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 */
71 enum {
72 	EVENT_INIT,
73 	EVENT_MIDDLE,
74 	EVENT_RELEASE,
75 	EVENT_FIFO_END
76 };
77 
78 struct max11801_data {
79 	struct i2c_client		*client;
80 	struct input_dev		*input_dev;
81 };
82 
83 static 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 
89 static 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 
95 static 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 	}
149 out:
150 	return IRQ_HANDLED;
151 }
152 
153 static 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 
171 static 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 
215 static const struct i2c_device_id max11801_ts_id[] = {
216 	{"max11801", 0},
217 	{ }
218 };
219 MODULE_DEVICE_TABLE(i2c, max11801_ts_id);
220 
221 static const struct of_device_id max11801_ts_dt_ids[] = {
222 	{ .compatible = "maxim,max11801" },
223 	{ /* sentinel */ }
224 };
225 MODULE_DEVICE_TABLE(of, max11801_ts_dt_ids);
226 
227 static 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_new	= max11801_ts_probe,
234 };
235 
236 module_i2c_driver(max11801_ts_driver);
237 
238 MODULE_AUTHOR("Zhang Jiejing <jiejing.zhang@freescale.com>");
239 MODULE_DESCRIPTION("Touchscreen driver for MAXI MAX11801 controller");
240 MODULE_LICENSE("GPL");
241