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/io.h>
14 #include <linux/kernel.h>
15 #include <linux/mfd/syscon.h>
16 #include <linux/module.h>
17 #include <linux/of.h>
18 #include <linux/platform_device.h>
19 #include <linux/regmap.h>
20
21 /* polling interval in ms */
22 #define POLL_INTERVAL 3
23
24 #define DEBOUNCE_COUNT 1
25
26 /* sensor values are 12-bit wide */
27 #define MAX_12BIT ((1 << 12) - 1)
28
29 #define PENDOWN_MASK 0x1
30
31 #define X_OFFSET 0x0
32 #define Y_OFFSET 0x2
33
34 struct ts4800_ts {
35 struct input_dev *input;
36 struct device *dev;
37 char phys[32];
38
39 void __iomem *base;
40 struct regmap *regmap;
41 unsigned int reg;
42 unsigned int bit;
43
44 bool pendown;
45 int debounce;
46 };
47
ts4800_ts_open(struct input_dev * input_dev)48 static int ts4800_ts_open(struct input_dev *input_dev)
49 {
50 struct ts4800_ts *ts = input_get_drvdata(input_dev);
51 int error;
52
53 ts->pendown = false;
54 ts->debounce = DEBOUNCE_COUNT;
55
56 error = regmap_update_bits(ts->regmap, ts->reg, ts->bit, ts->bit);
57 if (error) {
58 dev_warn(ts->dev, "Failed to enable touchscreen: %d\n", error);
59 return error;
60 }
61
62 return 0;
63 }
64
ts4800_ts_close(struct input_dev * input_dev)65 static void ts4800_ts_close(struct input_dev *input_dev)
66 {
67 struct ts4800_ts *ts = input_get_drvdata(input_dev);
68 int ret;
69
70 ret = regmap_update_bits(ts->regmap, ts->reg, ts->bit, 0);
71 if (ret)
72 dev_warn(ts->dev, "Failed to disable touchscreen\n");
73
74 }
75
ts4800_ts_poll(struct input_dev * input_dev)76 static void ts4800_ts_poll(struct input_dev *input_dev)
77 {
78 struct ts4800_ts *ts = input_get_drvdata(input_dev);
79 u16 last_x = readw(ts->base + X_OFFSET);
80 u16 last_y = readw(ts->base + Y_OFFSET);
81 bool pendown = last_x & PENDOWN_MASK;
82
83 if (pendown) {
84 if (ts->debounce) {
85 ts->debounce--;
86 return;
87 }
88
89 if (!ts->pendown) {
90 input_report_key(input_dev, BTN_TOUCH, 1);
91 ts->pendown = true;
92 }
93
94 last_x = ((~last_x) >> 4) & MAX_12BIT;
95 last_y = ((~last_y) >> 4) & MAX_12BIT;
96
97 input_report_abs(input_dev, ABS_X, last_x);
98 input_report_abs(input_dev, ABS_Y, last_y);
99 input_sync(input_dev);
100 } else if (ts->pendown) {
101 ts->pendown = false;
102 ts->debounce = DEBOUNCE_COUNT;
103 input_report_key(input_dev, BTN_TOUCH, 0);
104 input_sync(input_dev);
105 }
106 }
107
ts4800_parse_dt(struct platform_device * pdev,struct ts4800_ts * ts)108 static int ts4800_parse_dt(struct platform_device *pdev,
109 struct ts4800_ts *ts)
110 {
111 struct device *dev = &pdev->dev;
112 struct device_node *np = dev->of_node;
113 struct device_node *syscon_np;
114 u32 reg, bit;
115 int error;
116
117 syscon_np = of_parse_phandle(np, "syscon", 0);
118 if (!syscon_np) {
119 dev_err(dev, "no syscon property\n");
120 return -ENODEV;
121 }
122
123 ts->regmap = syscon_node_to_regmap(syscon_np);
124 of_node_put(syscon_np);
125 if (IS_ERR(ts->regmap)) {
126 dev_err(dev, "cannot get parent's regmap\n");
127 return PTR_ERR(ts->regmap);
128 }
129
130 error = of_property_read_u32_index(np, "syscon", 1, ®);
131 if (error < 0) {
132 dev_err(dev, "no offset in syscon\n");
133 return error;
134 }
135
136 ts->reg = reg;
137
138 error = of_property_read_u32_index(np, "syscon", 2, &bit);
139 if (error < 0) {
140 dev_err(dev, "no bit in syscon\n");
141 return error;
142 }
143
144 ts->bit = BIT(bit);
145
146 return 0;
147 }
148
ts4800_ts_probe(struct platform_device * pdev)149 static int ts4800_ts_probe(struct platform_device *pdev)
150 {
151 struct input_dev *input_dev;
152 struct ts4800_ts *ts;
153 int error;
154
155 ts = devm_kzalloc(&pdev->dev, sizeof(*ts), GFP_KERNEL);
156 if (!ts)
157 return -ENOMEM;
158
159 error = ts4800_parse_dt(pdev, ts);
160 if (error)
161 return error;
162
163 ts->base = devm_platform_ioremap_resource(pdev, 0);
164 if (IS_ERR(ts->base))
165 return PTR_ERR(ts->base);
166
167 input_dev = devm_input_allocate_device(&pdev->dev);
168 if (!input_dev)
169 return -ENOMEM;
170
171 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&pdev->dev));
172 ts->input = input_dev;
173 ts->dev = &pdev->dev;
174
175 input_set_drvdata(input_dev, ts);
176
177 input_dev->name = "TS-4800 Touchscreen";
178 input_dev->phys = ts->phys;
179
180 input_dev->open = ts4800_ts_open;
181 input_dev->close = ts4800_ts_close;
182
183 input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
184 input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0);
185 input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
186
187 error = input_setup_polling(input_dev, ts4800_ts_poll);
188 if (error) {
189 dev_err(&pdev->dev, "Unable to set up polling: %d\n", error);
190 return error;
191 }
192
193 input_set_poll_interval(input_dev, POLL_INTERVAL);
194
195 error = input_register_device(input_dev);
196 if (error) {
197 dev_err(&pdev->dev,
198 "Unable to register input device: %d\n", error);
199 return error;
200 }
201
202 return 0;
203 }
204
205 static const struct of_device_id ts4800_ts_of_match[] = {
206 { .compatible = "technologic,ts4800-ts", },
207 { },
208 };
209 MODULE_DEVICE_TABLE(of, ts4800_ts_of_match);
210
211 static struct platform_driver ts4800_ts_driver = {
212 .driver = {
213 .name = "ts4800-ts",
214 .of_match_table = ts4800_ts_of_match,
215 },
216 .probe = ts4800_ts_probe,
217 };
218 module_platform_driver(ts4800_ts_driver);
219
220 MODULE_AUTHOR("Damien Riegel <damien.riegel@savoirfairelinux.com>");
221 MODULE_DESCRIPTION("TS-4800 Touchscreen Driver");
222 MODULE_LICENSE("GPL v2");
223 MODULE_ALIAS("platform:ts4800_ts");
224