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Linux/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");
181 

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