Release 4.12 drivers/leds/leds-lt3593.c

/*
 * LEDs driver for LT3593 controllers
 *
 * See the datasheet at http://cds.linear.com/docs/Datasheet/3593f.pdf
 *
 * Copyright (c) 2009 Daniel Mack <daniel@caiaq.de>
 *
 * Based on leds-gpio.c,
 *
 *   Copyright (C) 2007 8D Technologies inc.
 *   Raphael Assenat <raph@8d.com>
 *   Copyright (C) 2008 Freescale Semiconductor, Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/leds.h>
#include <linux/delay.h>
#include <linux/gpio.h>
#include <linux/slab.h>
#include <linux/module.h>


struct lt3593_led_data {
	
struct led_classdev cdev;
	
unsigned gpio;
};



static int lt3593_led_set(struct led_classdev *led_cdev,
			   enum led_brightness value)
{
	struct lt3593_led_data *led_dat =
		container_of(led_cdev, struct lt3593_led_data, cdev);
	int pulses;

	/*
         * The LT3593 resets its internal current level register to the maximum
         * level on the first falling edge on the control pin. Each following
         * falling edge decreases the current level by 625uA. Up to 32 pulses
         * can be sent, so the maximum power reduction is 20mA.
         * After a timeout of 128us, the value is taken from the register and
         * applied is to the output driver.
         */

	if (value == 0) {
		gpio_set_value_cansleep(led_dat->gpio, 0);
		return 0;
	}

	pulses = 32 - (value * 32) / 255;

	if (pulses == 0) {
		gpio_set_value_cansleep(led_dat->gpio, 0);
		mdelay(1);
		gpio_set_value_cansleep(led_dat->gpio, 1);
		return 0;
	}

	gpio_set_value_cansleep(led_dat->gpio, 1);

	while (pulses--) {
		gpio_set_value_cansleep(led_dat->gpio, 0);
		udelay(1);
		gpio_set_value_cansleep(led_dat->gpio, 1);
		udelay(1);
	}

	return 0;
}

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Daniel Mack
123
83.67%
1
50.00%
Andrew Lunn
24
16.33%
1
50.00%
Total
147
100.00%
2
100.00%



static int create_lt3593_led(const struct gpio_led *template,
	struct lt3593_led_data *led_dat, struct device *parent)
{
	int ret, state;

	/* skip leds on GPIOs that aren't available */
	if (!gpio_is_valid(template->gpio)) {
		dev_info(parent, "%s: skipping unavailable LT3593 LED at gpio %d (%s)\n",
				KBUILD_MODNAME, template->gpio, template->name);
		return 0;
	}

	led_dat->cdev.name = template->name;
	led_dat->cdev.default_trigger = template->default_trigger;
	led_dat->gpio = template->gpio;

	led_dat->cdev.brightness_set_blocking = lt3593_led_set;

	state = (template->default_state == LEDS_GPIO_DEFSTATE_ON);
	led_dat->cdev.brightness = state ? LED_FULL : LED_OFF;

	if (!template->retain_state_suspended)
		led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;

	ret = devm_gpio_request_one(parent, template->gpio, state ?
				    GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW,
				    template->name);
	if (ret < 0)
		return ret;

	ret = led_classdev_register(parent, &led_dat->cdev);
	if (ret < 0)
		return ret;

	dev_info(parent, "%s: registered LT3593 LED '%s' at GPIO %d\n",
		KBUILD_MODNAME, template->name, template->gpio);

	return 0;
}

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Daniel Mack
179
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Jingoo Han
12
5.88%
2
33.33%
Sachin Kamat
12
5.88%
2
33.33%
Andrew Lunn
1
0.49%
1
16.67%
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204
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6
100.00%



static void delete_lt3593_led(struct lt3593_led_data *led)
{
	if (!gpio_is_valid(led->gpio))
		return;

	led_classdev_unregister(&led->cdev);
}

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static int lt3593_led_probe(struct platform_device *pdev)
{
	struct gpio_led_platform_data *pdata = dev_get_platdata(&pdev->dev);
	struct lt3593_led_data *leds_data;
	int i, ret = 0;

	if (!pdata)
		return -EBUSY;

	leds_data = devm_kzalloc(&pdev->dev,
			sizeof(struct lt3593_led_data) * pdata->num_leds,
			GFP_KERNEL);
	if (!leds_data)
		return -ENOMEM;

	for (i = 0; i < pdata->num_leds; i++) {
		ret = create_lt3593_led(&pdata->leds[i], &leds_data[i],
				      &pdev->dev);
		if (ret < 0)
			goto err;
	}

	platform_set_drvdata(pdev, leds_data);

	return 0;

err:
	for (i = i - 1; i >= 0; i--)
		delete_lt3593_led(&leds_data[i]);

	return ret;
}

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Daniel Mack
155
93.94%
1
33.33%
Bryan Wu
6
3.64%
1
33.33%
Jingoo Han
4
2.42%
1
33.33%
Total
165
100.00%
3
100.00%



static int lt3593_led_remove(struct platform_device *pdev)
{
	int i;
	struct gpio_led_platform_data *pdata = dev_get_platdata(&pdev->dev);
	struct lt3593_led_data *leds_data;

	leds_data = platform_get_drvdata(pdev);

	for (i = 0; i < pdata->num_leds; i++)
		delete_lt3593_led(&leds_data[i]);

	return 0;
}

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2
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static struct platform_driver lt3593_led_driver = {
	.probe		= lt3593_led_probe,
	.remove		= lt3593_led_remove,
	.driver		= {
		.name	= "leds-lt3593",
        },
};


module_platform_driver(lt3593_led_driver);

MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>");
MODULE_DESCRIPTION("LED driver for LT3593 controllers");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:leds-lt3593");
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623
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25
3.58%
1
9.09%
Jingoo Han
20
2.87%
3
27.27%
Sachin Kamat
12
1.72%
2
18.18%
Axel Lin
6
0.86%
1
9.09%
Bryan Wu
6
0.86%
1
9.09%
Paul Gortmaker
3
0.43%
1
9.09%
Tejun Heo
3
0.43%
1
9.09%
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11
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Directory: drivers/leds

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