1 /* 2 * Driver for ChipOne icn8318 i2c touchscreen controller 3 * 4 * Copyright (c) 2015 Red Hat Inc. 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License, or 9 * (at your option) any later version. 10 * 11 * Red Hat authors: 12 * Hans de Goede <hdegoede@redhat.com> 13 */ 14 15 #include <linux/gpio/consumer.h> 16 #include <linux/interrupt.h> 17 #include <linux/i2c.h> 18 #include <linux/input.h> 19 #include <linux/input/mt.h> 20 #include <linux/input/touchscreen.h> 21 #include <linux/module.h> 22 #include <linux/of.h> 23 24 #define ICN8318_REG_POWER 4 25 #define ICN8318_REG_TOUCHDATA 16 26 27 #define ICN8318_POWER_ACTIVE 0 28 #define ICN8318_POWER_MONITOR 1 29 #define ICN8318_POWER_HIBERNATE 2 30 31 #define ICN8318_MAX_TOUCHES 5 32 33 struct icn8318_touch { 34 __u8 slot; 35 __be16 x; 36 __be16 y; 37 __u8 pressure; /* Seems more like finger width then pressure really */ 38 __u8 event; 39 /* The difference between 2 and 3 is unclear */ 40 #define ICN8318_EVENT_NO_DATA 1 /* No finger seen yet since wakeup */ 41 #define ICN8318_EVENT_UPDATE1 2 /* New or updated coordinates */ 42 #define ICN8318_EVENT_UPDATE2 3 /* New or updated coordinates */ 43 #define ICN8318_EVENT_END 4 /* Finger lifted */ 44 } __packed; 45 46 struct icn8318_touch_data { 47 __u8 softbutton; 48 __u8 touch_count; 49 struct icn8318_touch touches[ICN8318_MAX_TOUCHES]; 50 } __packed; 51 52 struct icn8318_data { 53 struct i2c_client *client; 54 struct input_dev *input; 55 struct gpio_desc *wake_gpio; 56 struct touchscreen_properties prop; 57 }; 58 59 static int icn8318_read_touch_data(struct i2c_client *client, 60 struct icn8318_touch_data *touch_data) 61 { 62 u8 reg = ICN8318_REG_TOUCHDATA; 63 struct i2c_msg msg[2] = { 64 { 65 .addr = client->addr, 66 .len = 1, 67 .buf = ® 68 }, 69 { 70 .addr = client->addr, 71 .flags = I2C_M_RD, 72 .len = sizeof(struct icn8318_touch_data), 73 .buf = (u8 *)touch_data 74 } 75 }; 76 77 return i2c_transfer(client->adapter, msg, 2); 78 } 79 80 static inline bool icn8318_touch_active(u8 event) 81 { 82 return (event == ICN8318_EVENT_UPDATE1) || 83 (event == ICN8318_EVENT_UPDATE2); 84 } 85 86 static irqreturn_t icn8318_irq(int irq, void *dev_id) 87 { 88 struct icn8318_data *data = dev_id; 89 struct device *dev = &data->client->dev; 90 struct icn8318_touch_data touch_data; 91 int i, ret; 92 93 ret = icn8318_read_touch_data(data->client, &touch_data); 94 if (ret < 0) { 95 dev_err(dev, "Error reading touch data: %d\n", ret); 96 return IRQ_HANDLED; 97 } 98 99 if (touch_data.softbutton) { 100 /* 101 * Other data is invalid when a softbutton is pressed. 102 * This needs some extra devicetree bindings to map the icn8318 103 * softbutton codes to evdev codes. Currently no known devices 104 * use this. 105 */ 106 return IRQ_HANDLED; 107 } 108 109 if (touch_data.touch_count > ICN8318_MAX_TOUCHES) { 110 dev_warn(dev, "Too much touches %d > %d\n", 111 touch_data.touch_count, ICN8318_MAX_TOUCHES); 112 touch_data.touch_count = ICN8318_MAX_TOUCHES; 113 } 114 115 for (i = 0; i < touch_data.touch_count; i++) { 116 struct icn8318_touch *touch = &touch_data.touches[i]; 117 bool act = icn8318_touch_active(touch->event); 118 119 input_mt_slot(data->input, touch->slot); 120 input_mt_report_slot_state(data->input, MT_TOOL_FINGER, act); 121 if (!act) 122 continue; 123 124 touchscreen_report_pos(data->input, &data->prop, 125 be16_to_cpu(touch->x), 126 be16_to_cpu(touch->y), true); 127 } 128 129 input_mt_sync_frame(data->input); 130 input_sync(data->input); 131 132 return IRQ_HANDLED; 133 } 134 135 static int icn8318_start(struct input_dev *dev) 136 { 137 struct icn8318_data *data = input_get_drvdata(dev); 138 139 enable_irq(data->client->irq); 140 gpiod_set_value_cansleep(data->wake_gpio, 1); 141 142 return 0; 143 } 144 145 static void icn8318_stop(struct