19c92ab61SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only
2b06d43f7SDaniel Hung-yu Wu /*
3b06d43f7SDaniel Hung-yu Wu * Atmel Atmegaxx Capacitive Touch Button Driver
4b06d43f7SDaniel Hung-yu Wu *
5b06d43f7SDaniel Hung-yu Wu * Copyright (C) 2016 Google, inc.
6b06d43f7SDaniel Hung-yu Wu */
7b06d43f7SDaniel Hung-yu Wu
8b06d43f7SDaniel Hung-yu Wu /*
9b06d43f7SDaniel Hung-yu Wu * It's irrelevant that the HW used to develop captouch driver is based
10b06d43f7SDaniel Hung-yu Wu * on Atmega88PA part and uses QtouchADC parts for sensing touch.
11b06d43f7SDaniel Hung-yu Wu * Calling this driver "captouch" is an arbitrary way to distinguish
12b06d43f7SDaniel Hung-yu Wu * the protocol this driver supported by other atmel/qtouch drivers.
13b06d43f7SDaniel Hung-yu Wu *
14b06d43f7SDaniel Hung-yu Wu * Captouch driver supports a newer/different version of the I2C
15b06d43f7SDaniel Hung-yu Wu * registers/commands than the qt1070.c driver.
16b06d43f7SDaniel Hung-yu Wu * Don't let the similarity of the general driver structure fool you.
17b06d43f7SDaniel Hung-yu Wu *
18b06d43f7SDaniel Hung-yu Wu * For raw i2c access from userspace, use i2cset/i2cget
19b06d43f7SDaniel Hung-yu Wu * to poke at /dev/i2c-N devices.
20b06d43f7SDaniel Hung-yu Wu */
21b06d43f7SDaniel Hung-yu Wu
22b06d43f7SDaniel Hung-yu Wu #include <linux/device.h>
23b06d43f7SDaniel Hung-yu Wu #include <linux/kernel.h>
24b06d43f7SDaniel Hung-yu Wu #include <linux/module.h>
25b06d43f7SDaniel Hung-yu Wu #include <linux/init.h>
26b06d43f7SDaniel Hung-yu Wu #include <linux/i2c.h>
27b06d43f7SDaniel Hung-yu Wu #include <linux/input.h>
28b06d43f7SDaniel Hung-yu Wu #include <linux/interrupt.h>
29b06d43f7SDaniel Hung-yu Wu #include <linux/slab.h>
30b06d43f7SDaniel Hung-yu Wu
31b06d43f7SDaniel Hung-yu Wu /* Maximum number of buttons supported */
32b06d43f7SDaniel Hung-yu Wu #define MAX_NUM_OF_BUTTONS 8
33b06d43f7SDaniel Hung-yu Wu
34b06d43f7SDaniel Hung-yu Wu /* Registers */
35b06d43f7SDaniel Hung-yu Wu #define REG_KEY1_THRESHOLD 0x02
36b06d43f7SDaniel Hung-yu Wu #define REG_KEY2_THRESHOLD 0x03
37b06d43f7SDaniel Hung-yu Wu #define REG_KEY3_THRESHOLD 0x04
38b06d43f7SDaniel Hung-yu Wu #define REG_KEY4_THRESHOLD 0x05
39b06d43f7SDaniel Hung-yu Wu
40b06d43f7SDaniel Hung-yu Wu #define REG_KEY1_REF_H 0x20
