1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * Copyright (C) 2023 Anshul Dalal <anshulusr@gmail.com> |
4 | * |
5 | * Driver for Adafruit Mini I2C Gamepad |
6 | * |
7 | * Based on the work of: |
8 | * Oleh Kravchenko (Sparkfun Qwiic Joystick driver) |
9 | * |
10 | * Datasheet: https://cdn-learn.adafruit.com/downloads/pdf/gamepad-qt.pdf |
11 | * Product page: https://www.adafruit.com/product/5743 |
12 | * Firmware and hardware sources: https://github.com/adafruit/Adafruit_Seesaw |
13 | * |
14 | * TODO: |
15 | * - Add interrupt support |
16 | */ |
17 | |
18 | #include <asm/unaligned.h> |
19 | #include <linux/bits.h> |
20 | #include <linux/delay.h> |
21 | #include <linux/i2c.h> |
22 | #include <linux/input.h> |
23 | #include <linux/input/sparse-keymap.h> |
24 | #include <linux/kernel.h> |
25 | #include <linux/module.h> |
26 | |
27 | #define SEESAW_DEVICE_NAME "seesaw-gamepad" |
28 | |
29 | #define SEESAW_ADC_BASE 0x0900 |
30 | |
31 | #define SEESAW_GPIO_DIRCLR_BULK 0x0103 |
32 | #define SEESAW_GPIO_BULK 0x0104 |
33 | #define SEESAW_GPIO_BULK_SET 0x0105 |
34 | #define SEESAW_GPIO_PULLENSET 0x010b |
35 | |
36 | #define SEESAW_STATUS_HW_ID 0x0001 |
37 | #define SEESAW_STATUS_SWRST 0x007f |
38 | |
39 | #define SEESAW_ADC_OFFSET 0x07 |
40 | |
41 | #define SEESAW_BUTTON_A 0x05 |
42 | #define SEESAW_BUTTON_B 0x01 |
43 | #define SEESAW_BUTTON_X 0x06 |
44 | #define SEESAW_BUTTON_Y 0x02 |
45 | #define SEESAW_BUTTON_START 0x10 |
46 | #define SEESAW_BUTTON_SELECT 0x00 |
47 | |
48 | #define SEESAW_ANALOG_X 0x0e |
49 | #define SEESAW_ANALOG_Y 0x0f |
50 | |
51 | #define SEESAW_JOYSTICK_MAX_AXIS 1023 |
52 | #define SEESAW_JOYSTICK_FUZZ 2 |
53 | #define SEESAW_JOYSTICK_FLAT 4 |
54 | |
55 | #define SEESAW_GAMEPAD_POLL_INTERVAL_MS 16 |
56 | #define SEESAW_GAMEPAD_POLL_MIN 8 |
57 | #define SEESAW_GAMEPAD_POLL_MAX 32 |
58 | |
59 | static const unsigned long SEESAW_BUTTON_MASK = |
60 | BIT(SEESAW_BUTTON_A) | BIT(SEESAW_BUTTON_B) | BIT(SEESAW_BUTTON_X) | |
61 | BIT(SEESAW_BUTTON_Y) | BIT(SEESAW_BUTTON_START) | |
62 | BIT(SEESAW_BUTTON_SELECT); |
63 | |
64 | struct seesaw_gamepad { |
65 | struct input_dev *input_dev; |
66 | struct i2c_client *i2c_client; |
67 | }; |
68 | |
69 | struct seesaw_data { |
70 | u16 x; |
71 | u16 y; |
72 | u32 button_state; |
73 | }; |
74 | |
75 | static const struct key_entry seesaw_buttons_new[] = { |
76 | { KE_KEY, SEESAW_BUTTON_A, .keycode = BTN_SOUTH }, |
77 | { KE_KEY, SEESAW_BUTTON_B, .keycode = BTN_EAST }, |
78 | { KE_KEY, SEESAW_BUTTON_X, .keycode = BTN_NORTH }, |
79 | { KE_KEY, SEESAW_BUTTON_Y, .keycode = BTN_WEST }, |
80 | { KE_KEY, SEESAW_BUTTON_START, .keycode = BTN_START }, |
81 | { KE_KEY, SEESAW_BUTTON_SELECT, .keycode = BTN_SELECT }, |
82 | { KE_END, 0 } |
83 | }; |
84 | |
85 | static int seesaw_register_read(struct i2c_client *client, u16 reg, void *buf, |
86 | int count) |
87 | { |
88 | __be16 register_buf = cpu_to_be16(reg); |
89 | struct i2c_msg message_buf[2] = { |
90 | { |
91 | .addr = client->addr, |
92 | .flags = client->flags, |
93 | .len = sizeof(register_buf), |
94 | .buf = (u8 *)®ister_buf, |
95 | }, |
96 | { |
97 | .addr = client->addr, |
98 | .flags = client->flags | I2C_M_RD, |
99 | .len = count, |
100 | .buf = (u8 *)buf, |
101 | }, |
102 | }; |
103 | int ret; |
104 | |
105 | ret = i2c_transfer(adap: client->adapter, msgs: message_buf, |
106 | ARRAY_SIZE(message_buf)); |
107 | if (ret < 0) |
108 | return ret; |
109 | |
