Loading...
Note: File does not exist in v3.15.
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
59static 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
64struct seesaw_gamepad {
65 struct input_dev *input_dev;
66 struct i2c_client *i2c_client;
67};
68
69struct seesaw_data {
70 u16 x;
71 u16 y;
72 u32 button_state;
73};
74
75static 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
85static 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(client->adapter, message_buf,
106 ARRAY_SIZE(message_buf));
107 if (ret < 0)
108 return ret;
109
110 return 0;
111}
112
113static 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(reg, write_buf);
120 write_buf[sizeof(reg)] = value;
121
122 ret = i2c_master_send(client, write_buf, sizeof(write_buf));
123 if (ret < 0)
124 return ret;
125
126 return 0;
127}
128
129static 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(reg, write_buf);
136 put_unaligned_be32(value, write_buf + sizeof(reg));
137 ret = i2c_master_send(client, write_buf, sizeof(write_buf));
138 if (ret < 0)
139 return ret;
140
141 return 0;
142}
143
144static 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 &read_buf, 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 &adc_data, 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 &adc_data, sizeof(adc_data));
173 if (err)
174 return err;
175
176 data->y = be16_to_cpu(adc_data);
177
178 return 0;
179}
180
181static void seesaw_poll(struct input_dev *input)
182{
183 struct seesaw_gamepad *private = input_get_drvdata(input);
184 struct seesaw_data data;
185 int err, i;
186
187 err = seesaw_read_data(private->i2c_client, &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(input, ABS_X, data.x);
195 input_report_abs(input, ABS_Y, 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(input, i,
200 data.button_state & BIT(i),
201 false))
202 dev_err_ratelimited(&input->dev,
203 "failed to report keymap event");
204 }
205
206 input_sync(input);
207}
208
209static 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, 0xFF);
216 if (err)
217 return err;
218
219 /* Wait for the registers to reset before proceeding */
220 usleep_range(10000, 15000);
221
222 seesaw = devm_kzalloc(&client->dev, sizeof(*seesaw), GFP_KERNEL);
223 if (!seesaw)
224 return -ENOMEM;
225
226 err = seesaw_register_read(client, SEESAW_STATUS_HW_ID,
227 &hardware_id, 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 SEESAW_BUTTON_MASK);
237 if (err)
238 return err;
239 err = seesaw_register_write_u32(client, SEESAW_GPIO_PULLENSET,
240 SEESAW_BUTTON_MASK);
241 if (err)
242 return err;
243 err = seesaw_register_write_u32(client, SEESAW_GPIO_BULK_SET,
244 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(seesaw->input_dev, seesaw);
257 input_set_abs_params(seesaw->input_dev, ABS_X,
258 0, SEESAW_JOYSTICK_MAX_AXIS,
259 SEESAW_JOYSTICK_FUZZ, SEESAW_JOYSTICK_FLAT);
260 input_set_abs_params(seesaw->input_dev, ABS_Y,
261 0, SEESAW_JOYSTICK_MAX_AXIS,
262 SEESAW_JOYSTICK_FUZZ, SEESAW_JOYSTICK_FLAT);
263
264 err = sparse_keymap_setup(seesaw->input_dev, 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(seesaw->input_dev, 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(seesaw->input_dev,
278 SEESAW_GAMEPAD_POLL_INTERVAL_MS);
279 input_set_max_poll_interval(seesaw->input_dev, SEESAW_GAMEPAD_POLL_MAX);
280 input_set_min_poll_interval(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
291static const struct i2c_device_id seesaw_id_table[] = {
292 { SEESAW_DEVICE_NAME },
293 { /* Sentinel */ }
294};
295MODULE_DEVICE_TABLE(i2c, seesaw_id_table);
296
297static const struct of_device_id seesaw_of_table[] = {
298 { .compatible = "adafruit,seesaw-gamepad"},
299 { /* Sentinel */ }
300};
301MODULE_DEVICE_TABLE(of, seesaw_of_table);
302
303static 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};
311module_i2c_driver(seesaw_driver);
312
313MODULE_AUTHOR("Anshul Dalal <anshulusr@gmail.com>");
314MODULE_DESCRIPTION("Adafruit Mini I2C Gamepad driver");
315MODULE_LICENSE("GPL");