41b06d43f7SDaniel Hung-yu Wu #define REG_KEY1_REF_L 0x21
42b06d43f7SDaniel Hung-yu Wu #define REG_KEY2_REF_H 0x22
43b06d43f7SDaniel Hung-yu Wu #define REG_KEY2_REF_L 0x23
44b06d43f7SDaniel Hung-yu Wu #define REG_KEY3_REF_H 0x24
45b06d43f7SDaniel Hung-yu Wu #define REG_KEY3_REF_L 0x25
46b06d43f7SDaniel Hung-yu Wu #define REG_KEY4_REF_H 0x26
47b06d43f7SDaniel Hung-yu Wu #define REG_KEY4_REF_L 0x27
48b06d43f7SDaniel Hung-yu Wu
49b06d43f7SDaniel Hung-yu Wu #define REG_KEY1_DLT_H 0x30
50b06d43f7SDaniel Hung-yu Wu #define REG_KEY1_DLT_L 0x31
51b06d43f7SDaniel Hung-yu Wu #define REG_KEY2_DLT_H 0x32
52b06d43f7SDaniel Hung-yu Wu #define REG_KEY2_DLT_L 0x33
53b06d43f7SDaniel Hung-yu Wu #define REG_KEY3_DLT_H 0x34
54b06d43f7SDaniel Hung-yu Wu #define REG_KEY3_DLT_L 0x35
55b06d43f7SDaniel Hung-yu Wu #define REG_KEY4_DLT_H 0x36
56b06d43f7SDaniel Hung-yu Wu #define REG_KEY4_DLT_L 0x37
57b06d43f7SDaniel Hung-yu Wu
58b06d43f7SDaniel Hung-yu Wu #define REG_KEY_STATE 0x3C
59b06d43f7SDaniel Hung-yu Wu
60b06d43f7SDaniel Hung-yu Wu /*
61b06d43f7SDaniel Hung-yu Wu * @i2c_client: I2C slave device client pointer
62b06d43f7SDaniel Hung-yu Wu * @input: Input device pointer
63b06d43f7SDaniel Hung-yu Wu * @num_btn: Number of buttons
64b06d43f7SDaniel Hung-yu Wu * @keycodes: map of button# to KeyCode
65b06d43f7SDaniel Hung-yu Wu * @prev_btn: Previous key state to detect button "press" or "release"
66b06d43f7SDaniel Hung-yu Wu * @xfer_buf: I2C transfer buffer
67b06d43f7SDaniel Hung-yu Wu */
68b06d43f7SDaniel Hung-yu Wu struct atmel_captouch_device {
69b06d43f7SDaniel Hung-yu Wu struct i2c_client *client;
70b06d43f7SDaniel Hung-yu Wu struct input_dev *input;
71b06d43f7SDaniel Hung-yu Wu u32 num_btn;
72b06d43f7SDaniel Hung-yu Wu u32 keycodes[MAX_NUM_OF_BUTTONS];
73b06d43f7SDaniel Hung-yu Wu u8 prev_btn;
74b06d43f7SDaniel Hung-yu Wu u8 xfer_buf[8] ____cacheline_aligned;
75b06d43f7SDaniel Hung-yu Wu };
76b06d43f7SDaniel Hung-yu Wu
77b06d43f7SDaniel Hung-yu Wu /*
78b06d43f7SDaniel Hung-yu Wu * Read from I2C slave device
79b06d43f7SDaniel Hung-yu Wu * The protocol is that the client has to provide both the register address
80b06d43f7SDaniel Hung-yu Wu * and the length, and while reading back the device would prepend the data
81b06d43f7SDaniel Hung-yu Wu * with address and length for verification.
