summaryrefslogtreecommitdiffstats
path: root/drivers/input/touchscreen/mc13783_ts.c
blob: ef64f36c5ffc37ff87e3f498a556a5a3fe543c7c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
/*
 * Driver for the Freescale Semiconductor MC13783 touchscreen.
 *
 * Copyright 2004-2007 Freescale Semiconductor, Inc. All Rights Reserved.
 * Copyright (C) 2009 Sascha Hauer, Pengutronix
 *
 * Initial development of this code was funded by
 * Phytec Messtechnik GmbH, http://www.phytec.de/
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 */
#include <linux/platform_device.h>
#include <linux/mfd/mc13783.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/input.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/init.h>

#define MC13783_TS_NAME	"mc13783-ts"

#define DEFAULT_SAMPLE_TOLERANCE 300

static unsigned int sample_tolerance = DEFAULT_SAMPLE_TOLERANCE;
module_param(sample_tolerance, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(sample_tolerance,
		"If the minimal and maximal value read out for one axis (out "
		"of three) differ by this value (default: "
		__stringify(DEFAULT_SAMPLE_TOLERANCE) ") or more, the reading "
		"is supposed to be wrong and is discarded.  Set to 0 to "
		"disable this check.");

struct mc13783_ts_priv {
	struct input_dev *idev;
	struct mc13xxx *mc13xxx;
	struct delayed_work work;
	unsigned int sample[4];
	struct mc13xxx_ts_platform_data *touch;
};

static irqreturn_t mc13783_ts_handler(int irq, void *data)
{
	struct mc13783_ts_priv *priv = data;

	mc13xxx_irq_ack(priv->mc13xxx, irq);

	/*
	 * Kick off reading coordinates. Note that if work happens already
	 * be queued for future execution (it rearms itself) it will not
	 * be rescheduled for immediate execution here. However the rearm
	 * delay is HZ / 50 which is acceptable.
	 */
	schedule_delayed_work(&priv->work, 0);

	return IRQ_HANDLED;
}

#define sort3(a0, a1, a2) ({						\
		if (a0 > a1)						\
			swap(a0, a1);					\
		if (a1 > a2)						\
			swap(a1, a2);					\
		if (a0 > a1)						\
			swap(a0, a1);					\
		})

static void mc13783_ts_report_sample(struct mc13783_ts_priv *priv)
{
	struct input_dev *idev = priv->idev;
	int x0, x1, x2, y0, y1, y2;
	int cr0, cr1;

	/*
	 * the values are 10-bit wide only, but the two least significant
	 * bits are for future 12 bit use and reading yields 0
	 */
	x0 = priv->sample[0] & 0xfff;
	x1 = priv->sample[1] & 0xfff;
	x2 = priv->sample[2] & 0xfff;
	y0 = priv->sample[3] & 0xfff;
	y1 = (priv->sample[0] >> 12) & 0xfff;
	y2 = (priv->sample[1] >> 12) & 0xfff;
	cr0 = (priv->sample[2] >> 12) & 0xfff;
	cr1 = (priv->sample[3] >> 12) & 0xfff;

	dev_dbg(&idev->dev,
		"x: (% 4d,% 4d,% 4d) y: (% 4d, % 4d,% 4d) cr: (% 4d, % 4d)\n",
		x0, x1, x2, y0, y1, y2, cr0, cr1);

	sort3(x0, x1, x2);
	sort3(y0, y1, y2);

	cr0 = (cr0 + cr1) / 2;

	if (!cr0 || !sample_tolerance ||
			(x2 - x0 < sample_tolerance &&
			 y2 - y0 < sample_tolerance)) {
		/* report the median coordinate and average pressure */
		if (cr0) {
			input_report_abs(idev, ABS_X, x1);
			input_report_abs(idev, ABS_Y, y1);

			dev_dbg(&idev->dev, "report (%d, %d, %d)\n",
					x1, y1, 0x1000 - cr0);
			schedule_delayed_work(&priv->work, HZ / 50);
		} else {
			dev_dbg(&idev->dev, "report release\n");
		}

