extcon-adc-jack.c

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/*
 * drivers/extcon/extcon-adc-jack.c
 *
 * Analog Jack extcon driver with ADC-based detection capability.
 *
 * Copyright (C) 2012 Samsung Electronics
 * MyungJoo Ham <[email protected]>
 *
 * Modified for calling to IIO to get adc by <[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/module.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/workqueue.h>
#include <linux/iio/consumer.h>
#include <linux/extcon/extcon-adc-jack.h>
#include <linux/extcon.h>

struct adc_jack_data {
    struct extcon_dev edev;

    const char **cable_names;
    int num_cables;
    struct adc_jack_cond *adc_conditions;
    int num_conditions;

    int irq;
    unsigned long handling_delay; /* in jiffies */
    struct delayed_work handler;

    struct iio_channel *chan;
};

static void adc_jack_handler(struct work_struct *work)
{
    struct adc_jack_data *data = container_of(to_delayed_work(work),
            struct adc_jack_data,
            handler);
    u32 state = 0;
    int ret, adc_val;
    int i;

    ret = iio_read_channel_raw(data->chan, &adc_val);
    if (ret < 0) {
        dev_err(data->edev.dev, "read channel() error: %d\n", ret);
        return;
    }

    /* Get state from adc value with adc_conditions */
    for (i = 0; i < data->num_conditions; i++) {
        struct adc_jack_cond *def = &data->adc_conditions[i];
        if (!def->state)
            break;
        if (def->min_adc <= adc_val && def->max_adc >= adc_val) {
            state = def->state;
            break;
        }
    }
    /* if no def has met, it means state = 0 (no cables attached) */

    extcon_set_state(&data->edev, state);
}

static irqreturn_t adc_jack_irq_thread(int irq, void *_data)
{
    struct adc_jack_data *data = _data;

    schedule_delayed_work(&data->handler, data->handling_delay);
    return IRQ_HANDLED;
}

static int __devinit adc_jack_probe(struct platform_device *pdev)
{
    struct adc_jack_data *data;
    struct adc_jack_pdata *pdata = pdev->dev.platform_data;
    int i, err = 0;

    data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
    if (!data)
        return -ENOMEM;

    data->edev.name = pdata->name;

    if (!pdata->cable_names) {
        err = -EINVAL;
        dev_err(&pdev->dev, "error: cable_names not defined.\n");
        goto out;
    }

    data->edev.supported_cable = pdata->cable_names;

    /* Check the length of array and set num_cables */
    for (i = 0; data->edev.supported_cable[i]; i++)
        ;
    if (i == 0 || i > SUPPORTED_CABLE_MAX) {
        err = -EINVAL;
        dev_err(&pdev->dev, "error: pdata->cable_names size = %d\n",
                i - 1);
        goto out;
    }
    data->num_cables = i;

    if (!pdata->adc_conditions ||
            !pdata->adc_conditions[0].state) {
        err = -EINVAL;
        dev_err(&pdev->dev, "error: adc_conditions not defined.\n");
        goto out;
    }
    data->adc_conditions = pdata->adc_conditions;

    /* Check the length of array and set num_conditions */
    for (i = 0; data->adc_conditions[i].state; i++)
        ;
    data->num_conditions = i;

    data->chan = iio_channel_get(dev_name(&pdev->dev),
            pdata->consumer_channel);
    if (IS_ERR(data->chan)) {
        err = PTR_ERR(data->chan);
        goto out;
    }

    data->handling_delay = msecs_to_jiffies(pdata->handling_delay_ms);

    INIT_DEFERRABLE_WORK(&data->handler, adc_jack_handler);

    platform_set_drvdata(pdev, data);

    err = extcon_dev_register(&data->edev, &pdev->dev);
    if (err)
        goto out;

    data->irq = platform_get_irq(pdev, 0);
    if (!data->irq) {
        dev_err(&pdev->dev, "platform_get_irq failed\n");
        err = -ENODEV;
        goto err_irq;
    }

    err = request_any_context_irq(data->irq, adc_jack_irq_thread,
            pdata->irq_flags, pdata->name, data);

    if (err < 0) {
        dev_err(&pdev->dev, "error: irq %d\n", data->irq);
        goto err_irq;
    }

    return 0;

err_irq:
    extcon_dev_unregister(&data->edev);
out:
    return err;
}

static int __devexit adc_jack_remove(struct platform_device *pdev)
{
    struct adc_jack_data *data = platform_get_drvdata(pdev);

    free_irq(data->irq, data);
    cancel_work_sync(&data->handler.work);
    extcon_dev_unregister(&data->edev);

    return 0;
}

static struct platform_driver adc_jack_driver = {
    .probe          = adc_jack_probe,
    .remove         = __devexit_p(adc_jack_remove),
    .driver         = {
        .name   = "adc-jack",
        .owner  = THIS_MODULE,
    },
};

module_platform_driver(adc_jack_driver);

MODULE_AUTHOR("MyungJoo Ham <[email protected]>");
MODULE_DESCRIPTION("ADC Jack extcon driver");
MODULE_LICENSE("GPL v2");