leds-netxbig.c

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/*
 * leds-netxbig.c - Driver for the 2Big and 5Big Network series LEDs
 *
 * Copyright (C) 2010 LaCie
 *
 * Author: Simon Guinot <[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/module.h>
#include <linux/init.h>
#include <linux/irq.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/platform_device.h>
#include <linux/gpio.h>
#include <linux/leds.h>
#include <linux/platform_data/leds-kirkwood-netxbig.h>

/*
 * GPIO extension bus.
 */

static DEFINE_SPINLOCK(gpio_ext_lock);

static void gpio_ext_set_addr(struct netxbig_gpio_ext *gpio_ext, int addr)
{
    int pin;

    for (pin = 0; pin < gpio_ext->num_addr; pin++)
        gpio_set_value(gpio_ext->addr[pin], (addr >> pin) & 1);
}

static void gpio_ext_set_data(struct netxbig_gpio_ext *gpio_ext, int data)
{
    int pin;

    for (pin = 0; pin < gpio_ext->num_data; pin++)
        gpio_set_value(gpio_ext->data[pin], (data >> pin) & 1);
}

static void gpio_ext_enable_select(struct netxbig_gpio_ext *gpio_ext)
{
    /* Enable select is done on the raising edge. */
    gpio_set_value(gpio_ext->enable, 0);
    gpio_set_value(gpio_ext->enable, 1);
}

static void gpio_ext_set_value(struct netxbig_gpio_ext *gpio_ext,
                   int addr, int value)
{
    unsigned long flags;

    spin_lock_irqsave(&gpio_ext_lock, flags);
    gpio_ext_set_addr(gpio_ext, addr);
    gpio_ext_set_data(gpio_ext, value);
    gpio_ext_enable_select(gpio_ext);
    spin_unlock_irqrestore(&gpio_ext_lock, flags);
}

static int __devinit gpio_ext_init(struct netxbig_gpio_ext *gpio_ext)
{
    int err;
    int i;

    if (unlikely(!gpio_ext))
        return -EINVAL;

    /* Configure address GPIOs. */
    for (i = 0; i < gpio_ext->num_addr; i++) {
        err = gpio_request_one(gpio_ext->addr[i], GPIOF_OUT_INIT_LOW,
                       "GPIO extension addr");
        if (err)
            goto err_free_addr;
    }
    /* Configure data GPIOs. */
    for (i = 0; i < gpio_ext->num_data; i++) {
        err = gpio_request_one(gpio_ext->data[i], GPIOF_OUT_INIT_LOW,
                   "GPIO extension data");
        if (err)
            goto err_free_data;
    }
    /* Configure "enable select" GPIO. */
    err = gpio_request_one(gpio_ext->enable, GPIOF_OUT_INIT_LOW,
                   "GPIO extension enable");
    if (err)
        goto err_free_data;

    return 0;

err_free_data:
    for (i = i - 1; i >= 0; i--)
        gpio_free(gpio_ext->data[i]);
    i = gpio_ext->num_addr;
err_free_addr:
    for (i = i - 1; i >= 0; i--)
        gpio_free(gpio_ext->addr[i]);

    return err;
}

static void gpio_ext_free(struct netxbig_gpio_ext *gpio_ext)
{
    int i;

    gpio_free(gpio_ext->enable);
    for (i = gpio_ext->num_addr - 1; i >= 0; i--)
        gpio_free(gpio_ext->addr[i]);
    for (i = gpio_ext->num_data - 1; i >= 0; i--)
        gpio_free(gpio_ext->data[i]);
}

