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) 2016 Samsung Electronics
   7  * Chanwoo Choi <cw00.choi@samsung.com>
   8  *
   9  * Copyright (C) 2012 Samsung Electronics
  10  * MyungJoo Ham <myungjoo.ham@samsung.com>
  11  *
  12  * Modified for calling to IIO to get adc by <anish.singh@samsung.com>
  13  *
  14  * This program is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License version 2 as
  16  * published by the Free Software Foundation.
  17  *
  18  */
  19
  20 #include <linux/module.h>
  21 #include <linux/slab.h>
  22 #include <linux/device.h>
  23 #include <linux/platform_device.h>
  24 #include <linux/err.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/workqueue.h>
  27 #include <linux/iio/consumer.h>
  28 #include <linux/extcon/extcon-adc-jack.h>
  29 #include <linux/extcon.h>
  30
  31 /**
  32  * struct adc_jack_data - internal data for adc_jack device driver
  33  * @edev:               extcon device.
  34  * @cable_names:        list of supported cables.
  35  * @adc_conditions:     list of adc value conditions.
  36  * @num_conditions:     size of adc_conditions.
  37  * @irq:                irq number of attach/detach event (0 if not exist).
  38  * @handling_delay:     interrupt handler will schedule extcon event
  39  *                      handling at handling_delay jiffies.
  40  * @handler:            extcon event handler called by interrupt handler.
  41  * @chan:               iio channel being queried.
  42  */
  43 struct adc_jack_data {
  44         struct extcon_dev *edev;
  45
  46         const unsigned int **cable_names;
  47         struct adc_jack_cond *adc_conditions;
  48         int num_conditions;
  49
  50         int irq;
  51         unsigned long handling_delay; /* in jiffies */
  52         struct delayed_work handler;
  53
  54         struct iio_channel *chan;
  55 };
  56
  57 static void adc_jack_handler(struct work_struct *work)
  58 {
  59         struct adc_jack_data *data = container_of(to_delayed_work(work),
  60                         struct adc_jack_data,
  61                         handler);
  62         struct adc_jack_cond *def;
  63         int ret, adc_val;
  64         int i;
  65
  66         ret = iio_read_channel_raw(data->chan, &adc_val);
  67         if (ret < 0) {
  68                 dev_err(&data->edev->dev, "read channel() error: %d\n", ret);
  69                 return;
  70         }
  71
  72         /* Get state from adc value with adc_conditions */
  73         for (i = 0; i < data->num_conditions; i++) {
  74                 def = &data->adc_conditions[i];
  75                 if (def->min_adc <= adc_val && def->max_adc >= adc_val) {
  76                         extcon_set_cable_state_(data->edev, def->id, true);
  77                         return;
  78                 }
  79         }
  80
  81         /* Set the detached state if adc value is not included in the range */
  82         for (i = 0; i < data->num_conditions; i++) {
  83                 def = &data->adc_conditions[i];
  84                 extcon_set_cable_state_(data->edev, def->id, false);
  85         }
  86 }
  87
  88 static irqreturn_t adc_jack_irq_thread(int irq, void *_data)
  89 {
  90         struct adc_jack_data *data = _data;
  91
  92         queue_delayed_work(system_power_efficient_wq,
  93                            &data->handler, data->handling_delay);
  94         return IRQ_HANDLED;
  95 }
  96
  97 static int adc_jack_probe(struct platform_device *pdev)
  98 {
  99         struct adc_jack_data *data;
 100         struct adc_jack_pdata *pdata = dev_get_platdata(&pdev->dev);
 101         int i, err = 0;
 102
 103         data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
 104         if (!data)
 105                 return -ENOMEM;
 106
 107         if (!pdata->cable_names) {
 108                 dev_err(&pdev->dev, "error: cable_names not defined.\n");
 109                 return -EINVAL;
 110         }
 111
 112         data->edev = devm_extcon_dev_allocate(&pdev->dev, pdata->cable_names);
 113         if (IS_ERR(data->edev)) {
 114                 dev_err(&pdev->dev, "failed to allocate extcon device\n");
 115                 return -ENOMEM;
 116         }
 117
 118         if (!pdata->adc_conditions) {
 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].id != EXTCON_NONE; i++);
 126         data->num_conditions = i;
 127
 128         data->chan = iio_channel_get(&pdev->dev, pdata->consumer_channel);
 129         if (IS_ERR(data->chan))
 130                 return PTR_ERR(data->chan);
 131
 132         data->handling_delay = msecs_to_jiffies(pdata->handling_delay_ms);
 133
 134         INIT_DEFERRABLE_WORK(&data->handler, adc_jack_handler);
 135
 136         platform_set_drvdata(pdev, data);
 137
 138         err = devm_extcon_dev_register(&pdev->dev, data->edev);
 139         if (err)
 140                 return err;
 141
 142         data->irq = platform_get_irq(pdev, 0);
 143         if (!data->irq) {
 144                 dev_err(&pdev->dev, "platform_get_irq failed\n");
 145                 return -ENODEV;
 146         }
 147
 148         err = request_any_context_irq(data->irq, adc_jack_irq_thread,
 149                         pdata->irq_flags, pdata->name, data);
 150
 151         if (err < 0) {
 152                 dev_err(&pdev->dev, "error: irq %d\n", data->irq);
 153                 return err;
 154         }
 155
 156         return 0;
 157 }
 158
 159 static int adc_jack_remove(struct platform_device *pdev)
 160 {
 161         struct adc_jack_data *data = platform_get_drvdata(pdev);
 162
 163         free_irq(data->irq, data);
 164         cancel_work_sync(&data->handler.work);
 165         iio_channel_release(data->chan);
 166
 167         return 0;
 168 }
 169
 170 static struct platform_driver adc_jack_driver = {
 171         .probe          = adc_jack_probe,
 172         .remove         = adc_jack_remove,
 173         .driver         = {
 174                 .name   = "adc-jack",
 175         },
 176 };
 177
 178 module_platform_driver(adc_jack_driver);
 179
 180 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
 181 MODULE_DESCRIPTION("ADC Jack extcon driver");
 182 MODULE_LICENSE("GPL v2");