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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  * @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  */
 41 struct 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 
 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->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 
170 static 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 
180 static struct platform_driver adc_jack_driver = {
181         .probe          = adc_jack_probe,
182         .remove         = adc_jack_remove,
183         .driver         = {
184                 .name   = "adc-jack",
185                 .owner  = THIS_MODULE,
186         },
187 };
188 
189 module_platform_driver(adc_jack_driver);
190 
191 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
192 MODULE_DESCRIPTION("ADC Jack extcon driver");
193 MODULE_LICENSE("GPL v2");
194 

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