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 /* fall through */ 134 case EVENT_MIDDLE: 135 input_report_abs(data->input_dev, ABS_X, x); 136 input_report_abs(data->input_dev, ABS_Y, y); 137 input_event(data->input_dev, EV_KEY, BTN_TOUCH, 1); 138 input_sync(data->input_dev); 139 break; 140 141 case EVENT_RELEASE: 142 input_event(data->input_dev, EV_KEY, BTN_TOUCH, 0); 143 input_sync(data->input_dev); 144 break; 145 146 case EVENT_FIFO_END: 147 break; 148 } 149 } 150 out: 151 return IRQ_HANDLED; 152 } 153 154 static void max11801_ts_phy_init(struct max11801_data *data) 155 { 156 struct i2c_client *client = data->client; 157 158 /* Average X,Y, take 16 samples, average eight media sample */ 159 max11801_write_reg(client, MESURE_AVER_CONF_REG, 0xff); 160 /* X,Y panel setup time set to 20us */ 161 max11801_write_reg(client, PANEL_SETUPTIME_CONF_REG, 0x11); 162 /* Rough pullup time (2uS), Fine pullup time (10us) */ 163 max11801_write_reg(client, TOUCH_DETECT_PULLUP_CONF_REG, 0x10); 164 /* Auto mode init period = 5ms , scan period = 5ms*/ 165 max11801_write_reg(client, AUTO_MODE_TIME_CONF_REG, 0xaa); 166 /* Aperture X,Y set to +- 4LSB */ 167 max11801_write_reg(client, APERTURE_CONF_REG, 0x33); 168 /* Enable Power, enable Automode, enable Aperture, enable Average X,Y */ 169 max11801_write_reg(client, OP_MODE_CONF_REG, 0x36); 170 } 171 172 static int max11801_ts_probe(struct i2c_client *client, 173 const struct i2c_device_id *id) 174 { 175 struct max11801_data *data; 176 struct input_dev *input_dev; 177 int error; 178 179 data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL); 180 input_dev = devm_input_allocate_device(&client->dev); 181 if (!data || !input_dev) { 182 dev_err(&client->dev, "Failed to allocate memory\n"); 183 return -ENOMEM; 184 } 185 186 data->client = client; 187 data->input_dev = input_dev; 188 189 input_dev->name = "max11801_ts"; 190 input_dev->id.bustype = BUS_I2C; 191 input_dev->dev.parent = &client->dev; 192 193 __set_bit(EV_ABS, input_dev->evbit); 194 __set_bit(EV_KEY, input_dev->evbit); 195 __set_bit(BTN_TOUCH, input_dev->keybit); 196 input_set_abs_params(input_dev, ABS_X, 0, MAX11801_MAX_X, 0, 0); 197 input_set_abs_params(input_dev, ABS_Y, 0, MAX11801_MAX_Y, 0, 0); 198 199 max11801_ts_phy_init(data); 200 201 error = devm_request_threaded_irq(&client->dev, client->irq, NULL, 202 max11801_ts_interrupt, 203 IRQF_TRIGGER_LOW | IRQF_ONESHOT, 204 "max11801_ts", data); 205 if (error) { 206 dev_err(&client->dev, "Failed to register interrupt\n"); 207 return error; 208 } 209 210 error = input_register_device(data->input_dev); 211 if (error) 212 return error; 213 214 return 0; 215 } 216 217 static const struct i2c_device_id max11801_ts_id[] = { 218 {"max11801", 0}, 219 { } 220 }; 221 MODULE_DEVICE_TABLE(i2c, max11801_ts_id); 222 223 static const struct of_device_id max11801_ts_dt_ids[] = { 224 { .compatible = "maxim,max11801" }, 225 { /* sentinel */ } 226 }; 227 MODULE_DEVICE_TABLE(of, max11801_ts_dt_ids); 228 229 static struct i2c_driver max11801_ts_driver = { 230 .driver = { 231 .name = "max11801_ts", 232 .of_match_table = max11801_ts_dt_ids, 233 }, 234 .id_table = max11801_ts_id, 235 .probe = max11801_ts_probe, 236 }; 237 238 module_i2c_driver(max11801_ts_driver); 239 240 MODULE_AUTHOR("Zhang Jiejing <jiejing.zhang@freescale.com>"); 241 MODULE_DESCRIPTION("Touchscreen driver for MAXI MAX11801 controller"); 242 MODULE_LICENSE("GPL"); 243