1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Driver for MAXI MAX11801 - A Resistive touch screen controller with
4 * i2c interface
5 *
6 * Copyright (C) 2011 Freescale Semiconductor, Inc.
7 * Author: Zhang Jiejing <jiejing.zhang@freescale.com>
8 *
9 * Based on mcs5000_ts.c
10 */
11
12/*
13 * This driver aims to support the series of MAXI touch chips max11801
14 * through max11803. The main difference between these 4 chips can be
15 * found in the table below:
16 * -----------------------------------------------------
17 * | CHIP     |  AUTO MODE SUPPORT(FIFO) | INTERFACE    |
18 * |----------------------------------------------------|
19 * | max11800 |  YES                     |   SPI        |
20 * | max11801 |  YES                     |   I2C        |
21 * | max11802 |  NO                      |   SPI        |
22 * | max11803 |  NO                      |   I2C        |
23 * ------------------------------------------------------
24 *
25 * Currently, this driver only supports max11801.
26 *
27 * Data Sheet:
28 * http://www.maxim-ic.com/datasheet/index.mvp/id/5943
29 */
30
31#include <linux/module.h>
32#include <linux/i2c.h>
33#include <linux/interrupt.h>
34#include <linux/input.h>
35#include <linux/slab.h>
36#include <linux/bitops.h>
37
38/* Register Address define */
39#define GENERNAL_STATUS_REG		0x00
40#define GENERNAL_CONF_REG		0x01
41#define MESURE_RES_CONF_REG		0x02
42#define MESURE_AVER_CONF_REG		0x03
43#define ADC_SAMPLE_TIME_CONF_REG	0x04
44#define PANEL_SETUPTIME_CONF_REG	0x05
45#define DELAY_CONVERSION_CONF_REG	0x06
46#define TOUCH_DETECT_PULLUP_CONF_REG	0x07
47#define AUTO_MODE_TIME_CONF_REG		0x08 /* only for max11800/max11801 */
48#define APERTURE_CONF_REG		0x09 /* only for max11800/max11801 */
49#define AUX_MESURE_CONF_REG		0x0a
50#define OP_MODE_CONF_REG		0x0b
51
52/* FIFO is found only in max11800 and max11801 */
53#define FIFO_RD_CMD			(0x50 << 1)
54#define MAX11801_FIFO_INT		(1 << 2)
55#define MAX11801_FIFO_OVERFLOW		(1 << 3)
56
57#define XY_BUFSIZE			4
58#define XY_BUF_OFFSET			4
59
60#define MAX11801_MAX_X			0xfff
61#define MAX11801_MAX_Y			0xfff
62
63#define MEASURE_TAG_OFFSET		2
64#define MEASURE_TAG_MASK		(3 << MEASURE_TAG_OFFSET)
65#define EVENT_TAG_OFFSET		0
66#define EVENT_TAG_MASK			(3 << EVENT_TAG_OFFSET)
67#define MEASURE_X_TAG			(0 << MEASURE_TAG_OFFSET)
68#define MEASURE_Y_TAG			(1 << MEASURE_TAG_OFFSET)
69
70/* These are the state of touch event state machine */
71enum {
72	EVENT_INIT,
73	EVENT_MIDDLE,
74	EVENT_RELEASE,
75	EVENT_FIFO_END
76};
77
78struct max11801_data {
79	struct i2c_client		*client;
80	struct input_dev		*input_dev;
81};
82
83static u8 read_register(struct i2c_client *client, int addr)
84{
85	/* XXX: The chip ignores LSB of register address */
86	return i2c_smbus_read_byte_data(client, addr << 1);
87}
88
89static int max11801_write_reg(struct i2c_client *client, int addr, int data)
90{
91	/* XXX: The chip ignores LSB of register address */
92	return i2c_smbus_write_byte_data(client, addr << 1, data);
93}
94
95static irqreturn_t max11801_ts_interrupt(int irq, void *dev_id)
96{
97	struct max11801_data *data = dev_id;
98	struct i2c_client *client = data->client;
99	int status, i, ret;
100	u8 buf[XY_BUFSIZE];
101	int x = -1;
102	int y = -1;
103
104	status = read_register(data->client, GENERNAL_STATUS_REG);
105
106	if (status & (MAX11801_FIFO_INT | MAX11801_FIFO_OVERFLOW)) {
107		status = read_register(data->client, GENERNAL_STATUS_REG);
108
109		ret = i2c_smbus_read_i2c_block_data(client, FIFO_RD_CMD,
110						    XY_BUFSIZE, buf);
111
112		/*
113		 * We should get 4 bytes buffer that contains X,Y
114		 * and event tag
115		 */
116		if (ret < XY_BUFSIZE)
117			goto out;
118
119		for (i = 0; i < XY_BUFSIZE; i += XY_BUFSIZE / 2) {