110 | return 0; |
111 | } |
112 | |
113 | static int seesaw_register_write_u8(struct i2c_client *client, u16 reg, |
114 | u8 value) |
115 | { |
116 | u8 write_buf[sizeof(reg) + sizeof(value)]; |
117 | int ret; |
118 | |
119 | put_unaligned_be16(val: reg, p: write_buf); |
120 | write_buf[sizeof(reg)] = value; |
121 | |
122 | ret = i2c_master_send(client, buf: write_buf, count: sizeof(write_buf)); |
123 | if (ret < 0) |
124 | return ret; |
125 | |
126 | return 0; |
127 | } |
128 | |
129 | static int seesaw_register_write_u32(struct i2c_client *client, u16 reg, |
130 | u32 value) |
131 | { |
132 | u8 write_buf[sizeof(reg) + sizeof(value)]; |
133 | int ret; |
134 | |
135 | put_unaligned_be16(val: reg, p: write_buf); |
136 | put_unaligned_be32(val: value, p: write_buf + sizeof(reg)); |
137 | ret = i2c_master_send(client, buf: write_buf, count: sizeof(write_buf)); |
138 | if (ret < 0) |
139 | return ret; |
140 | |
141 | return 0; |
142 | } |
143 | |
144 | static int seesaw_read_data(struct i2c_client *client, struct seesaw_data *data) |
145 | { |
146 | __be16 adc_data; |
147 | __be32 read_buf; |
148 | int err; |
149 | |
150 | err = seesaw_register_read(client, SEESAW_GPIO_BULK, |
151 | buf: &read_buf, count: sizeof(read_buf)); |
152 | if (err) |
153 | return err; |
154 | |
155 | data->button_state = ~be32_to_cpu(read_buf); |
156 | |
157 | err = seesaw_register_read(client, |
158 | SEESAW_ADC_BASE | |
159 | (SEESAW_ADC_OFFSET + SEESAW_ANALOG_X), |
160 | buf: &adc_data, count: sizeof(adc_data)); |
161 | if (err) |
162 | return err; |
163 | /* |
164 | * ADC reads left as max and right as 0, must be reversed since kernel |
165 | * expects reports in opposite order. |
166 | */ |
167 | data->x = SEESAW_JOYSTICK_MAX_AXIS - be16_to_cpu(adc_data); |
168 | |
169 | err = seesaw_register_read(client, |
170 | SEESAW_ADC_BASE | |
171 | (SEESAW_ADC_OFFSET + SEESAW_ANALOG_Y), |
172 | buf: &adc_data, count: sizeof(adc_data)); |
173 | if (err) |
174 | return err; |
175 | |
176 | data->y = be16_to_cpu(adc_data); |
177 | |
178 | return 0; |
179 | } |
180 | |
181 | static void seesaw_poll(struct input_dev *input) |
182 | { |
183 | struct seesaw_gamepad *private = input_get_drvdata(dev: input); |
184 | struct seesaw_data data; |
185 | int err, i; |
186 | |
187 | err = seesaw_read_data(client: private->i2c_client, data: &data); |
188 | if (err) { |
189 | dev_err_ratelimited(&input->dev, |
190 | "failed to read joystick state: %d\n" , err); |
191 | return; |
192 | } |
193 | |
194 | input_report_abs(dev: input, ABS_X, value: data.x); |
195 | input_report_abs(dev: input, ABS_Y, value: data.y); |
196 | |
197 | for_each_set_bit(i, &SEESAW_BUTTON_MASK, |
198 | BITS_PER_TYPE(SEESAW_BUTTON_MASK)) { |
199 | if (!sparse_keymap_report_event(dev: input, code: i, |
200 | value: data.button_state & BIT(i), |
201 | autorelease: false)) |
202 | dev_err_ratelimited(&input->dev, |
203 | "failed to report keymap event" ); |
204 | } |
205 | |
206 | input_sync(dev: input); |
207 | } |
208 | |
209 | static int seesaw_probe(struct i2c_client *client) |
210 | { |
211 | struct seesaw_gamepad *seesaw; |
212 | u8 hardware_id; |
213 | int err; |
214 | |
215 | err = seesaw_register_write_u8(client, SEESAW_STATUS_SWRST, value: 0xFF); |
216 | if (err) |
217 | return err; |
218 | |
219 | /* Wait for the registers to reset before proceeding */ |
220 | usleep_range(min: 10000, max: 15000); |
221 | |