82b06d43f7SDaniel Hung-yu Wu */
atmel_read(struct atmel_captouch_device * capdev,u8 reg,u8 * data,size_t len)83b06d43f7SDaniel Hung-yu Wu static int atmel_read(struct atmel_captouch_device *capdev,
84b06d43f7SDaniel Hung-yu Wu u8 reg, u8 *data, size_t len)
85b06d43f7SDaniel Hung-yu Wu {
86b06d43f7SDaniel Hung-yu Wu struct i2c_client *client = capdev->client;
87b06d43f7SDaniel Hung-yu Wu struct device *dev = &client->dev;
88b06d43f7SDaniel Hung-yu Wu struct i2c_msg msg[2];
89b06d43f7SDaniel Hung-yu Wu int err;
90b06d43f7SDaniel Hung-yu Wu
91b06d43f7SDaniel Hung-yu Wu if (len > sizeof(capdev->xfer_buf) - 2)
92b06d43f7SDaniel Hung-yu Wu return -EINVAL;
93b06d43f7SDaniel Hung-yu Wu
94b06d43f7SDaniel Hung-yu Wu capdev->xfer_buf[0] = reg;
95b06d43f7SDaniel Hung-yu Wu capdev->xfer_buf[1] = len;
96b06d43f7SDaniel Hung-yu Wu
97b06d43f7SDaniel Hung-yu Wu msg[0].addr = client->addr;
98b06d43f7SDaniel Hung-yu Wu msg[0].flags = 0;
99b06d43f7SDaniel Hung-yu Wu msg[0].buf = capdev->xfer_buf;
100b06d43f7SDaniel Hung-yu Wu msg[0].len = 2;
101b06d43f7SDaniel Hung-yu Wu
102b06d43f7SDaniel Hung-yu Wu msg[1].addr = client->addr;
103b06d43f7SDaniel Hung-yu Wu msg[1].flags = I2C_M_RD;
104b06d43f7SDaniel Hung-yu Wu msg[1].buf = capdev->xfer_buf;
105b06d43f7SDaniel Hung-yu Wu msg[1].len = len + 2;
106b06d43f7SDaniel Hung-yu Wu
107b06d43f7SDaniel Hung-yu Wu err = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
108b06d43f7SDaniel Hung-yu Wu if (err != ARRAY_SIZE(msg))
109b06d43f7SDaniel Hung-yu Wu return err < 0 ? err : -EIO;
110b06d43f7SDaniel Hung-yu Wu
111b06d43f7SDaniel Hung-yu Wu if (capdev->xfer_buf[0] != reg) {
112b06d43f7SDaniel Hung-yu Wu dev_err(dev,
113b06d43f7SDaniel Hung-yu Wu "I2C read error: register address does not match (%#02x vs %02x)\n",
114b06d43f7SDaniel Hung-yu Wu capdev->xfer_buf[0], reg);
115b06d43f7SDaniel Hung-yu Wu return -ECOMM;
116b06d43f7SDaniel Hung-yu Wu }
117b06d43f7SDaniel Hung-yu Wu
118b06d43f7SDaniel Hung-yu Wu memcpy(data, &capdev->xfer_buf[2], len);
119b06d43f7SDaniel Hung-yu Wu
120b06d43f7SDaniel Hung-yu Wu return 0;
121b06d43f7SDaniel Hung-yu Wu }
122b06d43f7SDaniel Hung-yu Wu
123b06d43f7SDaniel Hung-yu Wu /*
124b06d43f7SDaniel Hung-yu Wu * Handle interrupt and report the key changes to the input system.
125b06d43f7SDaniel Hung-yu Wu * Multi-touch can be supported; however, it really depends on whether
126b06d43f7SDaniel Hung-yu Wu * the device can multi-touch.
