summaryrefslogtreecommitdiff
path: root/drivers/input/touchscreen/ts4800-ts.c
blob: fed73eeb47b3c6e263ca2e0415d9b385cc2f4854 (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
/*
 * Touchscreen driver for the TS-4800 board
 *
 * Copyright (c) 2015 - Savoir-faire Linux
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/bitops.h>
#include <linux/input.h>
#include <linux/input-polldev.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>

/* polling interval in ms */
#define POLL_INTERVAL		3

#define DEBOUNCE_COUNT		1

/* sensor values are 12-bit wide */
#define MAX_12BIT		((1 << 12) - 1)

#define PENDOWN_MASK		0x1

#define X_OFFSET		0x0
#define Y_OFFSET		0x2

struct ts4800_ts {
	struct input_polled_dev *poll_dev;
	struct device           *dev;
	char                    phys[32];

	void __iomem            *base;
	struct regmap           *regmap;
	unsigned int            reg;
	unsigned int            bit;

	bool                    pendown;
	int                     debounce;
};

static void ts4800_ts_open(struct input_polled_dev *dev)
{
	struct ts4800_ts *ts = dev->private;
	int ret;

	ts->pendown = false;
	ts->debounce = DEBOUNCE_COUNT;

	ret = regmap_update_bits(ts->regmap, ts->reg, ts->bit, ts->bit);
	if (ret)
		dev_warn(ts->dev, "Failed to enable touchscreen\n");
}

static void ts4800_ts_close(struct input_polled_dev *dev)
{
	struct ts4800_ts *ts = dev->private;
	int ret;

	ret = regmap_update_bits(ts->regmap, ts->reg, ts->bit, 0);
	if (ret)
		dev_warn(ts->dev, "Failed to disable touchscreen\n");

}

static void ts4800_ts_poll(struct input_polled_dev *dev)
{
	struct input_dev *input_dev = dev->input;
	struct ts4800_ts *ts = dev->private;
	u16 last_x = readw(ts->base + X_OFFSET);
	u16 last_y = readw(ts->base + Y_OFFSET);
	bool pendown = last_x & PENDOWN_MASK;

	if (pendown) {
		if (ts->debounce) {
			ts->debounce--;
			return;
		}

		if (!ts->pendown) {
			input_report_key(input_dev, BTN_TOUCH, 1);
			ts->pendown = true;
		}

		last_x = ((~last_x) >> 4) & MAX_12BIT;
		last_y = ((~last_y) >> 4) & MAX_12BIT;

		input_report_abs(input_dev, ABS_X, last_x);
		input_report_abs(input_dev, ABS_Y, last_y);
		input_sync(input_dev);
	} else if (ts->pendown) {
		ts->pendown = false;
		ts->debounce = DEBOUNCE_COUNT;
		input_report_key(input_dev, BTN_TOUCH, 0);
		input_sync(input_dev);
	}
}

static int ts4800_parse_dt(struct platform_device *pdev,
			   struct ts4800_ts *ts)
{
	struct device *dev = &pdev->dev;
	struct device_node *np = dev->of_node;
	struct device_node *syscon_np;
	u32 reg, bit;
	int error;

	syscon_np = of_parse_phandle(np, "syscon", 0);
	if (!syscon_np) {
		dev_err(dev, "no syscon property\n");
		return -ENODEV;
	}

	ts->regmap = syscon_node_to_regmap(syscon_np);
	of_node_put(syscon_np);
	if (IS_ERR(ts->regmap)) {
		dev_err(dev, "cannot get parent's regmap\n");
		return PTR_ERR(ts->regmap);
	}

	error = of_property_read_u32_index(np, "syscon", 1, &reg);
	if (error < 0) {
		dev_err(dev, "no offset in syscon\n");
		return error;
	}

	ts->reg = reg;

	error = of_property_read_u32_index(np, "syscon", 2, &bit);
	if (error < 0) {
		dev_err(dev, "no bit in syscon\n");
		return error;
	}

	ts->bit = BIT(bit);

	return 0;
}

static int ts4800_ts_probe(struct platform_device *pdev)
{
	struct input_polled_dev *poll_dev;
	struct ts4800_ts *ts;
	struct resource *res;
	int error;

	ts = devm_kzalloc(&pdev->dev, sizeof(*ts), GFP_KERNEL);
	if (!ts)
		return -ENOMEM;

	error = ts4800_parse_dt(pdev, ts);
	if (error)
		return error;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	ts->base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(ts->base))
		return PTR_ERR(ts->base);

	poll_dev = devm_input_allocate_polled_device(&pdev->dev);
	if (!poll_dev)
		return -ENOMEM;

	snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&pdev->dev));
	ts->poll_dev = poll_dev;
	ts->dev = &pdev->dev;

	poll_dev->private = ts;
	poll_dev->poll_interval = POLL_INTERVAL;
	poll_dev->open = ts4800_ts_open;
	poll_dev->close = ts4800_ts_close;
	poll_dev->poll = ts4800_ts_poll;

	poll_dev->input->name = "TS-4800 Touchscreen";
	poll_dev->input->phys = ts->phys;

	input_set_capability(poll_dev->input, EV_KEY, BTN_TOUCH);
	input_set_abs_params(poll_dev->input, ABS_X, 0, MAX_12BIT, 0, 0);
	input_set_abs_params(poll_dev->input, ABS_Y, 0, MAX_12BIT, 0, 0);

	error = input_register_polled_device(poll_dev);
	if (error) {
		dev_err(&pdev->dev,
			"Unabled to register polled input device (%d)\n",
			error);
		return error;
	}

	return 0;
}

static const struct of_device_id ts4800_ts_of_match[] = {
	{ .compatible = "technologic,ts4800-ts", },
	{ },
};
MODULE_DEVICE_TABLE(of, ts4800_ts_of_match);

static struct platform_driver ts4800_ts_driver = {
	.driver = {
		.name = "ts4800-ts",
		.of_match_table = ts4800_ts_of_match,
	},
	.probe = ts4800_ts_probe,
};
module_platform_driver(ts4800_ts_driver);

MODULE_AUTHOR("Damien Riegel <damien.riegel@savoirfairelinux.com>");
MODULE_DESCRIPTION("TS-4800 Touchscreen Driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:ts4800_ts");