/*
 * Class LED driver.
 */

struct netxbig_led_data {
    struct netxbig_gpio_ext *gpio_ext;
    struct led_classdev cdev;
    int         mode_addr;
    int         *mode_val;
    int         bright_addr;
    int         bright_max;
    struct          netxbig_led_timer *timer;
    int         num_timer;
    enum netxbig_led_mode   mode;
    int         sata;
    spinlock_t      lock;
};

static int netxbig_led_get_timer_mode(enum netxbig_led_mode *mode,
                      unsigned long delay_on,
                      unsigned long delay_off,
                      struct netxbig_led_timer *timer,
                      int num_timer)
{
    int i;

    for (i = 0; i < num_timer; i++) {
        if (timer[i].delay_on == delay_on &&
            timer[i].delay_off == delay_off) {
            *mode = timer[i].mode;
            return 0;
        }
    }
    return -EINVAL;
}

static int netxbig_led_blink_set(struct led_classdev *led_cdev,
                 unsigned long *delay_on,
                 unsigned long *delay_off)
{
    struct netxbig_led_data *led_dat =
        container_of(led_cdev, struct netxbig_led_data, cdev);
    enum netxbig_led_mode mode;
    int mode_val;
    int ret;

    /* Look for a LED mode with the requested timer frequency. */
    ret = netxbig_led_get_timer_mode(&mode, *delay_on, *delay_off,
                     led_dat->timer, led_dat->num_timer);
    if (ret < 0)
        return ret;

    mode_val = led_dat->mode_val[mode];
    if (mode_val == NETXBIG_LED_INVALID_MODE)
        return -EINVAL;

    spin_lock_irq(&led_dat->lock);

    gpio_ext_set_value(led_dat->gpio_ext, led_dat->mode_addr, mode_val);
    led_dat->mode = mode;

    spin_unlock_irq(&led_dat->lock);

    return 0;
}

static void netxbig_led_set(struct led_classdev *led_cdev,
                enum led_brightness value)
{
    struct netxbig_led_data *led_dat =
        container_of(led_cdev, struct netxbig_led_data, cdev);
    enum netxbig_led_mode mode;
    int mode_val, bright_val;
    int set_brightness = 1;
    unsigned long flags;

    spin_lock_irqsave(&led_dat->lock, flags);

    if (value == LED_OFF) {
        mode = NETXBIG_LED_OFF;
        set_brightness = 0;
    } else {
        if (led_dat->sata)
            mode = NETXBIG_LED_SATA;
        else if (led_dat->mode == NETXBIG_LED_OFF)
            mode = NETXBIG_LED_ON;
        else /* Keep 'timer' mode. */
            mode = led_dat->mode;
    }
    mode_val = led_dat->mode_val[mode];

    gpio_ext_set_value(led_dat->gpio_ext, led_dat->mode_addr, mode_val);
    led_dat->mode = mode;
    /*
     * Note that the brightness register is shared between all the
     * SATA LEDs. So, change the brightness setting for a single
     * SATA LED will affect all the others.
     */
    if (set_brightness) {
        bright_val = DIV_ROUND_UP(value * led_dat->bright_max,
                      LED_FULL);
        gpio_ext_set_value(led_dat->gpio_ext,
                   led_dat->bright_addr, bright_val);
    }

    spin_unlock_irqrestore(&led_dat->lock, flags);
}

static ssize_t netxbig_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 netxbig_led_data *led_dat =
        container_of(led_cdev, struct netxbig_led_data, cdev);
    unsigned long enable;
    enum netxbig_led_mode mode;
    int mode_val;
    int ret;

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

    enable = !!enable;

    spin_lock_irq(&led_dat->lock);

    if (led_dat->sata == enable) {
        ret = count;
        goto exit_unlock;
    }

    if (led_dat->mode != NETXBIG_LED_ON &&
        led_dat->mode != NETXBIG_LED_SATA)
        mode = led_dat->mode; /* Keep modes 'off' and 'timer'. */
    else if (enable)
        mode = NETXBIG_LED_SATA;
    else
        mode = NETXBIG_LED_ON;

    mode_val = led_dat->mode_val[mode];
    if (mode_val == NETXBIG_LED_INVALID_MODE) {
        ret = -EINVAL;
        goto exit_unlock;
    }

    gpio_ext_set_value(led_dat->gpio_ext, led_dat->mode_addr, mode_val);
    led_dat->mode = mode;
    led_dat->sata = enable;

