linux/drivers/leds/leds-pca9633.c

/*
 * Copyright 2011 bct electronic GmbH
 *
 * Author: Peter Meerwald <p.meerwald@bct-electronic.com>
 *
 * Based on leds-pca955x.c
 *
 * This file is subject to the terms and conditions of version 2 of
 * the GNU General Public License.  See the file COPYING in the main
 * directory of this archive for more details.
 *
 * LED driver for the PCA9633 I2C LED driver (7-bit slave address 0x62)
 *
 */

#include <linux/module.h>
#include <linux/delay.h>
#include <linux/string.h>
#include <linux/ctype.h>
#include <linux/leds.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/workqueue.h>
#include <linux/slab.h>

/* LED select registers determine the source that drives LED outputs */
#define PCA9633_LED_OFF		0x0	/* LED driver off */
#define PCA9633_LED_ON		0x1	/* LED driver on */
#define PCA9633_LED_PWM		0x2	/* Controlled through PWM */
#define PCA9633_LED_GRP_PWM	0x3	/* Controlled through PWM/GRPPWM */

#define PCA9633_MODE1		0x00
#define PCA9633_MODE2		0x01
#define PCA9633_PWM_BASE	0x02
#define PCA9633_LEDOUT		0x08

static const struct i2c_device_id pca9633_id[] = {
	{ "pca9633", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, pca9633_id);

struct pca9633_led {
	struct i2c_client *client;
	struct work_struct work;
	enum led_brightness brightness;
	struct led_classdev led_cdev;
	int led_num; /* 0 .. 3 potentially */
	char name[32];
};

static void pca9633_led_work(struct work_struct *work)
{
	struct pca9633_led *pca9633 = container_of(work,
		struct pca9633_led, work);
	u8 ledout = i2c_smbus_read_byte_data(pca9633->client, PCA9633_LEDOUT);
	int shift = 2 * pca9633->led_num;
	u8 mask = 0x3 << shift;

	switch (pca9633->brightness) {
	case LED_FULL:
		i2c_smbus_write_byte_data(pca9633->client, PCA9633_LEDOUT,
			(ledout & ~mask) | (PCA9633_LED_ON << shift));
		break;
	case LED_OFF:
		i2c_smbus_write_byte_data(pca9633->client, PCA9633_LEDOUT,
			ledout & ~mask);
		break;
	default:
		i2c_smbus_write_byte_data(pca9633->client,
			PCA9633_PWM_BASE + pca9633->led_num,
			pca9633->brightness);
		i2c_smbus_write_byte_data(pca9633->client, PCA9633_LEDOUT,
			(ledout & ~mask) | (PCA9633_LED_PWM << shift));
		break;
	}
}

static void pca9633_led_set(struct led_classdev *led_cdev,
	enum led_brightness value)
{
	struct pca9633_led *pca9633;

	pca9633 = container_of(led_cdev, struct pca9633_led, led_cdev);

	pca9633->brightness = value;

	/*
	 * Must use workqueue for the actual I/O since I2C operations
	 * can sleep.
	 */
	schedule_work(&pca9633->work);
}

static int __devinit pca9633_probe(struct i2c_client *client,
					const struct i2c_device_id *id)
{
	struct pca9633_led *pca9633;
	struct led_platform_data *pdata;
	int i, err;

	pdata = client->dev.platform_data;

	if (pdata) {
		if (pdata->num_leds <= 0 || pdata->num_leds > 4) {
			dev_err(&client->dev, "board info must claim at most 4 LEDs");
			return -EINVAL;
		}
	}

	pca9633 = kcalloc(4, sizeof(*pca9633), GFP_KERNEL);
	if (!pca9633)
		return -ENOMEM;

	i2c_set_clientdata(client, pca9633);

	for (i = 0; i < 4; i++) {
		pca9633[i].client = client;
		pca9633[i].led_num = i;

		/* Platform data can specify LED names and default triggers */
		if (pdata && i < pdata->num_leds) {
			if (pdata->leds[i].name)
				snprintf(pca9633[i].name,
					 sizeof(pca9633[i].name), "pca9633:%s",
					 pdata->leds[i].name);
			if (pdata->leds[i].default_trigger)
				pca9633[i].led_cdev.default_trigger =
					pdata->leds[i].default_trigger;
		} else {
			snprintf(pca9633[i].name, sizeof(pca9633[i].name),
				 "pca9633:%d", i);
		}

		pca9633[i].led_cdev.name = pca9633[i].name;
		pca9633[i].led_cdev.brightness_set = pca9633_led_set;

		INIT_WORK(&pca9633[i].work, pca9633_led_work);

		err = led_classdev_register(&client->dev, &pca9633[i].led_cdev);
		if (err < 0)
			goto exit;
	}

	/* Disable LED all-call address and set normal mode */
	i2c_smbus_write_byte_data(client, PCA9633_MODE1, 0x00);

	/* Turn off LEDs */
	i2c_smbus_write_byte_data(client, PCA9633_LEDOUT, 0x00);

	return 0;

exit:
	while (i--) {
		led_classdev_unregister(&pca9633[i].led_cdev);
		cancel_work_sync(&pca9633[i].work);
	}

	kfree(pca9633);

	return err;
}

static int __devexit pca9633_remove(struct i2c_client *client)
{
	struct pca9633_led *pca9633 = i2c_get_clientdata(client);
	int i;

	for (i = 0; i < 4; i++) {
		led_classdev_unregister(&pca9633[i].led_cdev);
		cancel_work_sync(&pca9633[i].work);
	}

	kfree(pca9633);

	return 0;
}

static struct i2c_driver pca9633_driver = {
	.driver = {
		.name	= "leds-pca9633",
		.owner	= THIS_MODULE,
	},
	.probe	= pca9633_probe,
	.remove	= __devexit_p(pca9633_remove),
	.id_table = pca9633_id,
};

module_i2c_driver(pca9633_driver);

MODULE_AUTHOR("Peter Meerwald <p.meerwald@bct-electronic.com>");
MODULE_DESCRIPTION("PCA9633 LED driver");
MODULE_LICENSE("GPL v2");