drivers/extcon/extcon-adc-jack.c

   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  * @adc_conditions:     list of adc value conditions.
  33  * @num_conditions:     size of adc_conditions.
  34  * @irq:                irq number of attach/detach event (0 if not exist).
  35  * @handling_delay:     interrupt handler will schedule extcon event
  36  *                      handling at handling_delay jiffies.
  37  * @handler:            extcon event handler called by interrupt handler.
  38  * @chan:               iio channel being queried.
  39  */
  40 struct adc_jack_data {
  41         struct extcon_dev *edev;
  42
  43         const unsigned int **cable_names;
  44         struct adc_jack_cond *adc_conditions;
  45         int num_conditions;
  46
  47         int irq;
  48         unsigned long handling_delay; /* in jiffies */
  49         struct delayed_work handler;
  50
  51         struct iio_channel *chan;
  52 };
  53
  54 static void adc_jack_handler(struct work_struct *work)
  55 {
  56         struct adc_jack_data *data = container_of(to_delayed_work(work),
  57                         struct adc_jack_data,
  58                         handler);
  59         u32 state = 0;
  60         int ret, adc_val;
  61         int i;
  62
  63         ret = iio_read_channel_raw(data->chan, &adc_val);
  64         if (ret < 0) {
  65                 dev_err(&data->edev->dev, "read channel() error: %d\n", ret);
  66                 return;
  67         }
  68
  69         /* Get state from adc value with adc_conditions */
  70         for (i = 0; i < data->num_conditions; i++) {
  71                 struct adc_jack_cond *def = &data->adc_conditions[i];
  72                 if (!def->state)
  73                         break;
  74                 if (def->min_adc <= adc_val && def->max_adc >= adc_val) {
  75                         state = def->state;
  76                         break;
  77                 }
  78         }
  79         /* if no def has met, it means state = 0 (no cables attached) */
  80
  81         extcon_set_state(data->edev, state);
  82 }
  83
  84 static irqreturn_t adc_jack_irq_thread(int irq, void *_data)
  85 {
  86         struct adc_jack_data *data = _data;
  87
  88         queue_delayed_work(system_power_efficient_wq,
  89                            &data->handler, data->handling_delay);
  90         return IRQ_HANDLED;
  91 }
  92
  93 static int adc_jack_probe(struct platform_device *pdev)
  94 {
  95         struct adc_jack_data *data;
  96         struct adc_jack_pdata *pdata = dev_get_platdata(&pdev->dev);
  97         int i, err = 0;
  98
  99         data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
 100         if (!data)
 101                 return -ENOMEM;
 102
 103         if (!pdata->cable_names) {
 104                 dev_err(&pdev->dev, "error: cable_names not defined.\n");
 105                 return -EINVAL;
 106         }
 107
 108         data->edev = devm_extcon_dev_allocate(&pdev->dev, pdata->cable_names);
 109         if (IS_ERR(data->edev)) {
 110                 dev_err(&pdev->dev, "failed to allocate extcon device\n");
 111                 return -ENOMEM;
 112         }
 113
 114         if (!pdata->adc_conditions ||
 115                         !pdata->adc_conditions[0].state) {
 116                 dev_err(&pdev->dev, "error: adc_conditions not defined.\n");
 117                 return -EINVAL;
 118         }
 119         data->adc_conditions = pdata->adc_conditions;
 120
 121         /* Check the length of array and set num_conditions */
 122         for (i = 0; data->adc_conditions[i].state; i++)
 123                 ;
 124         data->num_conditions = i;
 125
 126         data->chan = iio_channel_get(&pdev->dev, pdata->consumer_channel);
 127         if (IS_ERR(data->chan))
 128                 return PTR_ERR(data->chan);
 129
 130         data->handling_delay = msecs_to_jiffies(pdata->handling_delay_ms);
 131
 132         INIT_DEFERRABLE_WORK(&data->handler, adc_jack_handler);
 133
 134         platform_set_drvdata(pdev, data);
 135
 136         err = devm_extcon_dev_register(&pdev->dev, data->edev);
 137         if (err)
 138                 return err;
 139
 140         data->irq = platform_get_irq(pdev, 0);
 141         if (!data->irq) {
 142                 dev_err(&pdev->dev, "platform_get_irq failed\n");
 143                 return -ENODEV;
 144         }
 145
 146         err = request_any_context_irq(data->irq, adc_jack_irq_thread,
 147                         pdata->irq_flags, pdata->name, data);
 148
 149         if (err < 0) {
 150                 dev_err(&pdev->dev, "error: irq %d\n", data->irq);
 151                 return err;
 152         }
 153
 154         return 0;
 155 }
 156
 157 static int adc_jack_remove(struct platform_device *pdev)
 158 {
 159         struct adc_jack_data *data = platform_get_drvdata(pdev);
 160
 161         free_irq(data->irq, data);
 162         cancel_work_sync(&data->handler.work);
 163         iio_channel_release(data->chan);
 164
 165         return 0;
 166 }
 167
 168 static struct platform_driver adc_jack_driver = {
 169         .probe          = adc_jack_probe,
 170         .remove         = adc_jack_remove,
 171         .driver         = {
 172                 .name   = "adc-jack",
 173         },
 174 };
 175
 176 module_platform_driver(adc_jack_driver);
 177
 178 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
 179 MODULE_DESCRIPTION("ADC Jack extcon driver");
 180 MODULE_LICENSE("GPL v2");