127b06d43f7SDaniel Hung-yu Wu */
atmel_captouch_isr(int irq,void * data)128b06d43f7SDaniel Hung-yu Wu static irqreturn_t atmel_captouch_isr(int irq, void *data)
129b06d43f7SDaniel Hung-yu Wu {
130b06d43f7SDaniel Hung-yu Wu struct atmel_captouch_device *capdev = data;
131b06d43f7SDaniel Hung-yu Wu struct device *dev = &capdev->client->dev;
132b06d43f7SDaniel Hung-yu Wu int error;
133b06d43f7SDaniel Hung-yu Wu int i;
134b06d43f7SDaniel Hung-yu Wu u8 new_btn;
135b06d43f7SDaniel Hung-yu Wu u8 changed_btn;
136b06d43f7SDaniel Hung-yu Wu
137b06d43f7SDaniel Hung-yu Wu error = atmel_read(capdev, REG_KEY_STATE, &new_btn, 1);
138b06d43f7SDaniel Hung-yu Wu if (error) {
139b06d43f7SDaniel Hung-yu Wu dev_err(dev, "failed to read button state: %d\n", error);
140b06d43f7SDaniel Hung-yu Wu goto out;
141b06d43f7SDaniel Hung-yu Wu }
142b06d43f7SDaniel Hung-yu Wu
143b06d43f7SDaniel Hung-yu Wu dev_dbg(dev, "%s: button state %#02x\n", __func__, new_btn);
144b06d43f7SDaniel Hung-yu Wu
145b06d43f7SDaniel Hung-yu Wu changed_btn = new_btn ^ capdev->prev_btn;
146b06d43f7SDaniel Hung-yu Wu capdev->prev_btn = new_btn;
147b06d43f7SDaniel Hung-yu Wu
148b06d43f7SDaniel Hung-yu Wu for (i = 0; i < capdev->num_btn; i++) {
149b06d43f7SDaniel Hung-yu Wu if (changed_btn & BIT(i))
150b06d43f7SDaniel Hung-yu Wu input_report_key(capdev->input,
151b06d43f7SDaniel Hung-yu Wu capdev->keycodes[i],
152b06d43f7SDaniel Hung-yu Wu new_btn & BIT(i));
153b06d43f7SDaniel Hung-yu Wu }
154b06d43f7SDaniel Hung-yu Wu
155b06d43f7SDaniel Hung-yu Wu input_sync(capdev->input);
156b06d43f7SDaniel Hung-yu Wu
157b06d43f7SDaniel Hung-yu Wu out:
158b06d43f7SDaniel Hung-yu Wu return IRQ_HANDLED;
159b06d43f7SDaniel Hung-yu Wu }
160b06d43f7SDaniel Hung-yu Wu
161b06d43f7SDaniel Hung-yu Wu /*
162b06d43f7SDaniel Hung-yu Wu * Probe function to setup the device, input system and interrupt
163b06d43f7SDaniel Hung-yu Wu */
atmel_captouch_probe(struct i2c_client * client)16422972ef8SUwe Kleine-König static int atmel_captouch_probe(struct i2c_client *client)
165b06d43f7SDaniel Hung-yu Wu {
166b06d43f7SDaniel Hung-yu Wu struct atmel_captouch_device *capdev;
167b06d43f7SDaniel Hung-yu Wu struct device *dev = &client->dev;
168b06d43f7SDaniel Hung-yu Wu struct device_node *node;
169b06d43f7SDaniel Hung-yu Wu int i;
170b06d43f7SDaniel Hung-yu Wu int err;
171b06d43f7SDaniel Hung-yu Wu
172b06d43f7SDaniel Hung-yu Wu if (!i2c_check_functionality(client->adapter,
173b06d43f7SDaniel Hung-yu Wu I2C_FUNC_SMBUS_BYTE_DATA |
174b06d43f7SDaniel Hung-yu Wu I2C_FUNC_SMBUS_WORD_DATA |
175b06d43f7SDaniel Hung-yu Wu I2C_FUNC_SMBUS_I2C_BLOCK)) {
176b06d43f7SDaniel Hung-yu Wu dev_err(dev, "needed i2c functionality is not supported\n");
177b06d43f7SDaniel Hung-yu Wu return -EINVAL;
