leds-ns2.c

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/*
 * leds-ns2.c - Driver for the Network Space v2 (and parents) dual-GPIO LED
 *
 * Copyright (C) 2010 LaCie
 *
 * Author: Simon Guinot <[email protected]>
 *
 * Based on leds-gpio.c by Raphael Assenat <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/gpio.h>
#include <linux/leds.h>
#include <linux/module.h>
#include <linux/platform_data/leds-kirkwood-ns2.h>

/*
 * The Network Space v2 dual-GPIO LED is wired to a CPLD and can blink in
 * relation with the SATA activity. This capability is exposed through the
 * "sata" sysfs attribute.
 *
 * The following array detail the different LED registers and the combination
 * of their possible values:
 *
 *  cmd_led   |  slow_led  | /SATA active | LED state
 *            |            |              |
 *     1      |     0      |      x       |  off
 *     -      |     1      |      x       |  on
 *     0      |     0      |      1       |  on
 *     0      |     0      |      0       |  blink (rate 300ms)
 */

enum ns2_led_modes {
    NS_V2_LED_OFF,
    NS_V2_LED_ON,
    NS_V2_LED_SATA,
};

struct ns2_led_mode_value {
    enum ns2_led_modes  mode;
    int         cmd_level;
    int         slow_level;
};

static struct ns2_led_mode_value ns2_led_modval[] = {
    { NS_V2_LED_OFF , 1, 0 },
    { NS_V2_LED_ON  , 0, 1 },
    { NS_V2_LED_ON  , 1, 1 },
    { NS_V2_LED_SATA, 0, 0 },
};

struct ns2_led_data {
    struct led_classdev cdev;
    unsigned        cmd;
    unsigned        slow;
    unsigned char       sata; /* True when SATA mode active. */
    rwlock_t        rw_lock; /* Lock GPIOs. */
};

static int ns2_led_get_mode(struct ns2_led_data *led_dat,
                enum ns2_led_modes *mode)
{
    int i;
    int ret = -EINVAL;
    int cmd_level;
    int slow_level;

    read_lock_irq(&led_dat->rw_lock);

    cmd_level = gpio_get_value(led_dat->cmd);
    slow_level = gpio_get_value(led_dat->slow);

    for (i = 0; i < ARRAY_SIZE(ns2_led_modval); i++) {
        if (cmd_level == ns2_led_modval[i].cmd_level &&
            slow_level == ns2_led_modval[i].slow_level) {
            *mode = ns2_led_modval[i].mode;
            ret = 0;
            break;
        }
    }

    read_unlock_irq(&led_dat->rw_lock);

    return ret;
}

static void ns2_led_set_mode(struct ns2_led_data *led_dat,
                 enum ns2_led_modes mode)
{
    int i;
    unsigned long flags;

    write_lock_irqsave(&led_dat->rw_lock, flags);

    for (i = 0; i < ARRAY_SIZE(ns2_led_modval); i++) {
        if (mode == ns2_led_modval[i].mode) {
            gpio_set_value(led_dat->cmd,
                       ns2_led_modval[i].cmd_level);
            gpio_set_value(led_dat->slow,
                       ns2_led_modval[i].slow_level);
        }
    }

    write_unlock_irqrestore(&led_dat->rw_lock, flags);
}

static void ns2_led_set(struct led_classdev *led_cdev,
            enum led_brightness value)
{
    struct ns2_led_data *led_dat =
        container_of(led_cdev, struct ns2_led_data, cdev);
    enum ns2_led_modes mode;

    if (value == LED_OFF)
        mode = NS_V2_LED_OFF;
    else if (led_dat->sata)
        mode = NS_V2_LED_SATA;
    else
        mode = NS_V2_LED_ON;

    ns2_led_set_mode(led_dat, mode);
}

static ssize_t ns2_led_sata_store(struct device *dev,
                  struct device_attribute *attr,
                  const char *buff, size_t count)
{
    struct led_classdev *led_cdev = dev_get_drvdata(dev);
    struct ns2_led_data *led_dat =
        container_of(led_cdev, struct ns2_led_data, cdev);
    int ret;
    unsigned long enable;
    enum ns2_led_modes mode;

    ret = strict_strtoul(buff, 10, &enable);
    if (ret < 0)
        return ret;

    enable = !!enable;

    if (led_dat->sata == enable)
        return count;

    ret = ns2_led_get_mode(led_dat, &mode);
    if (ret < 0)
        return ret;

    if (enable && mode == NS_V2_LED_ON)
        ns2_led_set_mode(led_dat, NS_V2_LED_SATA);
    if (!enable && mode == NS_V2_LED_SATA)
        ns2_led_set_mode(led_dat, NS_V2_LED_ON);