222 | seesaw = devm_kzalloc(dev: &client->dev, size: sizeof(*seesaw), GFP_KERNEL); |
223 | if (!seesaw) |
224 | return -ENOMEM; |
225 | |
226 | err = seesaw_register_read(client, SEESAW_STATUS_HW_ID, |
227 | buf: &hardware_id, count: sizeof(hardware_id)); |
228 | if (err) |
229 | return err; |
230 | |
231 | dev_dbg(&client->dev, "Adafruit Seesaw Gamepad, Hardware ID: %02x\n" , |
232 | hardware_id); |
233 | |
234 | /* Set Pin Mode to input and enable pull-up resistors */ |
235 | err = seesaw_register_write_u32(client, SEESAW_GPIO_DIRCLR_BULK, |
236 | value: SEESAW_BUTTON_MASK); |
237 | if (err) |
238 | return err; |
239 | err = seesaw_register_write_u32(client, SEESAW_GPIO_PULLENSET, |
240 | value: SEESAW_BUTTON_MASK); |
241 | if (err) |
242 | return err; |
243 | err = seesaw_register_write_u32(client, SEESAW_GPIO_BULK_SET, |
244 | value: SEESAW_BUTTON_MASK); |
245 | if (err) |
246 | return err; |
247 | |
248 | seesaw->i2c_client = client; |
249 | seesaw->input_dev = devm_input_allocate_device(&client->dev); |
250 | if (!seesaw->input_dev) |
251 | return -ENOMEM; |
252 | |
253 | seesaw->input_dev->id.bustype = BUS_I2C; |
254 | seesaw->input_dev->name = "Adafruit Seesaw Gamepad" ; |
255 | seesaw->input_dev->phys = "i2c/" SEESAW_DEVICE_NAME; |
256 | input_set_drvdata(dev: seesaw->input_dev, data: seesaw); |
257 | input_set_abs_params(dev: seesaw->input_dev, ABS_X, |
258 | min: 0, SEESAW_JOYSTICK_MAX_AXIS, |
259 | SEESAW_JOYSTICK_FUZZ, SEESAW_JOYSTICK_FLAT); |
260 | input_set_abs_params(dev: seesaw->input_dev, ABS_Y, |
261 | min: 0, SEESAW_JOYSTICK_MAX_AXIS, |
262 | SEESAW_JOYSTICK_FUZZ, SEESAW_JOYSTICK_FLAT); |
263 | |
264 | err = sparse_keymap_setup(dev: seesaw->input_dev, keymap: seesaw_buttons_new, NULL); |
265 | if (err) { |
266 | dev_err(&client->dev, |
267 | "failed to set up input device keymap: %d\n" , err); |
268 | return err; |
269 | } |
270 | |
271 | err = input_setup_polling(dev: seesaw->input_dev, poll_fn: seesaw_poll); |
272 | if (err) { |
273 | dev_err(&client->dev, "failed to set up polling: %d\n" , err); |
274 | return err; |
275 | } |
276 | |
277 | input_set_poll_interval(dev: seesaw->input_dev, |
278 | SEESAW_GAMEPAD_POLL_INTERVAL_MS); |
279 | input_set_max_poll_interval(dev: seesaw->input_dev, SEESAW_GAMEPAD_POLL_MAX); |
280 | input_set_min_poll_interval(dev: seesaw->input_dev, SEESAW_GAMEPAD_POLL_MIN); |
281 | |
282 | err = input_register_device(seesaw->input_dev); |
283 | if (err) { |
284 | dev_err(&client->dev, "failed to register joystick: %d\n" , err); |
285 | return err; |
286 | } |
287 | |
288 | return 0; |
289 | } |
290 | |
291 | static const struct i2c_device_id seesaw_id_table[] = { |
292 | { SEESAW_DEVICE_NAME }, |
293 | { /* Sentinel */ } |
294 | }; |
295 | MODULE_DEVICE_TABLE(i2c, seesaw_id_table); |
296 | |
297 | static const struct of_device_id seesaw_of_table[] = { |
298 | { .compatible = "adafruit,seesaw-gamepad" }, |
299 | { /* Sentinel */ } |
300 | }; |
301 | MODULE_DEVICE_TABLE(of, seesaw_of_table); |
302 | |
303 | static struct i2c_driver seesaw_driver = { |
304 | .driver = { |
305 | .name = SEESAW_DEVICE_NAME, |
306 | .of_match_table = seesaw_of_table, |
307 | }, |
308 | .id_table = seesaw_id_table, |
309 | .probe = seesaw_probe, |
310 | }; |
311 | module_i2c_driver(seesaw_driver); |
312 | |
313 | MODULE_AUTHOR("Anshul Dalal <anshulusr@gmail.com>" ); |
314 | MODULE_DESCRIPTION("Adafruit Mini I2C Gamepad driver" ); |
315 | MODULE_LICENSE("GPL" ); |
316 | |