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 device *dev;
  42         struct extcon_dev *edev;
  43
  44         const unsigned int **cable_names;
  45         struct adc_jack_cond *adc_conditions;
  46         int num_conditions;
  47
  48         int irq;
  49         unsigned long handling_delay; /* in jiffies */
  50         struct delayed_work handler;
  51
  52         struct iio_channel *chan;
  53         bool wakeup_source;
  54 };
  55
  56 static 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
  86 static 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
  95 static 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->dev = &pdev->dev;
 111         data->edev = devm_extcon_dev_allocate(&pdev->dev, pdata->cable_names);
 112         if (IS_ERR(data->edev)) {
 113                 dev_err(&pdev->dev, "failed to allocate extcon device\n");
 114                 return -ENOMEM;
 115         }
 116
 117         if (!pdata->adc_conditions ||
 118                         !pdata->adc_conditions[0].state) {
 119                 dev_err(&pdev->dev, "error: adc_conditions not defined.\n");
 120                 return -EINVAL;
 121         }
 122         data->adc_conditions = pdata->adc_conditions;
 123
 124         /* Check the length of array and set num_conditions */
 125         for (i = 0; data->adc_conditions[i].state; i++)
 126                 ;
 127         data->num_conditions = i;
 128
 129         data->chan = iio_channel_get(&pdev->dev, pdata->consumer_channel);
 130         if (IS_ERR(data->chan))
 131                 return PTR_ERR(data->chan);
 132
 133         data->handling_delay = msecs_to_jiffies(pdata->handling_delay_ms);
 134         data->wakeup_source = pdata->wakeup_source;
 135
 136         INIT_DEFERRABLE_WORK(&data->handler, adc_jack_handler);
 137
 138         platform_set_drvdata(pdev, data);
 139
 140         err = devm_extcon_dev_register(&pdev->dev, data->edev);
 141         if (err)
 142                 return err;
 143
 144         data->irq = platform_get_irq(pdev, 0);
 145         if (!data->irq) {
 146                 dev_err(&pdev->dev, "platform_get_irq failed\n");
 147                 return -ENODEV;
 148         }
 149
 150         err = request_any_context_irq(data->irq, adc_jack_irq_thread,
 151                         pdata->irq_flags, pdata->name, data);
 152
 153         if (err < 0) {
 154                 dev_err(&pdev->dev, "error: irq %d\n", data->irq);
 155                 return err;
 156         }
 157
 158         if (data->wakeup_source)
 159                 device_init_wakeup(&pdev->dev, 1);
 160
 161         return 0;
 162 }
 163
 164 static int adc_jack_remove(struct platform_device *pdev)
 165 {
 166         struct adc_jack_data *data = platform_get_drvdata(pdev);
 167
 168         free_irq(data->irq, data);
 169         cancel_work_sync(&data->handler.work);
 170         iio_channel_release(data->chan);
 171
 172         return 0;
 173 }
 174
 175 #ifdef CONFIG_PM_SLEEP
 176 static int adc_jack_suspend(struct device *dev)
 177 {
 178         struct adc_jack_data *data = dev_get_drvdata(dev);
 179
 180         cancel_delayed_work_sync(&data->handler);
 181         if (device_may_wakeup(data->dev))
 182                 enable_irq_wake(data->irq);
 183
 184         return 0;
 185 }
 186
 187 static int adc_jack_resume(struct device *dev)
 188 {
 189         struct adc_jack_data *data = dev_get_drvdata(dev);
 190
 191         if (device_may_wakeup(data->dev))
 192                 disable_irq_wake(data->irq);
 193
 194         return 0;
 195 }
 196 #endif /* CONFIG_PM_SLEEP */
 197
 198 static SIMPLE_DEV_PM_OPS(adc_jack_pm_ops,
 199                 adc_jack_suspend, adc_jack_resume);
 200
 201 static struct platform_driver adc_jack_driver = {
 202         .probe          = adc_jack_probe,
 203         .remove         = adc_jack_remove,
 204         .driver         = {
 205                 .name   = "adc-jack",
 206                 .pm = &adc_jack_pm_ops,
 207         },
 208 };
 209
 210 module_platform_driver(adc_jack_driver);
 211
 212 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
 213 MODULE_DESCRIPTION("ADC Jack extcon driver");
 214 MODULE_LICENSE("GPL v2");