    led_dat->sata = enable;

    return count;
}

static ssize_t ns2_led_sata_show(struct device *dev,
                 struct device_attribute *attr, char *buf)
{
    struct led_classdev *led_cdev = dev_get_drvdata(dev);
    struct ns2_led_data *led_dat =
        container_of(led_cdev, struct ns2_led_data, cdev);

    return sprintf(buf, "%d\n", led_dat->sata);
}

static DEVICE_ATTR(sata, 0644, ns2_led_sata_show, ns2_led_sata_store);

static int __devinit
create_ns2_led(struct platform_device *pdev, struct ns2_led_data *led_dat,
           const struct ns2_led *template)
{
    int ret;
    enum ns2_led_modes mode;

    ret = gpio_request(template->cmd, template->name);
    if (ret == 0) {
        ret = gpio_direction_output(template->cmd,
                        gpio_get_value(template->cmd));
        if (ret)
            gpio_free(template->cmd);
    }
    if (ret) {
        dev_err(&pdev->dev, "%s: failed to setup command GPIO\n",
            template->name);
    }

    ret = gpio_request(template->slow, template->name);
    if (ret == 0) {
        ret = gpio_direction_output(template->slow,
                        gpio_get_value(template->slow));
        if (ret)
            gpio_free(template->slow);
    }
    if (ret) {
        dev_err(&pdev->dev, "%s: failed to setup slow GPIO\n",
            template->name);
        goto err_free_cmd;
    }

    rwlock_init(&led_dat->rw_lock);

    led_dat->cdev.name = template->name;
    led_dat->cdev.default_trigger = template->default_trigger;
    led_dat->cdev.blink_set = NULL;
    led_dat->cdev.brightness_set = ns2_led_set;
    led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
    led_dat->cmd = template->cmd;
    led_dat->slow = template->slow;

    ret = ns2_led_get_mode(led_dat, &mode);
    if (ret < 0)
        goto err_free_slow;

    /* Set LED initial state. */
    led_dat->sata = (mode == NS_V2_LED_SATA) ? 1 : 0;
    led_dat->cdev.brightness =
        (mode == NS_V2_LED_OFF) ? LED_OFF : LED_FULL;

    ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
    if (ret < 0)
        goto err_free_slow;

    ret = device_create_file(led_dat->cdev.dev, &dev_attr_sata);
    if (ret < 0)
        goto err_free_cdev;

    return 0;

err_free_cdev:
    led_classdev_unregister(&led_dat->cdev);
err_free_slow:
    gpio_free(led_dat->slow);
err_free_cmd:
    gpio_free(led_dat->cmd);

    return ret;
}

static void delete_ns2_led(struct ns2_led_data *led_dat)
{
    device_remove_file(led_dat->cdev.dev, &dev_attr_sata);
    led_classdev_unregister(&led_dat->cdev);
    gpio_free(led_dat->cmd);
    gpio_free(led_dat->slow);
}

static int __devinit ns2_led_probe(struct platform_device *pdev)
{
    struct ns2_led_platform_data *pdata = pdev->dev.platform_data;
    struct ns2_led_data *leds_data;
    int i;
    int ret;

    if (!pdata)
        return -EINVAL;

    leds_data = devm_kzalloc(&pdev->dev, sizeof(struct ns2_led_data) *
                pdata->num_leds, GFP_KERNEL);
    if (!leds_data)
        return -ENOMEM;

    for (i = 0; i < pdata->num_leds; i++) {
        ret = create_ns2_led(pdev, &leds_data[i], &pdata->leds[i]);
        if (ret < 0) {
            for (i = i - 1; i >= 0; i--)
                delete_ns2_led(&leds_data[i]);
            return ret;
        }
    }

    platform_set_drvdata(pdev, leds_data);

    return 0;
}

static int __devexit ns2_led_remove(struct platform_device *pdev)
{
    int i;
    struct ns2_led_platform_data *pdata = pdev->dev.platform_data;
    struct ns2_led_data *leds_data;

    leds_data = platform_get_drvdata(pdev);

    for (i = 0; i < pdata->num_leds; i++)
        delete_ns2_led(&leds_data[i]);

    platform_set_drvdata(pdev, NULL);

    return 0;
}

static struct platform_driver ns2_led_driver = {
    .probe      = ns2_led_probe,
    .remove     = __devexit_p(ns2_led_remove),
    .driver     = {
        .name   = "leds-ns2",
        .owner  = THIS_MODULE,
    },
};

module_platform_driver(ns2_led_driver);

MODULE_AUTHOR("Simon Guinot <[email protected]>");
MODULE_DESCRIPTION("Network Space v2 LED driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:leds-ns2");