1 /*
2  * Touchscreen driver for the TS-4800 board
3  *
4  * Copyright (c) 2015 - Savoir-faire Linux
5  *
6  * This file is licensed under the terms of the GNU General Public
7  * License version 2. This program is licensed "as is" without any
8  * warranty of any kind, whether express or implied.
9  */
10 
11 #include <linux/bitops.h>
12 #include <linux/input.h>
13 #include <linux/input-polldev.h>
14 #include <linux/io.h>
15 #include <linux/kernel.h>
16 #include <linux/mfd/syscon.h>
17 #include <linux/module.h>
18 #include <linux/of.h>
19 #include <linux/platform_device.h>
20 #include <linux/regmap.h>
21 
22 /* polling interval in ms */
23 #define POLL_INTERVAL		3
24 
25 #define DEBOUNCE_COUNT		1
26 
27 /* sensor values are 12-bit wide */
28 #define MAX_12BIT		((1 << 12) - 1)
29 
30 #define PENDOWN_MASK		0x1
31 
32 #define X_OFFSET		0x0
33 #define Y_OFFSET		0x2
34 
35 struct ts4800_ts {
36 	struct input_polled_dev *poll_dev;
37 	struct device           *dev;
38 	char                    phys[32];
39 
40 	void __iomem            *base;
41 	struct regmap           *regmap;
42 	unsigned int            reg;
43 	unsigned int            bit;
44 
45 	bool                    pendown;
46 	int                     debounce;
47 };
48 
49 static void ts4800_ts_open(struct input_polled_dev *dev)
50 {
51 	struct ts4800_ts *ts = dev->private;
52 	int ret;
53 
54 	ts->pendown = false;
55 	ts->debounce = DEBOUNCE_COUNT;
56 
57 	ret = regmap_update_bits(ts->regmap, ts->reg, ts->bit, ts->bit);
58 	if (ret)
59 		dev_warn(ts->dev, "Failed to enable touchscreen\n");
60 }
61 
62 static void ts4800_ts_close(struct input_polled_dev *dev)
63 {
64 	struct ts4800_ts *ts = dev->private;
65 	int ret;
66 
67 	ret = regmap_update_bits(ts->regmap, ts->reg, ts->bit, 0);
68 	if (ret)
69 		dev_warn(ts->dev, "Failed to disable touchscreen\n");
70 
71 }
72 
73 static void ts4800_ts_poll(struct input_polled_dev *dev)
74 {
75 	struct input_dev *input_dev = dev->input;
76 	struct ts4800_ts *ts = dev->private;
77 	u16 last_x = readw(ts->base + X_OFFSET);
78 	u16 last_y = readw(ts->base + Y_OFFSET);
79 	bool pendown = last_x & PENDOWN_MASK;
80 
81 	if (pendown) {
82 		if (ts->debounce) {
83 			ts->debounce--;
84 			return;
85 		}
86 
87 		if (!ts->pendown) {
88 			input_report_key(input_dev, BTN_TOUCH, 1);
89 			ts->pendown = true;
90 		}
91 
92 		last_x = ((~last_x) >> 4) & MAX_12BIT;
93 		last_y = ((~last_y) >> 4) & MAX_12BIT;
94 
95 		input_report_abs(input_dev, ABS_X, last_x);
96 		input_report_abs(input_dev, ABS_Y, last_y);
97 		input_sync(input_dev);
98 	} else if (ts->pendown) {
99 		ts->pendown = false;
100 		ts->debounce = DEBOUNCE_COUNT;
101 		input_report_key(input_dev, BTN_TOUCH, 0);
102 		input_sync(input_dev);
103 	}
104 }
105 
106 static int ts4800_parse_dt(struct platform_device *pdev,
107 			   struct ts4800_ts *ts)
108 {
109 	struct device *dev = &pdev->dev;
110 	struct device_node *np = dev->of_node;
111 	struct device_node *syscon_np;
