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7e577a17 AI |
1 | /* |
2 | * Driver for I2C connected EETI EXC3000 multiple touch controller | |
3 | * | |
4 | * Copyright (C) 2017 Ahmet Inan <inan@distec.de> | |
5 | * | |
6 | * minimal implementation based on egalax_ts.c and egalax_i2c.c | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | */ | |
12 | ||
13 | #include <linux/bitops.h> | |
14 | #include <linux/device.h> | |
15 | #include <linux/i2c.h> | |
16 | #include <linux/input.h> | |
17 | #include <linux/input/mt.h> | |
18 | #include <linux/input/touchscreen.h> | |
19 | #include <linux/interrupt.h> | |
20 | #include <linux/module.h> | |
21 | #include <linux/of.h> | |
22 | #include <linux/timer.h> | |
23 | #include <asm/unaligned.h> | |
24 | ||
25 | #define EXC3000_NUM_SLOTS 10 | |
26 | #define EXC3000_SLOTS_PER_FRAME 5 | |
27 | #define EXC3000_LEN_FRAME 66 | |
28 | #define EXC3000_LEN_POINT 10 | |
29 | #define EXC3000_MT_EVENT 6 | |
30 | #define EXC3000_TIMEOUT_MS 100 | |
31 | ||
32 | struct exc3000_data { | |
33 | struct i2c_client *client; | |
34 | struct input_dev *input; | |
35 | struct touchscreen_properties prop; | |
36 | struct timer_list timer; | |
37 | u8 buf[2 * EXC3000_LEN_FRAME]; | |
38 | }; | |
39 | ||
40 | static void exc3000_report_slots(struct input_dev *input, | |
41 | struct touchscreen_properties *prop, | |
42 | const u8 *buf, int num) | |
43 | { | |
44 | for (; num--; buf += EXC3000_LEN_POINT) { | |
45 | if (buf[0] & BIT(0)) { | |
46 | input_mt_slot(input, buf[1]); | |
47 | input_mt_report_slot_state(input, MT_TOOL_FINGER, true); | |
48 | touchscreen_report_pos(input, prop, | |
49 | get_unaligned_le16(buf + 2), | |
50 | get_unaligned_le16(buf + 4), | |
51 | true); | |
52 | } | |
53 | } | |
54 | } | |
55 | ||
56 | static void exc3000_timer(struct timer_list *t) | |
57 | { | |
58 | struct exc3000_data *data = from_timer(data, t, timer); | |
59 | ||
60 | input_mt_sync_frame(data->input); | |
61 | input_sync(data->input); | |
62 | } | |
63 | ||
64 | static int exc3000_read_frame(struct i2c_client *client, u8 *buf) | |
65 | { | |
66 | int ret; | |
67 | ||
68 | ret = i2c_master_send(client, "'", 2); | |
69 | if (ret < 0) | |
70 | return ret; | |
71 | ||
72 | if (ret != 2) | |
73 | return -EIO; | |
74 | ||
75 | ret = i2c_master_recv(client, buf, EXC3000_LEN_FRAME); | |
76 | if (ret < 0) | |
77 | return ret; | |
78 | ||
79 | if (ret != EXC3000_LEN_FRAME) | |
80 | return -EIO; | |
81 | ||
82 | if (get_unaligned_le16(buf) != EXC3000_LEN_FRAME || | |
83 | buf[2] != EXC3000_MT_EVENT) | |
84 | return -EINVAL; | |
85 | ||
86 | return 0; | |
87 | } | |
88 | ||
89 | static int exc3000_read_data(struct i2c_client *client, | |
90 | u8 *buf, int *n_slots) | |
91 | { | |
92 | int error; | |
93 | ||
94 | error = exc3000_read_frame(client, buf); | |
95 | if (error) | |
96 | return error; | |
97 | ||
98 | *n_slots = buf[3]; | |
99 | if (!*n_slots || *n_slots > EXC3000_NUM_SLOTS) | |
100 | return -EINVAL; | |
101 | ||
102 | if (*n_slots > EXC3000_SLOTS_PER_FRAME) { | |
103 | /* Read 2nd frame to get the rest of the contacts. */ | |
104 | error = exc3000_read_frame(client, buf + EXC3000_LEN_FRAME); | |
105 | if (error) | |
106 | return error; | |
107 | ||
108 | /* 2nd chunk must have number of contacts set to 0. */ | |
109 | if (buf[EXC3000_LEN_FRAME + 3] != 0) | |
110 | return -EINVAL; | |
111 | } | |
112 | ||
113 | return 0; | |
114 | } | |
115 | ||
