
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} |
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static ssize_t repeat_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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struct led_classdev *led_cdev = dev_get_drvdata(dev); |
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struct pattern_trig_data *data = led_cdev->trigger_data; |
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int err, res; |
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err = kstrtos32(buf, 10, &res); |
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if (err) |
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return err; |
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/* Number 0 and negative numbers except -1 are invalid. */ |
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if (res < -1 || res == 0) |
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return -EINVAL; |
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mutex_lock(&data->lock); |
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del_timer_sync(&data->timer); |
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if (data->is_hw_pattern) |
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led_cdev->pattern_clear(led_cdev); |
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data->last_repeat = data->repeat = res; |
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/* -1 means repeat indefinitely */ |
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if (data->repeat == -1) |
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data->is_indefinite = true; |
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else |
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data->is_indefinite = false; |
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err = pattern_trig_start_pattern(led_cdev); |
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mutex_unlock(&data->lock); |
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return err < 0 ? err : count; |
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} |
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static DEVICE_ATTR_RW(repeat); |
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static ssize_t pattern_trig_show_patterns(struct pattern_trig_data *data, |
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char *buf, bool hw_pattern) |
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{ |
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ssize_t count = 0; |
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int i; |
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mutex_lock(&data->lock); |
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if (!data->npatterns || (data->is_hw_pattern ^ hw_pattern)) |
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goto out; |
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for (i = 0; i < data->npatterns; i++) { |
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count += scnprintf(buf + count, PAGE_SIZE - count, |
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"%d %u ", |
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data->patterns[i].brightness, |
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data->patterns[i].delta_t); |
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} |
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buf[count - 1] = '\n'; |
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out: |
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mutex_unlock(&data->lock); |
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return count; |
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} |
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static int pattern_trig_store_patterns_string(struct pattern_trig_data *data, |
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const char *buf, size_t count) |
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{ |
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int ccount, cr, offset = 0; |
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while (offset < count - 1 && data->npatterns < MAX_PATTERNS) { |
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cr = 0; |
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ccount = sscanf(buf + offset, "%u %u %n", |
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&data->patterns[data->npatterns].brightness, |
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&data->patterns[data->npatterns].delta_t, &cr); |
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if (ccount != 2 || |
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data->patterns[data->npatterns].brightness > data->led_cdev->max_brightness) { |
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data->npatterns = 0; |
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return -EINVAL; |
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} |
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offset += cr; |
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data->npatterns++; |
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} |
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return 0; |
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} |
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static int pattern_trig_store_patterns_int(struct pattern_trig_data *data, |
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const u32 *buf, size_t count) |
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{ |
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unsigned int i; |
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for (i = 0; i < count; i += 2) { |
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data->patterns[data->npatterns].brightness = buf[i]; |
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data->patterns[data->npatterns].delta_t = buf[i + 1]; |
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data->npatterns++; |
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} |
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return 0; |
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} |
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static ssize_t pattern_trig_store_patterns(struct led_classdev *led_cdev, |
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const char *buf, const u32 *buf_int, |
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size_t count, bool hw_pattern) |
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{ |
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struct pattern_trig_data *data = led_cdev->trigger_data; |
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int err = 0; |
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mutex_lock(&data->lock); |
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del_timer_sync(&data->timer); |
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if (data->is_hw_pattern) |
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led_cdev->pattern_clear(led_cdev); |
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data->is_hw_pattern = hw_pattern; |
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data->npatterns = 0; |
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if (buf) |
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err = pattern_trig_store_patterns_string(data, buf, count); |
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else |
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err = pattern_trig_store_patterns_int(data, buf_int, count); |
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if (err) |
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goto out; |
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err = pattern_trig_start_pattern(led_cdev); |
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if (err) |
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data->npatterns = 0; |
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out: |
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mutex_unlock(&data->lock); |
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return err < 0 ? err : count; |
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} |
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static ssize_t pattern_show(struct device *dev, struct device_attribute *attr, |
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char *buf) |
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{ |
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struct led_classdev *led_cdev = dev_get_drvdata(dev); |
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struct pattern_trig_data *data = led_cdev->trigger_data; |
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return pattern_trig_show_patterns(data, buf, false); |
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} |
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static ssize_t pattern_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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struct led_classdev *led_cdev = dev_get_drvdata(dev); |
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return pattern_trig_store_patterns(led_cdev, buf, NULL, count, false); |
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} |
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static DEVICE_ATTR_RW(pattern); |
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static ssize_t hw_pattern_show(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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struct led_classdev *led_cdev = dev_get_drvdata(dev); |
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struct pattern_trig_data *data = led_cdev->trigger_data; |
