1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Driver for ChipOne icn8318 i2c touchscreen controller 4 * 5 * Copyright (c) 2015 Red Hat Inc. 6 * 7 * Red Hat authors: 8 * Hans de Goede <hdegoede@redhat.com> 9 */ 10 11 #include <linux/gpio/consumer.h> 12 #include <linux/interrupt.h> 13 #include <linux/i2c.h> 14 #include <linux/input.h> 15 #include <linux/input/mt.h> 16 #include <linux/input/touchscreen.h> 17 #include <linux/module.h> 18 #include <linux/of.h> 19 20 #define ICN8318_REG_POWER 4 21 #define ICN8318_REG_TOUCHDATA 16 22 23 #define ICN8318_POWER_ACTIVE 0 24 #define ICN8318_POWER_MONITOR 1 25 #define ICN8318_POWER_HIBERNATE 2 26 27 #define ICN8318_MAX_TOUCHES 5 28 29 struct icn8318_touch { 30 __u8 slot; 31 __be16 x; 32 __be16 y; 33 __u8 pressure; /* Seems more like finger width then pressure really */ 34 __u8 event; 35 /* The difference between 2 and 3 is unclear */ 36 #define ICN8318_EVENT_NO_DATA 1 /* No finger seen yet since wakeup */ 37 #define ICN8318_EVENT_UPDATE1 2 /* New or updated coordinates */ 38 #define ICN8318_EVENT_UPDATE2 3 /* New or updated coordinates */ 39 #define ICN8318_EVENT_END 4 /* Finger lifted */ 40 } __packed; 41 42 struct icn8318_touch_data { 43 __u8 softbutton; 44 __u8 touch_count; 45 struct icn8318_touch touches[ICN8318_MAX_TOUCHES]; 46 } __packed; 47 48 struct icn8318_data { 49 struct i2c_client *client; 50 struct input_dev *input; 51 struct gpio_desc *wake_gpio; 52 struct touchscreen_properties prop; 53 }; 54 55 static int icn8318_read_touch_data(struct i2c_client *client, 56 struct icn8318_touch_data *touch_data) 57 { 58 u8 reg = ICN8318_REG_TOUCHDATA; 59 struct i2c_msg msg[2] = { 60 { 61 .addr = client->addr, 62 .len = 1, 63 .buf = ® 64 }, 65 { 66 .addr = client->addr, 67 .flags = I2C_M_RD, 68 .len = sizeof(struct icn8318_touch_data), 69 .buf = (u8 *)touch_data 70 } 71 }; 72 73 return i2c_transfer(client->adapter, msg, 2); 74 } 75 76 static inline bool icn8318_touch_active(u8 event) 77 { 78 return (event == ICN8318_EVENT_UPDATE1) || 79 (event == ICN8318_EVENT_UPDATE2); 80 } 81 82 static irqreturn_t icn8318_irq(int irq, void *dev_id) 83 { 84 struct icn8318_data *data = dev_id; 85 struct device *dev = &data->client->dev; 86 struct icn8318_touch_data touch_data; 87 int i, ret; 88 89 ret = icn8318_read_touch_data(data->client, &touch_data); 90 if (ret < 0) { 91 dev_err(dev, "Error reading touch data: %d\n", ret); 92 return IRQ_HANDLED; 93 } 94 95 if (touch_data.softbutton) { 96 /* 97 * Other data is invalid when a softbutton is pressed. 98 * This needs some extra devicetree bindings to map the icn8318 99 * softbutton codes to evdev codes. Currently no known devices 100 * use this. 101 */ 102 return IRQ_HANDLED; 103 } 104 105 if (touch_data.touch_count > ICN8318_MAX_TOUCHES) { 106 dev_warn(dev, "Too much touches %d > %d\n", 107 touch_data.touch_count, ICN8318_MAX_TOUCHES); 108 touch_data.touch_count = ICN8318_MAX_TOUCHES; 109 } 110 111 for (i = 0; i < touch_data.touch_count; i++) { 112 struct icn8318_touch *touch = &touch_data.touches[i]; 113 bool act = icn8318_touch_active(touch->event); 114 115 input_mt_slot(data->input, touch->slot); 116 input_mt_report_slot_state(data->input, MT_TOOL_FINGER, act); 117 if (!act) 118 continue; 119 120 touchscreen_report_pos(data->input, &data->prop, 121 be16_to_cpu(touch->x), 122 be16_to_cpu(touch->y), true); 123 } 124 125 input_mt_sync_frame(data->input); 126 input_sync(data->input); 127 128 return IRQ_HANDLED; 