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        queue_delayed_work(system_power_efficient_wq,
  91                           &data->handler, data->handling_delay);
  92        return IRQ_HANDLED;
  93}
  94
  95static int adc_jack_probe(struct platform_device *pdev)
  96{
  97        struct adc_jack_data *data;
  98        struct adc_jack_pdata *pdata = dev_get_platdata(&pdev->dev);
  99        int i, err = 0;
 100
 101        data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
 102        if (!data)
 103                return -ENOMEM;
 104
 105        if (!pdata->cable_names) {
 106                dev_err(&pdev->dev, "error: cable_names not defined.\n");
 107                return -EINVAL;
 108        }
 109
 110        data->edev = devm_extcon_dev_allocate(&pdev->dev, pdata->cable_names);
 111        if (IS_ERR(data->edev)) {
 112                dev_err(&pdev->dev, "failed to allocate extcon device\n");
 113                return -ENOMEM;
 114        }
 115        data->edev->name = pdata->name;
 116
 117        /* Check the length of array and set num_cables */
 118        for (i = 0; data->edev->supported_cable[i]; i++)
 119                ;
 120        if (i == 0 || i > SUPPORTED_CABLE_MAX) {
 121                dev_err(&pdev->dev, "error: pdata->cable_names size = %d\n",
 122                                i - 1);
 123                return -EINVAL;
 124        }
 125        data->num_cables = i;
 126
 127        if (!pdata->adc_conditions ||
 128                        !pdata->adc_conditions[0].state) {
 129                dev_err(&pdev->dev, "error: adc_conditions not defined.\n");
 130                return -EINVAL;
 131        }
 132        data->adc_conditions = pdata->adc_conditions;
 133
 134        /* Check the length of array and set num_conditions */
 135        for (i = 0; data->adc_conditions[i].state; i++)
 136                ;
 137        data->num_conditions = i;
 138
 139        data->chan = iio_channel_get(&pdev->dev, pdata->consumer_channel);
 140        if (IS_ERR(data->chan))
 141                return PTR_ERR(data->chan);
 142
 143        data->handling_delay = msecs_to_jiffies(pdata->handling_delay_ms);
 144
 145        INIT_DEFERRABLE_WORK(&data->handler, adc_jack_handler);
 146
 147        platform_set_drvdata(pdev, data);
 148
 149        err = devm_extcon_dev_register(&pdev->dev, data->edev);
 150        if (err)
 151                return err;
 152
 153        data->irq = platform_get_irq(pdev, 0);
 154        if (!data->irq) {
 155                dev_err(&pdev->dev, "platform_get_irq failed\n");
 156                return -ENODEV;
 157        }
 158
 159        err = request_any_context_irq(data->irq, adc_jack_irq_thread,
 160                        pdata->irq_flags, pdata->name, data);
 161
 162        if (err < 0) {
 163                dev_err(&pdev->dev, "error: irq %d\n", data->irq);
 164                return err;
 165        }
 166
 167        return 0;
 168}
 169
 170static int adc_jack_remove(struct platform_device *pdev)
 171{
 172        struct adc_jack_data *data = platform_get_drvdata(pdev);
 173
 174        free_irq(data->irq, data);
 175        cancel_work_sync(&data->handler.work);
 176
 177        return 0;
 178}
 179
 180static struct platform_driver adc_jack_driver = {
 181        .probe          = adc_jack_probe,
 182        .remove         = adc_jack_remove,
 183        .driver         = {
 184                .name   = "adc-jack",
 185        },
 186};
 187
 188module_platform_driver(adc_jack_driver);
 189
 190MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
 191MODULE_DESCRIPTION("ADC Jack extcon driver");
 192MODULE_LICENSE("GPL v2");
 193
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