120			if ((buf[i + 1] & MEASURE_TAG_MASK) == MEASURE_X_TAG)
121				x = (buf[i] << XY_BUF_OFFSET) +
122				    (buf[i + 1] >> XY_BUF_OFFSET);
123			else if ((buf[i + 1] & MEASURE_TAG_MASK) == MEASURE_Y_TAG)
124				y = (buf[i] << XY_BUF_OFFSET) +
125				    (buf[i + 1] >> XY_BUF_OFFSET);
126		}
127
128		if ((buf[1] & EVENT_TAG_MASK) != (buf[3] & EVENT_TAG_MASK))
129			goto out;
130
131		switch (buf[1] & EVENT_TAG_MASK) {
132		case EVENT_INIT:
133		case EVENT_MIDDLE:
134			input_report_abs(data->input_dev, ABS_X, x);
135			input_report_abs(data->input_dev, ABS_Y, y);
136			input_event(data->input_dev, EV_KEY, BTN_TOUCH, 1);
137			input_sync(data->input_dev);
138			break;
139
140		case EVENT_RELEASE:
141			input_event(data->input_dev, EV_KEY, BTN_TOUCH, 0);
142			input_sync(data->input_dev);
143			break;
144
145		case EVENT_FIFO_END:
146			break;
147		}
148	}
149out:
150	return IRQ_HANDLED;
151}
152
153static void max11801_ts_phy_init(struct max11801_data *data)
154{
155	struct i2c_client *client = data->client;
156
157	/* Average X,Y, take 16 samples, average eight media sample */
158	max11801_write_reg(client, MESURE_AVER_CONF_REG, 0xff);
159	/* X,Y panel setup time set to 20us */
160	max11801_write_reg(client, PANEL_SETUPTIME_CONF_REG, 0x11);
161	/* Rough pullup time (2uS), Fine pullup time (10us)  */
162	max11801_write_reg(client, TOUCH_DETECT_PULLUP_CONF_REG, 0x10);
163	/* Auto mode init period = 5ms , scan period = 5ms*/
164	max11801_write_reg(client, AUTO_MODE_TIME_CONF_REG, 0xaa);
165	/* Aperture X,Y set to +- 4LSB */
166	max11801_write_reg(client, APERTURE_CONF_REG, 0x33);
167	/* Enable Power, enable Automode, enable Aperture, enable Average X,Y */
168	max11801_write_reg(client, OP_MODE_CONF_REG, 0x36);
169}
170
171static int max11801_ts_probe(struct i2c_client *client)
172{
173	struct max11801_data *data;
174	struct input_dev *input_dev;
175	int error;
176
177	data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
178	input_dev = devm_input_allocate_device(&client->dev);
179	if (!data || !input_dev) {
180		dev_err(&client->dev, "Failed to allocate memory\n");
181		return -ENOMEM;
182	}
183
184	data->client = client;
185	data->input_dev = input_dev;
186
187	input_dev->name = "max11801_ts";
188	input_dev->id.bustype = BUS_I2C;
189	input_dev->dev.parent = &client->dev;
190
191	__set_bit(EV_ABS, input_dev->evbit);
192	__set_bit(EV_KEY, input_dev->evbit);
193	__set_bit(BTN_TOUCH, input_dev->keybit);
194	input_set_abs_params(input_dev, ABS_X, 0, MAX11801_MAX_X, 0, 0);
195	input_set_abs_params(input_dev, ABS_Y, 0, MAX11801_MAX_Y, 0, 0);
196
197	max11801_ts_phy_init(data);
198
199	error = devm_request_threaded_irq(&client->dev, client->irq, NULL,
200					  max11801_ts_interrupt,
201					  IRQF_TRIGGER_LOW | IRQF_ONESHOT,
202					  "max11801_ts", data);
203	if (error) {
204		dev_err(&client->dev, "Failed to register interrupt\n");
205		return error;
206	}
207
208	error = input_register_device(data->input_dev);
209	if (error)
210		return error;
211
212	return 0;
213}
214
215static const struct i2c_device_id max11801_ts_id[] = {
216	{"max11801", 0},
217	{ }
218};
219MODULE_DEVICE_TABLE(i2c, max11801_ts_id);
220
221static const struct of_device_id max11801_ts_dt_ids[] = {
222	{ .compatible = "maxim,max11801" },
223	{ /* sentinel */ }
224};
225MODULE_DEVICE_TABLE(of, max11801_ts_dt_ids);
226
227static struct i2c_driver max11801_ts_driver = {
228	.driver = {
229		.name	= "max11801_ts",
230		.of_match_table = max11801_ts_dt_ids,
231	},
232	.id_table	= max11801_ts_id,
233	.probe		= max11801_ts_probe,
234};
235
236module_i2c_driver(max11801_ts_driver);
237
238MODULE_AUTHOR("Zhang Jiejing <jiejing.zhang@freescale.com>");
239MODULE_DESCRIPTION("Touchscreen driver for MAXI MAX11801 controller");
240MODULE_LICENSE("GPL");
241