112 	u32 reg, bit;
113 	int error;
114 
115 	syscon_np = of_parse_phandle(np, "syscon", 0);
116 	if (!syscon_np) {
117 		dev_err(dev, "no syscon property\n");
118 		return -ENODEV;
119 	}
120 
121 	ts->regmap = syscon_node_to_regmap(syscon_np);
122 	of_node_put(syscon_np);
123 	if (IS_ERR(ts->regmap)) {
124 		dev_err(dev, "cannot get parent's regmap\n");
125 		return PTR_ERR(ts->regmap);
126 	}
127 
128 	error = of_property_read_u32_index(np, "syscon", 1, &reg);
129 	if (error < 0) {
130 		dev_err(dev, "no offset in syscon\n");
131 		return error;
132 	}
133 
134 	ts->reg = reg;
135 
136 	error = of_property_read_u32_index(np, "syscon", 2, &bit);
137 	if (error < 0) {
138 		dev_err(dev, "no bit in syscon\n");
139 		return error;
140 	}
141 
142 	ts->bit = BIT(bit);
143 
144 	return 0;
145 }
146 
147 static int ts4800_ts_probe(struct platform_device *pdev)
148 {
149 	struct input_polled_dev *poll_dev;
150 	struct ts4800_ts *ts;
151 	struct resource *res;
152 	int error;
153 
154 	ts = devm_kzalloc(&pdev->dev, sizeof(*ts), GFP_KERNEL);
155 	if (!ts)
156 		return -ENOMEM;
157 
158 	error = ts4800_parse_dt(pdev, ts);
159 	if (error)
160 		return error;
161 
162 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
163 	ts->base = devm_ioremap_resource(&pdev->dev, res);
164 	if (IS_ERR(ts->base))
165 		return PTR_ERR(ts->base);
166 
167 	poll_dev = devm_input_allocate_polled_device(&pdev->dev);
168 	if (!poll_dev)
169 		return -ENOMEM;
170 
171 	snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&pdev->dev));
172 	ts->poll_dev = poll_dev;
173 	ts->dev = &pdev->dev;
174 
175 	poll_dev->private = ts;
176 	poll_dev->poll_interval = POLL_INTERVAL;
177 	poll_dev->open = ts4800_ts_open;
178 	poll_dev->close = ts4800_ts_close;
179 	poll_dev->poll = ts4800_ts_poll;
180 
181 	poll_dev->input->name = "TS-4800 Touchscreen";
182 	poll_dev->input->phys = ts->phys;
183 
184 	input_set_capability(poll_dev->input, EV_KEY, BTN_TOUCH);
185 	input_set_abs_params(poll_dev->input, ABS_X, 0, MAX_12BIT, 0, 0);
186 	input_set_abs_params(poll_dev->input, ABS_Y, 0, MAX_12BIT, 0, 0);
187 
188 	error = input_register_polled_device(poll_dev);
189 	if (error) {
190 		dev_err(&pdev->dev,
191 			"Unabled to register polled input device (%d)\n",
192 			error);
193 		return error;
194 	}
195 
196 	return 0;
197 }
198 
199 static const struct of_device_id ts4800_ts_of_match[] = {
200 	{ .compatible = "technologic,ts4800-ts", },
201 	{ },
202 };
203 MODULE_DEVICE_TABLE(of, ts4800_ts_of_match);
204 
205 static struct platform_driver ts4800_ts_driver = {
206 	.driver = {
207 		.name = "ts4800-ts",
208 		.of_match_table = ts4800_ts_of_match,
209 	},
210 	.probe = ts4800_ts_probe,
211 };
212 module_platform_driver(ts4800_ts_driver);
213 
214 MODULE_AUTHOR("Damien Riegel <damien.riegel@savoirfairelinux.com>");
215 MODULE_DESCRIPTION("TS-4800 Touchscreen Driver");
216 MODULE_LICENSE("GPL v2");
217 MODULE_ALIAS("platform:ts4800_ts");
218