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 	data->edev.name = pdata->name;
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.dev.parent = &pdev->dev;
113 	data->edev.supported_cable = pdata->cable_names;
114 
115 	/* Check the length of array and set num_cables */
116 	for (i = 0; data->edev.supported_cable[i]; i++)
117 		;
118 	if (i == 0 || i > SUPPORTED_CABLE_MAX) {
119 		dev_err(&pdev->dev, "error: pdata->cable_names size = %d\n",
120 				i - 1);
121 		return -EINVAL;
122 	}
123 	data->num_cables = i;
124 
125 	if (!pdata->adc_conditions ||
126 			!pdata->adc_conditions[0].state) {
127 		dev_err(&pdev->dev, "error: adc_conditions not defined.\n");
128 		return -EINVAL;
129 	}
130 	data->adc_conditions = pdata->adc_conditions;
131 
132 	/* Check the length of array and set num_conditions */
133 	for (i = 0; data->adc_conditions[i].state; i++)
134 		;
135 	data->num_conditions = i;
136 
137 	data->chan = iio_channel_get(&pdev->dev, pdata->consumer_channel);
138 	if (IS_ERR(data->chan))
139 		return PTR_ERR(data->chan);
140 
141 	data->handling_delay = msecs_to_jiffies(pdata->handling_delay_ms);
142 
143 	INIT_DEFERRABLE_WORK(&data->handler, adc_jack_handler);
144 
145 	platform_set_drvdata(pdev, data);
146 
147 	err = devm_extcon_dev_register(&pdev->dev, &data->edev);
148 	if (err)
149 		return err;
150 
151 	data->irq = platform_get_irq(pdev, 0);
152 	if (!data->irq) {
153 		dev_err(&pdev->dev, "platform_get_irq failed\n");
154 		return -ENODEV;
155 	}
156 
157 	err = request_any_context_irq(data->irq, adc_jack_irq_thread,
158 			pdata->irq_flags, pdata->name, data);
159 
160 	if (err < 0) {
161 		dev_err(&pdev->dev, "error: irq %d\n", data->irq);
162 		return err;
163 	}
164 
165 	return 0;
166 }
167 
168 static int adc_jack_remove(struct platform_device *pdev)
169 {
170 	struct adc_jack_data *data = platform_get_drvdata(pdev);
171 
172 	free_irq(data->irq, data);
173 	cancel_work_sync(&data->handler.work);
174 
175 	return 0;
176 }
177 
178 static struct platform_driver adc_jack_driver = {
179 	.probe          = adc_jack_probe,
180 	.remove         = adc_jack_remove,
181 	.driver         = {
182 		.name   = "adc-jack",
183 		.owner  = THIS_MODULE,
184 	},
185 };
186 
187 module_platform_driver(adc_jack_driver);
188 
189 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
190 MODULE_DESCRIPTION("ADC Jack extcon driver");
191 MODULE_LICENSE("GPL v2");
192