178b06d43f7SDaniel Hung-yu Wu }
179b06d43f7SDaniel Hung-yu Wu
180b06d43f7SDaniel Hung-yu Wu capdev = devm_kzalloc(dev, sizeof(*capdev), GFP_KERNEL);
181b06d43f7SDaniel Hung-yu Wu if (!capdev)
182b06d43f7SDaniel Hung-yu Wu return -ENOMEM;
183b06d43f7SDaniel Hung-yu Wu
184b06d43f7SDaniel Hung-yu Wu capdev->client = client;
185b06d43f7SDaniel Hung-yu Wu
186b06d43f7SDaniel Hung-yu Wu err = atmel_read(capdev, REG_KEY_STATE,
187b06d43f7SDaniel Hung-yu Wu &capdev->prev_btn, sizeof(capdev->prev_btn));
188b06d43f7SDaniel Hung-yu Wu if (err) {
189b06d43f7SDaniel Hung-yu Wu dev_err(dev, "failed to read initial button state: %d\n", err);
190b06d43f7SDaniel Hung-yu Wu return err;
191b06d43f7SDaniel Hung-yu Wu }
192b06d43f7SDaniel Hung-yu Wu
193b06d43f7SDaniel Hung-yu Wu capdev->input = devm_input_allocate_device(dev);
194b06d43f7SDaniel Hung-yu Wu if (!capdev->input) {
195b06d43f7SDaniel Hung-yu Wu dev_err(dev, "failed to allocate input device\n");
196b06d43f7SDaniel Hung-yu Wu return -ENOMEM;
197b06d43f7SDaniel Hung-yu Wu }
198b06d43f7SDaniel Hung-yu Wu
199b06d43f7SDaniel Hung-yu Wu capdev->input->id.bustype = BUS_I2C;
200b06d43f7SDaniel Hung-yu Wu capdev->input->id.product = 0x880A;
201b06d43f7SDaniel Hung-yu Wu capdev->input->id.version = 0;
202b06d43f7SDaniel Hung-yu Wu capdev->input->name = "ATMegaXX Capacitive Button Controller";
203b06d43f7SDaniel Hung-yu Wu __set_bit(EV_KEY, capdev->input->evbit);
204b06d43f7SDaniel Hung-yu Wu
205b06d43f7SDaniel Hung-yu Wu node = dev->of_node;
206b06d43f7SDaniel Hung-yu Wu if (!node) {
207b06d43f7SDaniel Hung-yu Wu dev_err(dev, "failed to find matching node in device tree\n");
208b06d43f7SDaniel Hung-yu Wu return -EINVAL;
209b06d43f7SDaniel Hung-yu Wu }
210b06d43f7SDaniel Hung-yu Wu
211b06d43f7SDaniel Hung-yu Wu if (of_property_read_bool(node, "autorepeat"))
212b06d43f7SDaniel Hung-yu Wu __set_bit(EV_REP, capdev->input->evbit);
213b06d43f7SDaniel Hung-yu Wu
214b06d43f7SDaniel Hung-yu Wu capdev->num_btn = of_property_count_u32_elems(node, "linux,keymap");
215b06d43f7SDaniel Hung-yu Wu if (capdev->num_btn > MAX_NUM_OF_BUTTONS)
216b06d43f7SDaniel Hung-yu Wu capdev->num_btn = MAX_NUM_OF_BUTTONS;
217b06d43f7SDaniel Hung-yu Wu
218b06d43f7SDaniel Hung-yu Wu err = of_property_read_u32_array(node, "linux,keycodes",
219b06d43f7SDaniel Hung-yu Wu capdev->keycodes,
220b06d43f7SDaniel Hung-yu Wu capdev->num_btn);
221b06d43f7SDaniel Hung-yu Wu if (err) {
222b06d43f7SDaniel Hung-yu Wu dev_err(dev,
223b06d43f7SDaniel Hung-yu Wu "failed to read linux,keycode property: %d\n", err);
224b06d43f7SDaniel Hung-yu Wu return err;
225b06d43f7SDaniel Hung-yu Wu }
226b06d43f7SDaniel Hung-yu Wu
227b06d43f7SDaniel Hung-yu Wu for (i = 0; i < capdev->num_btn; i++)
