linux/drivers/extcon/extcon-adc-jack.c
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   1/*
   2 * drivers/extcon/extcon-adc-jack.c
   3 *
   4 * Analog Jack extcon driver with ADC-based detection capability.
   5 *
   6 * Copyright (C) 2012 Samsung Electronics
   7 * MyungJoo Ham <myungjoo.ham@samsung.com>
   8 *
   9 * Modified for calling to IIO to get adc by <anish.singh@samsung.com>
  10 *
  11 * This program is free software; you can redistribute it and/or modify
  12 * it under the terms of the GNU General Public License version 2 as
  13 * published by the Free Software Foundation.
  14 *
  15 */
  16
  17#include <linux/module.h>
  18#include <linux/slab.h>
  19#include <linux/device.h>
  20#include <linux/platform_device.h>
  21#include <linux/err.h>
  22#include <linux/interrupt.h>
  23#include <linux/workqueue.h>
  24#include <linux/iio/consumer.h>
  25#include <linux/extcon/extcon-adc-jack.h>
  26#include <linux/extcon.h>
  27
  28/**
  29 * struct adc_jack_data - internal data for adc_jack device driver
  30 * @edev        - extcon device.
  31 * @cable_names - list of supported cables.
  32 * @num_cables  - size of cable_names.
  33 * @adc_conditions       - list of adc value conditions.
  34 * @num_conditions       - size of adc_conditions.
  35 * @irq         - irq number of attach/detach event (0 if not exist).
  36 * @handling_delay      - interrupt handler will schedule extcon event
  37 *                      handling at handling_delay jiffies.
  38 * @handler     - extcon event handler called by interrupt handler.
  39 * @chan       - iio channel being queried.
  40 */
  41struct adc_jack_data {
  42        struct extcon_dev edev;
  43
  44        const char **cable_names;
  45        int num_cables;
  46        struct adc_jack_cond *adc_conditions;
  47        int num_conditions;
  48
  49        int irq;
  50        unsigned long handling_delay; /* in jiffies */
  51        struct delayed_work handler;
  52
  53        struct iio_channel *chan;
  54};
  55
  56static void adc_jack_handler(struct work_struct *work)
  57{
  58        struct adc_jack_data *data = container_of(to_delayed_work(work),
  59                        struct adc_jack_data,
  60                        handler);
  61        u32 state = 0;
  62        int ret, adc_val;
  63        int i;
  64
  65        ret = iio_read_channel_raw(data->chan, &adc_val);
  66        if (ret < 0) {
  67                dev_err(data->edev.dev, "read channel() error: %d\n", ret);
  68                return;
  69        }
  70
  71        /* Get state from adc value with adc_conditions */
  72        for (i = 0; i < data->num_conditions; i++) {
  73                struct adc_jack_cond *def = &data->adc_conditions[i];
  74                if (!def->state)
  75                        break;
  76                if (def->min_adc <= adc_val && def->max_adc >= adc_val) {
  77                        state = def->state;
  78                        break;
  79                }
  80        }
  81        /* if no def has met, it means state = 0 (no cables attached) */
  82
  83        extcon_set_state(&data->edev, state);
  84}
  85
  86static irqreturn_t adc_jack_irq_thread(int irq, void *_data)
  87{
  88        struct adc_jack_data *data = _data;
  89
  90        schedule_delayed_work(&data->handler, data->handling_delay);
  91        return IRQ_HANDLED;
  92}
  93
  94static int __devinit adc_jack_probe(struct platform_device *pdev)
  95{
  96        struct adc_jack_data *data;
  97        struct adc_jack_pdata *pdata = pdev->dev.platform_data;
  98        int i, err = 0;
  99
 100        data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
 101        if (!data)
 102                return -ENOMEM;
 103
 104        data->edev.name = pdata->name;
 105
 106        if (!pdata->cable_names) {
 107                err = -EINVAL;
 108                dev_err(&pdev->dev, "error: cable_names not defined.\n");
 109                goto out;
 110        }
 111
 112        data->edev.supported_cable = pdata->cable_names;
 113
 114        /* Check the length of array and set num_cables */
 115        for (i = 0; data->edev.supported_cable[i]; i++)
 116                ;
 117        if (i == 0 || i > SUPPORTED_CABLE_MAX) {
 118                err = -EINVAL;
 119                dev_err(&pdev->dev, "error: pdata->cable_names size = %d\n",
 120                                i - 1);
 121                goto out;
 122        }
 123        data->num_cables = i;
 124
 125        if (!pdata->adc_conditions ||
 126                        !pdata->adc_conditions[0].state) {
 127                err = -EINVAL;
 128                dev_err(&pdev->dev, "error: adc_conditions not defined.\n");
 129                goto out;
 130        }
 131        data->adc_conditions = pdata->adc_conditions;
 132
 133        /* Check the length of array and set num_conditions */
 134        for (i = 0; data->adc_conditions[i].state; i++)
 135                ;
 136        data->num_conditions = i;
 137
 138        data->chan = iio_channel_get(dev_name(&pdev->dev),
 139                        pdata->consumer_channel);
 140        if (IS_ERR(data->chan)) {
 141                err = PTR_ERR(data->chan);
 142                goto out;
 143        }
 144
 145        data->handling_delay = msecs_to_jiffies(pdata->handling_delay_ms);
 146
 147        INIT_DEFERRABLE_WORK(&data->handler, adc_jack_handler);
 148
 149        platform_set_drvdata(pdev, data);
 150
 151        err = extcon_dev_register(&data->edev, &pdev->dev);
 152        if (err)
 153                goto out;
 154
 155        data->irq = platform_get_irq(pdev, 0);
 156        if (!data->irq) {
 157                dev_err(&pdev->dev, "platform_get_irq failed\n");
 158                err = -ENODEV;
 159                goto err_irq;
 160        }
 161
 162        err = request_any_context_irq(data->irq, adc_jack_irq_thread,
 163                        pdata->irq_flags, pdata->name, data);
 164
 165        if (err < 0) {
 166                dev_err(&pdev->dev, "error: irq %d\n", data->irq);
 167                goto err_irq;
 168        }
 169
 170        return 0;
 171
 172err_irq:
 173        extcon_dev_unregister(&data->edev);
 174out:
 175        return err;
 176}
 177
 178static int __devexit adc_jack_remove(struct platform_device *pdev)
 179{
 180        struct adc_jack_data *data = platform_get_drvdata(pdev);
 181
 182        free_irq(data->irq, data);
 183        cancel_work_sync(&data->handler.work);
 184        extcon_dev_unregister(&data->edev);
 185
 186        return 0;
 187}
 188
 189static struct platform_driver adc_jack_driver = {
 190        .probe          = adc_jack_probe,
 191        .remove         = __devexit_p(adc_jack_remove),
 192        .driver         = {
 193                .name   = "adc-jack",
 194                .owner  = THIS_MODULE,
 195        },
 196};
 197
 198module_platform_driver(adc_jack_driver);
 199
 200MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
 201MODULE_DESCRIPTION("ADC Jack extcon driver");
 202MODULE_LICENSE("GPL v2");
 203
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