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return pattern_trig_show_patterns(data, buf, true); |
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} |
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static ssize_t hw_pattern_store(struct device *dev, |
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struct device_attribute *attr, |
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const char *buf, size_t count) |
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{ |
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struct led_classdev *led_cdev = dev_get_drvdata(dev); |
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return pattern_trig_store_patterns(led_cdev, buf, NULL, count, true); |
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} |
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static DEVICE_ATTR_RW(hw_pattern); |
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static umode_t pattern_trig_attrs_mode(struct kobject *kobj, |
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struct attribute *attr, int index) |
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{ |
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struct device *dev = container_of(kobj, struct device, kobj); |
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struct led_classdev *led_cdev = dev_get_drvdata(dev); |
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if (attr == &dev_attr_repeat.attr || attr == &dev_attr_pattern.attr) |
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return attr->mode; |
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else if (attr == &dev_attr_hw_pattern.attr && led_cdev->pattern_set) |
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return attr->mode; |
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return 0; |
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} |
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static struct attribute *pattern_trig_attrs[] = { |
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&dev_attr_pattern.attr, |
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&dev_attr_hw_pattern.attr, |
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&dev_attr_repeat.attr, |
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NULL |
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}; |
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static const struct attribute_group pattern_trig_group = { |
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.attrs = pattern_trig_attrs, |
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.is_visible = pattern_trig_attrs_mode, |
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}; |
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static const struct attribute_group *pattern_trig_groups[] = { |
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&pattern_trig_group, |
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NULL, |
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}; |
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static void pattern_init(struct led_classdev *led_cdev) |
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{ |
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unsigned int size = 0; |
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u32 *pattern; |
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int err; |
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pattern = led_get_default_pattern(led_cdev, &size); |
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if (!pattern) |
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return; |
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if (size % 2) { |
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dev_warn(led_cdev->dev, "Expected pattern of tuples\n"); |
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goto out; |
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} |
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err = pattern_trig_store_patterns(led_cdev, NULL, pattern, size, false); |
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if (err < 0) |
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dev_warn(led_cdev->dev, |
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"Pattern initialization failed with error %d\n", err); |
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out: |
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kfree(pattern); |
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} |
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static int pattern_trig_activate(struct led_classdev *led_cdev) |
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{ |
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struct pattern_trig_data *data; |
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data = kzalloc(sizeof(*data), GFP_KERNEL); |
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if (!data) |
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return -ENOMEM; |
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if (!!led_cdev->pattern_set ^ !!led_cdev->pattern_clear) { |
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dev_warn(led_cdev->dev, |
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"Hardware pattern ops validation failed\n"); |
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led_cdev->pattern_set = NULL; |
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led_cdev->pattern_clear = NULL; |
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} |
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data->is_indefinite = true; |
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data->last_repeat = -1; |
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mutex_init(&data->lock); |
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data->led_cdev = led_cdev; |
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led_set_trigger_data(led_cdev, data); |
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timer_setup(&data->timer, pattern_trig_timer_function, 0); |
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led_cdev->activated = true; |
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if (led_cdev->flags & LED_INIT_DEFAULT_TRIGGER) { |
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pattern_init(led_cdev); |
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/* |
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* Mark as initialized even on pattern_init() error because |
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* any consecutive call to it would produce the same error. |
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*/ |
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led_cdev->flags &= ~LED_INIT_DEFAULT_TRIGGER; |
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} |
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return 0; |
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} |
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static void pattern_trig_deactivate(struct led_classdev *led_cdev) |
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{ |
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struct pattern_trig_data *data = led_cdev->trigger_data; |
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if (!led_cdev->activated) |
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return; |
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if (led_cdev->pattern_clear) |
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led_cdev->pattern_clear(led_cdev); |
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del_timer_sync(&data->timer); |
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led_set_brightness(led_cdev, LED_OFF); |
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kfree(data); |
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led_cdev->activated = false; |
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} |
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static struct led_trigger pattern_led_trigger = { |
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.name = "pattern", |
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.activate = pattern_trig_activate, |
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.deactivate = pattern_trig_deactivate, |
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.groups = pattern_trig_groups, |
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}; |
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static int __init pattern_trig_init(void) |
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{ |
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return led_trigger_register(&pattern_led_trigger); |
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} |
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static void __exit pattern_trig_exit(void) |
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{ |
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led_trigger_unregister(&pattern_led_trigger); |
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} |
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module_init(pattern_trig_init); |
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module_exit(pattern_trig_exit); |
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MODULE_AUTHOR("Raphael Teysseyre <[email protected]>"); |
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MODULE_AUTHOR("Baolin Wang <[email protected]>"); |
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MODULE_DESCRIPTION("LED Pattern trigger"); |
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MODULE_LICENSE("GPL v2");
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