116 | static irqreturn_t exc3000_interrupt(int irq, void *dev_id) | |
117 | { | |
118 | struct exc3000_data *data = dev_id; | |
119 | struct input_dev *input = data->input; | |
120 | u8 *buf = data->buf; | |
121 | int slots, total_slots; | |
122 | int error; | |
123 | ||
124 | error = exc3000_read_data(data->client, buf, &total_slots); | |
125 | if (error) { | |
126 | /* Schedule a timer to release "stuck" contacts */ | |
127 | mod_timer(&data->timer, | |
128 | jiffies + msecs_to_jiffies(EXC3000_TIMEOUT_MS)); | |
129 | goto out; | |
130 | } | |
131 | ||
132 | /* | |
133 | * We read full state successfully, no contacts will be "stuck". | |
134 | */ | |
135 | del_timer_sync(&data->timer); | |
136 | ||
137 | while (total_slots > 0) { | |
138 | slots = min(total_slots, EXC3000_SLOTS_PER_FRAME); | |
139 | exc3000_report_slots(input, &data->prop, buf + 4, slots); | |
140 | total_slots -= slots; | |
141 | buf += EXC3000_LEN_FRAME; | |
142 | } | |
143 | ||
144 | input_mt_sync_frame(input); | |
145 | input_sync(input); | |
146 | ||
147 | out: | |
148 | return IRQ_HANDLED; | |
149 | } | |
150 | ||
151 | static int exc3000_probe(struct i2c_client *client, | |
152 | const struct i2c_device_id *id) | |
153 | { | |
154 | struct exc3000_data *data; | |
155 | struct input_dev *input; | |
156 | int error; | |
157 | ||
158 | data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL); | |
159 | if (!data) | |
160 | return -ENOMEM; | |
161 | ||
162 | data->client = client; | |
163 | timer_setup(&data->timer, exc3000_timer, 0); | |
164 | ||
165 | input = devm_input_allocate_device(&client->dev); | |
166 | if (!input) | |
167 | return -ENOMEM; | |
168 | ||
169 | data->input = input; | |
170 | ||
171 | input->name = "EETI EXC3000 Touch Screen"; | |
172 | input->id.bustype = BUS_I2C; | |
173 | ||
174 | input_set_abs_params(input, ABS_MT_POSITION_X, 0, 4095, 0, 0); | |
175 | input_set_abs_params(input, ABS_MT_POSITION_Y, 0, 4095, 0, 0); | |
176 | touchscreen_parse_properties(input, true, &data->prop); | |
177 | ||
178 | error = input_mt_init_slots(input, EXC3000_NUM_SLOTS, | |
179 | INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED); | |
180 | if (error) | |
181 | return error; | |
182 | ||
183 | error = input_register_device(input); | |
184 | if (error) | |
185 | return error; | |
186 | ||
187 | error = devm_request_threaded_irq(&client->dev, client->irq, | |
188 | NULL, exc3000_interrupt, IRQF_ONESHOT, | |
189 | client->name, data); | |
190 | if (error) | |
191 | return error; | |
192 | ||
193 | return 0; | |
194 | } | |
195 | ||
196 | static const struct i2c_device_id exc3000_id[] = { | |
197 | { "exc3000", 0 }, | |
198 | { } | |
199 | }; | |
200 | MODULE_DEVICE_TABLE(i2c, exc3000_id); | |
201 | ||
202 | #ifdef CONFIG_OF | |
203 | static const struct of_device_id exc3000_of_match[] = { | |
204 | { .compatible = "eeti,exc3000" }, | |
205 | { } | |
206 | }; | |
207 | MODULE_DEVICE_TABLE(of, exc3000_of_match); | |
208 | #endif | |
209 | ||
210 | static struct i2c_driver exc3000_driver = { | |
211 | .driver = { | |
212 | .name = "exc3000", | |
213 | .of_match_table = of_match_ptr(exc3000_of_match), | |
214 | }, | |
215 | .id_table = exc3000_id, | |
216 | .probe = exc3000_probe, | |
217 | }; | |
218 | ||
219 | module_i2c_driver(exc3000_driver); | |
220 | ||
221 | MODULE_AUTHOR("Ahmet Inan <inan@distec.de>"); | |
222 | MODULE_DESCRIPTION("I2C connected EETI EXC3000 multiple touch controller driver"); | |
223 | MODULE_LICENSE("GPL v2"); |