    ret = count;

exit_unlock:
    spin_unlock_irq(&led_dat->lock);

    return ret;
}

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

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

static DEVICE_ATTR(sata, 0644, netxbig_led_sata_show, netxbig_led_sata_store);

static void delete_netxbig_led(struct netxbig_led_data *led_dat)
{
    if (led_dat->mode_val[NETXBIG_LED_SATA] != NETXBIG_LED_INVALID_MODE)
        device_remove_file(led_dat->cdev.dev, &dev_attr_sata);
    led_classdev_unregister(&led_dat->cdev);
}

static int __devinit
create_netxbig_led(struct platform_device *pdev,
           struct netxbig_led_data *led_dat,
           const struct netxbig_led *template)
{
    struct netxbig_led_platform_data *pdata = pdev->dev.platform_data;
    int ret;

    spin_lock_init(&led_dat->lock);
    led_dat->gpio_ext = pdata->gpio_ext;
    led_dat->cdev.name = template->name;
    led_dat->cdev.default_trigger = template->default_trigger;
    led_dat->cdev.blink_set = netxbig_led_blink_set;
    led_dat->cdev.brightness_set = netxbig_led_set;
    /*
     * Because the GPIO extension bus don't allow to read registers
     * value, there is no way to probe the LED initial state.
     * So, the initial sysfs LED value for the "brightness" and "sata"
     * attributes are inconsistent.
     *
     * Note that the initial LED state can't be reconfigured.
     * The reason is that the LED behaviour must stay uniform during
     * the whole boot process (bootloader+linux).
     */
    led_dat->sata = 0;
    led_dat->cdev.brightness = LED_OFF;
    led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
    led_dat->mode_addr = template->mode_addr;
    led_dat->mode_val = template->mode_val;
    led_dat->bright_addr = template->bright_addr;
    led_dat->bright_max = (1 << pdata->gpio_ext->num_data) - 1;
    led_dat->timer = pdata->timer;
    led_dat->num_timer = pdata->num_timer;

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

    /*
     * If available, expose the SATA activity blink capability through
     * a "sata" sysfs attribute.
     */
    if (led_dat->mode_val[NETXBIG_LED_SATA] != NETXBIG_LED_INVALID_MODE) {
        ret = device_create_file(led_dat->cdev.dev, &dev_attr_sata);
        if (ret)
            led_classdev_unregister(&led_dat->cdev);
    }

    return ret;
}

static int __devinit netxbig_led_probe(struct platform_device *pdev)
{
    struct netxbig_led_platform_data *pdata = pdev->dev.platform_data;
    struct netxbig_led_data *leds_data;
    int i;
    int ret;

    if (!pdata)
        return -EINVAL;

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

    ret = gpio_ext_init(pdata->gpio_ext);
    if (ret < 0)
        return ret;

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

    platform_set_drvdata(pdev, leds_data);

    return 0;

err_free_leds:
    for (i = i - 1; i >= 0; i--)
        delete_netxbig_led(&leds_data[i]);

    gpio_ext_free(pdata->gpio_ext);
    return ret;
}

static int __devexit netxbig_led_remove(struct platform_device *pdev)
{
    struct netxbig_led_platform_data *pdata = pdev->dev.platform_data;
    struct netxbig_led_data *leds_data;
    int i;

    leds_data = platform_get_drvdata(pdev);

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

    gpio_ext_free(pdata->gpio_ext);

    return 0;
}

static struct platform_driver netxbig_led_driver = {
    .probe      = netxbig_led_probe,
    .remove     = __devexit_p(netxbig_led_remove),
    .driver     = {
        .name   = "leds-netxbig",
        .owner  = THIS_MODULE,
    },
};

module_platform_driver(netxbig_led_driver);

MODULE_AUTHOR("Simon Guinot <[email protected]>");
MODULE_DESCRIPTION("LED driver for LaCie xBig Network boards");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:leds-netxbig");