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
read_register(struct i2c_client * client,int addr)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
max11801_write_reg(struct i2c_client * client,int addr,int data)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
max11801_ts_interrupt(int irq,void * dev_id)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
max11801_ts_phy_init(struct max11801_data * data)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
max11801_ts_probe(struct i2c_client * client)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 = 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