228b06d43f7SDaniel Hung-yu Wu __set_bit(capdev->keycodes[i], capdev->input->keybit);
229b06d43f7SDaniel Hung-yu Wu
230b06d43f7SDaniel Hung-yu Wu capdev->input->keycode = capdev->keycodes;
231b06d43f7SDaniel Hung-yu Wu capdev->input->keycodesize = sizeof(capdev->keycodes[0]);
232b06d43f7SDaniel Hung-yu Wu capdev->input->keycodemax = capdev->num_btn;
233b06d43f7SDaniel Hung-yu Wu
234b06d43f7SDaniel Hung-yu Wu err = input_register_device(capdev->input);
235b06d43f7SDaniel Hung-yu Wu if (err)
236b06d43f7SDaniel Hung-yu Wu return err;
237b06d43f7SDaniel Hung-yu Wu
238b06d43f7SDaniel Hung-yu Wu err = devm_request_threaded_irq(dev, client->irq,
239b06d43f7SDaniel Hung-yu Wu NULL, atmel_captouch_isr,
240b06d43f7SDaniel Hung-yu Wu IRQF_ONESHOT,
241b06d43f7SDaniel Hung-yu Wu "atmel_captouch", capdev);
242b06d43f7SDaniel Hung-yu Wu if (err) {
243b06d43f7SDaniel Hung-yu Wu dev_err(dev, "failed to request irq %d: %d\n",
244b06d43f7SDaniel Hung-yu Wu client->irq, err);
245b06d43f7SDaniel Hung-yu Wu return err;
246b06d43f7SDaniel Hung-yu Wu }
247b06d43f7SDaniel Hung-yu Wu
248b06d43f7SDaniel Hung-yu Wu return 0;
249b06d43f7SDaniel Hung-yu Wu }
250b06d43f7SDaniel Hung-yu Wu
251b06d43f7SDaniel Hung-yu Wu static const struct of_device_id atmel_captouch_of_id[] = {
252b06d43f7SDaniel Hung-yu Wu {
253b06d43f7SDaniel Hung-yu Wu .compatible = "atmel,captouch",
254b06d43f7SDaniel Hung-yu Wu },
255b06d43f7SDaniel Hung-yu Wu { /* sentinel */ }
256b06d43f7SDaniel Hung-yu Wu };
257b06d43f7SDaniel Hung-yu Wu MODULE_DEVICE_TABLE(of, atmel_captouch_of_id);
258b06d43f7SDaniel Hung-yu Wu
259b06d43f7SDaniel Hung-yu Wu static const struct i2c_device_id atmel_captouch_id[] = {
260b06d43f7SDaniel Hung-yu Wu { "atmel_captouch", 0 },
261b06d43f7SDaniel Hung-yu Wu { }
262b06d43f7SDaniel Hung-yu Wu };
263b06d43f7SDaniel Hung-yu Wu MODULE_DEVICE_TABLE(i2c, atmel_captouch_id);
264b06d43f7SDaniel Hung-yu Wu
265b06d43f7SDaniel Hung-yu Wu static struct i2c_driver atmel_captouch_driver = {
266*d8bde56dSUwe Kleine-König .probe = atmel_captouch_probe,
267b06d43f7SDaniel Hung-yu Wu .id_table = atmel_captouch_id,
268b06d43f7SDaniel Hung-yu Wu .driver = {
269b06d43f7SDaniel Hung-yu Wu .name = "atmel_captouch",
27048a4dec8SJean Delvare .of_match_table = atmel_captouch_of_id,
271b06d43f7SDaniel Hung-yu Wu },
272b06d43f7SDaniel Hung-yu Wu };
273b06d43f7SDaniel Hung-yu Wu module_i2c_driver(atmel_captouch_driver);
274b06d43f7SDaniel Hung-yu Wu
275b06d43f7SDaniel Hung-yu Wu /* Module information */
276b06d43f7SDaniel Hung-yu Wu MODULE_AUTHOR("Hung-yu Wu <hywu@google.com>");
277b06d43f7SDaniel Hung-yu Wu MODULE_DESCRIPTION("Atmel ATmegaXX Capacitance Touch Sensor I2C Driver");
278b06d43f7SDaniel Hung-yu Wu MODULE_LICENSE("GPL v2");
279