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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
23#define POLL_INTERVAL 3
24
25#define DEBOUNCE_COUNT 1
26
27
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
35struct 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
49static 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
62static 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
73static 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
106static 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, ®);
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
147static 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
199static const struct of_device_id ts4800_ts_of_match[] = {
200 { .compatible = "technologic,ts4800-ts", },
201 { },
202};
203MODULE_DEVICE_TABLE(of, ts4800_ts_of_match);
204
205static 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};
212module_platform_driver(ts4800_ts_driver);
213
214MODULE_AUTHOR("Damien Riegel <damien.riegel@savoirfairelinux.com>");
215MODULE_DESCRIPTION("TS-4800 Touchscreen Driver");
216MODULE_LICENSE("GPL v2");
217MODULE_ALIAS("platform:ts4800_ts");
218