		input_report_abs(idev, ABS_PRESSURE,
				cr0 ? 0x1000 - cr0 : cr0);
		input_report_key(idev, BTN_TOUCH, cr0);
		input_sync(idev);
	} else {
		dev_dbg(&idev->dev, "discard event\n");
	}
}

static void mc13783_ts_work(struct work_struct *work)
{
	struct mc13783_ts_priv *priv =
		container_of(work, struct mc13783_ts_priv, work.work);
	unsigned int mode = MC13XXX_ADC_MODE_TS;
	unsigned int channel = 12;

	if (mc13xxx_adc_do_conversion(priv->mc13xxx,
				mode, channel,
				priv->touch->ato, priv->touch->atox,
				priv->sample) == 0)
		mc13783_ts_report_sample(priv);
}

static int mc13783_ts_open(struct input_dev *dev)
{
	struct mc13783_ts_priv *priv = input_get_drvdata(dev);
	int ret;

	mc13xxx_lock(priv->mc13xxx);

	mc13xxx_irq_ack(priv->mc13xxx, MC13XXX_IRQ_TS);

	ret = mc13xxx_irq_request(priv->mc13xxx, MC13XXX_IRQ_TS,
		mc13783_ts_handler, MC13783_TS_NAME, priv);
	if (ret)
		goto out;

	ret = mc13xxx_reg_rmw(priv->mc13xxx, MC13XXX_ADC0,
			MC13XXX_ADC0_TSMOD_MASK, MC13XXX_ADC0_TSMOD0);
	if (ret)
		mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_TS, priv);
out:
	mc13xxx_unlock(priv->mc13xxx);
	return ret;
}

static void mc13783_ts_close(struct input_dev *dev)
{
	struct mc13783_ts_priv *priv = input_get_drvdata(dev);

	mc13xxx_lock(priv->mc13xxx);
	mc13xxx_reg_rmw(priv->mc13xxx, MC13XXX_ADC0,
			MC13XXX_ADC0_TSMOD_MASK, 0);
	mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_TS, priv);
	mc13xxx_unlock(priv->mc13xxx);

	cancel_delayed_work_sync(&priv->work);
}

static int __init mc13783_ts_probe(struct platform_device *pdev)
{
	struct mc13783_ts_priv *priv;
	struct input_dev *idev;
	int ret = -ENOMEM;

	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
	idev = input_allocate_device();
	if (!priv || !idev)
		goto err_free_mem;

	INIT_DELAYED_WORK(&priv->work, mc13783_ts_work);
	priv->mc13xxx = dev_get_drvdata(pdev->dev.parent);
	priv->idev = idev;
	priv->touch = dev_get_platdata(&pdev->dev);
	if (!priv->touch) {
		dev_err(&pdev->dev, "missing platform data\n");
		ret = -ENODEV;
		goto err_free_mem;
	}

	idev->name = MC13783_TS_NAME;
	idev->dev.parent = &pdev->dev;

	idev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
	idev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
	input_set_abs_params(idev, ABS_X, 0, 0xfff, 0, 0);
	input_set_abs_params(idev, ABS_Y, 0, 0xfff, 0, 0);
	input_set_abs_params(idev, ABS_PRESSURE, 0, 0xfff, 0, 0);

	idev->open = mc13783_ts_open;
	idev->close = mc13783_ts_close;

	input_set_drvdata(idev, priv);

	ret = input_register_device(priv->idev);
	if (ret) {
		dev_err(&pdev->dev,
			"register input device failed with %d\n", ret);
		goto err_free_mem;
	}

	platform_set_drvdata(pdev, priv);
	return 0;

err_free_mem:
	input_free_device(idev);
	kfree(priv);
	return ret;
}

static int mc13783_ts_remove(struct platform_device *pdev)
{
	struct mc13783_ts_priv *priv = platform_get_drvdata(pdev);

	input_unregister_device(priv->idev);
	kfree(priv);

	return 0;
}

static struct platform_driver mc13783_ts_driver = {
	.remove		= mc13783_ts_remove,
	.driver		= {
		.name	= MC13783_TS_NAME,
	},
};

module_platform_driver_probe(mc13783_ts_driver, mc13783_ts_probe);

MODULE_DESCRIPTION("MC13783 input touchscreen driver");
MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:" MC13783_TS_NAME);