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 char **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 	data->edev->name = pdata->name;
114 
115 	if (!pdata->adc_conditions ||
116 			!pdata->adc_conditions[0].state) {
117 		dev_err(&pdev->dev, "error: adc_conditions not defined.\n");
118 		return -EINVAL;
119 	}
120 	data->adc_conditions = pdata->adc_conditions;
121 
122 	/* Check the length of array and set num_conditions */
123 	for (i = 0; data->adc_conditions[i].state; i++)
124 		;
125 	data->num_conditions = i;
126 
127 	data->chan = iio_channel_get(&pdev->dev, pdata->consumer_channel);
128 	if (IS_ERR(data->chan))
129 		return PTR_ERR(data->chan);
130 
131 	data->handling_delay = msecs_to_jiffies(pdata->handling_delay_ms);
132 
133 	INIT_DEFERRABLE_WORK(&data->handler, adc_jack_handler);
134 
135 	platform_set_drvdata(pdev, data);
136 
137 	err = devm_extcon_dev_register(&pdev->dev, data->edev);
138 	if (err)
139 		return err;
140 
141 	data->irq = platform_get_irq(pdev, 0);
142 	if (!data->irq) {
143 		dev_err(&pdev->dev, "platform_get_irq failed\n");
144 		return -ENODEV;
145 	}
146 
147 	err = request_any_context_irq(data->irq, adc_jack_irq_thread,
148 			pdata->irq_flags, pdata->name, data);
149 
150 	if (err < 0) {
151 		dev_err(&pdev->dev, "error: irq %d\n", data->irq);
152 		return err;
153 	}
154 
155 	return 0;
156 }
157 
158 static int adc_jack_remove(struct platform_device *pdev)
159 {
160 	struct adc_jack_data *data = platform_get_drvdata(pdev);
161 
162 	free_irq(data->irq, data);
163 	cancel_work_sync(&data->handler.work);
164 	iio_channel_release(data->chan);
165 
166 	return 0;
167 }
168 
169 static struct platform_driver adc_jack_driver = {
170 	.probe          = adc_jack_probe,
171 	.remove         = adc_jack_remove,
172 	.driver         = {
173 		.name   = "adc-jack",
174 	},
175 };
176 
177 module_platform_driver(adc_jack_driver);
178 
179 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
180 MODULE_DESCRIPTION("ADC Jack extcon driver");
181 MODULE_LICENSE("GPL v2");
182