input_dev *dev) 146 { 147 struct icn8318_data *data = input_get_drvdata(dev); 148 149 disable_irq(data->client->irq); 150 i2c_smbus_write_byte_data(data->client, ICN8318_REG_POWER, 151 ICN8318_POWER_HIBERNATE); 152 gpiod_set_value_cansleep(data->wake_gpio, 0); 153 } 154 155 #ifdef CONFIG_PM_SLEEP 156 static int icn8318_suspend(struct device *dev) 157 { 158 struct icn8318_data *data = i2c_get_clientdata(to_i2c_client(dev)); 159 160 mutex_lock(&data->input->mutex); 161 if (data->input->users) 162 icn8318_stop(data->input); 163 mutex_unlock(&data->input->mutex); 164 165 return 0; 166 } 167 168 static int icn8318_resume(struct device *dev) 169 { 170 struct icn8318_data *data = i2c_get_clientdata(to_i2c_client(dev)); 171 172 mutex_lock(&data->input->mutex); 173 if (data->input->users) 174 icn8318_start(data->input); 175 mutex_unlock(&data->input->mutex); 176 177 return 0; 178 } 179 #endif 180 181 static SIMPLE_DEV_PM_OPS(icn8318_pm_ops, icn8318_suspend, icn8318_resume); 182 183 static int icn8318_probe(struct i2c_client *client, 184 const struct i2c_device_id *id) 185 { 186 struct device *dev = &client->dev; 187 struct icn8318_data *data; 188 struct input_dev *input; 189 int error; 190 191 if (!client->irq) { 192 dev_err(dev, "Error no irq specified\n"); 193 return -EINVAL; 194 } 195 196 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); 197 if (!data) 198 return -ENOMEM; 199 200 data->wake_gpio = devm_gpiod_get(dev, "wake", GPIOD_OUT_LOW); 201 if (IS_ERR(data->wake_gpio)) { 202 error = PTR_ERR(data->wake_gpio); 203 if (error != -EPROBE_DEFER) 204 dev_err(dev, "Error getting wake gpio: %d\n", error); 205 return error; 206 } 207 208 input = devm_input_allocate_device(dev); 209 if (!input) 210 return -ENOMEM; 211 212 input->name = client->name; 213 input->id.bustype = BUS_I2C; 214 input->open = icn8318_start; 215 input->close = icn8318_stop; 216 input->dev.parent = dev; 217 218 input_set_capability(input, EV_ABS, ABS_MT_POSITION_X); 219 input_set_capability(input, EV_ABS, ABS_MT_POSITION_Y); 220 221 touchscreen_parse_properties(input, true, &data->prop); 222 if (!input_abs_get_max(input, ABS_MT_POSITION_X) || 223 !input_abs_get_max(input, ABS_MT_POSITION_Y)) { 224 dev_err(dev, "Error touchscreen-size-x and/or -y missing\n"); 225 return -EINVAL; 226 } 227 228 error = input_mt_init_slots(input, ICN8318_MAX_TOUCHES, 229 INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED); 230 if (error) 231 return error; 232 233 data->client = client; 234 data->input = input; 235 input_set_drvdata(input, data); 236 237 error = devm_request_threaded_irq(dev, client->irq, NULL, icn8318_irq, 238 IRQF_ONESHOT, client->name, data); 239 if (error) { 240 dev_err(dev, "Error requesting irq: %d\n", error); 241 return error; 242 } 243 244 /* Stop device till opened */ 245 icn8318_stop(data->input); 246 247 error = input_register_device(input); 248 if (error) 249 return error; 250 251 i2c_set_clientdata(client, data); 252 253 return 0; 254 } 255 256 static const struct of_device_id icn8318_of_match[] = { 257 { .compatible = "chipone,icn8318" }, 258 { } 259 }; 260 MODULE_DEVICE_TABLE(of, icn8318_of_match); 261 262 /* This is useless for OF-enabled devices, but it is needed by I2C subsystem */ 263 static const struct i2c_device_id icn8318_i2c_id[] = { 264 { }, 265 }; 266 MODULE_DEVICE_TABLE(i2c, icn8318_i2c_id); 267 268 static struct i2c_driver icn8318_driver = { 269 .driver = { 270 .name = "chipone_icn8318", 271 .pm = &icn8318_pm_ops, 272 .of_match_table = icn8318_of_match, 273 }, 274 .probe = icn8318_probe, 275 .id_table = icn8318_i2c_id, 276 }; 277 278 module_i2c_driver(icn8318_driver); 279 280 MODULE_DESCRIPTION("ChipOne icn8318 I2C Touchscreen Driver"); 281 MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>"); 282 MODULE_LICENSE("GPL"); 283