leds-asic3.c

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/*
 *  Copyright (C) 2011 Paul Parsons <[email protected]>
 *
 *  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/init.h>
#include <linux/platform_device.h>
#include <linux/leds.h>
#include <linux/slab.h>

#include <linux/mfd/asic3.h>
#include <linux/mfd/core.h>
#include <linux/module.h>

/*
 *  The HTC ASIC3 LED GPIOs are inputs, not outputs.
 *  Hence we turn the LEDs on/off via the TimeBase register.
 */

/*
 *  When TimeBase is 4 the clock resolution is about 32Hz.
 *  This driver supports hardware blinking with an on+off
 *  period from 62ms (2 clocks) to 125s (4000 clocks).
 */
#define MS_TO_CLK(ms)   DIV_ROUND_CLOSEST(((ms)*1024), 32000)
#define CLK_TO_MS(clk)  (((clk)*32000)/1024)
#define MAX_CLK     4000            /* Fits into 12-bit Time registers */
#define MAX_MS      CLK_TO_MS(MAX_CLK)

static const unsigned int led_n_base[ASIC3_NUM_LEDS] = {
    [0] = ASIC3_LED_0_Base,
    [1] = ASIC3_LED_1_Base,
    [2] = ASIC3_LED_2_Base,
};

static void brightness_set(struct led_classdev *cdev,
    enum led_brightness value)
{
    struct platform_device *pdev = to_platform_device(cdev->dev->parent);
    const struct mfd_cell *cell = mfd_get_cell(pdev);
    struct asic3 *asic = dev_get_drvdata(pdev->dev.parent);
    u32 timebase;
    unsigned int base;

    timebase = (value == LED_OFF) ? 0 : (LED_EN|0x4);

    base = led_n_base[cell->id];
    asic3_write_register(asic, (base + ASIC3_LED_PeriodTime), 32);
    asic3_write_register(asic, (base + ASIC3_LED_DutyTime), 32);
    asic3_write_register(asic, (base + ASIC3_LED_AutoStopCount), 0);
    asic3_write_register(asic, (base + ASIC3_LED_TimeBase), timebase);
}

static int blink_set(struct led_classdev *cdev,
    unsigned long *delay_on,
    unsigned long *delay_off)
{
    struct platform_device *pdev = to_platform_device(cdev->dev->parent);
    const struct mfd_cell *cell = mfd_get_cell(pdev);
    struct asic3 *asic = dev_get_drvdata(pdev->dev.parent);
    u32 on;
    u32 off;
    unsigned int base;

    if (*delay_on > MAX_MS || *delay_off > MAX_MS)
        return -EINVAL;

    if (*delay_on == 0 && *delay_off == 0) {
        /* If both are zero then a sensible default should be chosen */
        on = MS_TO_CLK(500);
        off = MS_TO_CLK(500);
    } else {
        on = MS_TO_CLK(*delay_on);
        off = MS_TO_CLK(*delay_off);
        if ((on + off) > MAX_CLK)
            return -EINVAL;
    }

    base = led_n_base[cell->id];
    asic3_write_register(asic, (base + ASIC3_LED_PeriodTime), (on + off));
    asic3_write_register(asic, (base + ASIC3_LED_DutyTime), on);
    asic3_write_register(asic, (base + ASIC3_LED_AutoStopCount), 0);
    asic3_write_register(asic, (base + ASIC3_LED_TimeBase), (LED_EN|0x4));

    *delay_on = CLK_TO_MS(on);
    *delay_off = CLK_TO_MS(off);

    return 0;
}

static int __devinit asic3_led_probe(struct platform_device *pdev)
{
    struct asic3_led *led = pdev->dev.platform_data;
    int ret;

    ret = mfd_cell_enable(pdev);
    if (ret < 0)
        return ret;

    led->cdev = devm_kzalloc(&pdev->dev, sizeof(struct led_classdev),
                GFP_KERNEL);
    if (!led->cdev) {
        ret = -ENOMEM;
        goto out;
    }

    led->cdev->name = led->name;
    led->cdev->flags = LED_CORE_SUSPENDRESUME;
    led->cdev->brightness_set = brightness_set;
    led->cdev->blink_set = blink_set;
    led->cdev->default_trigger = led->default_trigger;

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

    return 0;

out:
    (void) mfd_cell_disable(pdev);
    return ret;
}

static int __devexit asic3_led_remove(struct platform_device *pdev)
{
    struct asic3_led *led = pdev->dev.platform_data;

    led_classdev_unregister(led->cdev);

    return mfd_cell_disable(pdev);
}

static int asic3_led_suspend(struct device *dev)
{
    struct platform_device *pdev = to_platform_device(dev);
    const struct mfd_cell *cell = mfd_get_cell(pdev);
    int ret;

    ret = 0;
    if (cell->suspend)
        ret = (*cell->suspend)(pdev);

    return ret;
}

static int asic3_led_resume(struct device *dev)
{
    struct platform_device *pdev = to_platform_device(dev);
    const struct mfd_cell *cell = mfd_get_cell(pdev);
    int ret;

    ret = 0;
    if (cell->resume)
        ret = (*cell->resume)(pdev);

    return ret;
}

static const struct dev_pm_ops asic3_led_pm_ops = {
    .suspend    = asic3_led_suspend,
    .resume     = asic3_led_resume,
};

static struct platform_driver asic3_led_driver = {
    .probe      = asic3_led_probe,
    .remove     = __devexit_p(asic3_led_remove),
    .driver     = {
        .name   = "leds-asic3",
        .owner  = THIS_MODULE,
        .pm = &asic3_led_pm_ops,
    },
};

module_platform_driver(asic3_led_driver);

MODULE_AUTHOR("Paul Parsons <[email protected]>");
MODULE_DESCRIPTION("HTC ASIC3 LED driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:leds-asic3");