leds-pca9633.c

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/*
 * Copyright 2011 bct electronic GmbH
 *
 * Author: Peter Meerwald <[email protected]>
 *
 * 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>
#include <linux/platform_data/leds-pca9633.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 pca9633_platform_data *pdata;
    int i, err;

    pdata = client->dev.platform_data;

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

    pca9633 = devm_kzalloc(&client->dev, 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->leds.num_leds) {
            if (pdata->leds.leds[i].name)
                snprintf(pca9633[i].name,
                     sizeof(pca9633[i].name), "pca9633:%s",
                     pdata->leds.leds[i].name);
            if (pdata->leds.leds[i].default_trigger)
                pca9633[i].led_cdev.default_trigger =
                    pdata->leds.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);

    /* Configure output: open-drain or totem pole (push-pull) */
    if (pdata && pdata->outdrv == PCA9633_OPEN_DRAIN)
        i2c_smbus_write_byte_data(client, PCA9633_MODE2, 0x01);

    /* 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);
    }

    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);
    }

    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 <[email protected]>");
MODULE_DESCRIPTION("PCA9633 LED driver");
MODULE_LICENSE("GPL v2");