129 } 130 131 static int icn8318_start(struct input_dev *dev) 132 { 133 struct icn8318_data *data = input_get_drvdata(dev); 134 135 enable_irq(data->client->irq); 136 gpiod_set_value_cansleep(data->wake_gpio, 1); 137 138 return 0; 139 } 140 141 static void icn8318_stop(struct input_dev *dev) 142 { 143 struct icn8318_data *data = input_get_drvdata(dev); 144 145 disable_irq(data->client->irq); 146 i2c_smbus_write_byte_data(data->client, ICN8318_REG_POWER, 147 ICN8318_POWER_HIBERNATE); 148 gpiod_set_value_cansleep(data->wake_gpio, 0); 149 } 150 151 static int icn8318_suspend(struct device *dev) 152 { 153 struct icn8318_data *data = i2c_get_clientdata(to_i2c_client(dev)); 154 155 mutex_lock(&data->input->mutex); 156 if (input_device_enabled(data->input)) 157 icn8318_stop(data->input); 158 mutex_unlock(&data->input->mutex); 159 160 return 0; 161 } 162 163 static int icn8318_resume(struct device *dev) 164 { 165 struct icn8318_data *data = i2c_get_clientdata(to_i2c_client(dev)); 166 167 mutex_lock(&data->input->mutex); 168 if (input_device_enabled(data->input)) 169 icn8318_start(data->input); 170 mutex_unlock(&data->input->mutex); 171 172 return 0; 173 } 174 175 static DEFINE_SIMPLE_DEV_PM_OPS(icn8318_pm_ops, icn8318_suspend, icn8318_resume); 176 177 static int icn8318_probe(struct i2c_client *client) 178 { 179 struct device *dev = &client->dev; 180 struct icn8318_data *data; 181 struct input_dev *input; 182 int error; 183 184 if (!client->irq) { 185 dev_err(dev, "Error no irq specified\n"); 186 return -EINVAL; 187 } 188 189 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); 190 if (!data) 191 return -ENOMEM; 192 193 data->wake_gpio = devm_gpiod_get(dev, "wake", GPIOD_OUT_LOW); 194 if (IS_ERR(data->wake_gpio)) 195 return dev_err_probe(dev, PTR_ERR(data->wake_gpio), "Error getting wake gpio\n"); 196 197 input = devm_input_allocate_device(dev); 198 if (!input) 199 return -ENOMEM; 200 201 input->name = client->name; 202 input->id.bustype = BUS_I2C; 203 input->open = icn8318_start; 204 input->close = icn8318_stop; 205 input->dev.parent = dev; 206 207 input_set_capability(input, EV_ABS, ABS_MT_POSITION_X); 208 input_set_capability(input, EV_ABS, ABS_MT_POSITION_Y); 209 210 touchscreen_parse_properties(input, true, &data->prop); 211 if (!input_abs_get_max(input, ABS_MT_POSITION_X) || 212 !input_abs_get_max(input, ABS_MT_POSITION_Y)) { 213 dev_err(dev, "Error touchscreen-size-x and/or -y missing\n"); 214 return -EINVAL; 215 } 216 217 error = input_mt_init_slots(input, ICN8318_MAX_TOUCHES, 218 INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED); 219 if (error) 220 return error; 221 222 data->client = client; 223 data->input = input; 224 input_set_drvdata(input, data); 225 226 error = devm_request_threaded_irq(dev, client->irq, NULL, icn8318_irq, 227 IRQF_ONESHOT, client->name, data); 228 if (error) { 229 dev_err(dev, "Error requesting irq: %d\n", error); 230 return error; 231 } 232 233 /* Stop device till opened */ 234 icn8318_stop(data->input); 235 236 error = input_register_device(input); 237 if (error) 238 return error; 239 240 i2c_set_clientdata(client, data); 241 242 return 0; 243 } 244 245 static const struct of_device_id icn8318_of_match[] = { 246 { .compatible = "chipone,icn8318" }, 247 { } 248 }; 249 MODULE_DEVICE_TABLE(of, icn8318_of_match); 250 251 /* This is useless for OF-enabled devices, but it is needed by I2C subsystem */ 252 static const struct i2c_device_id icn8318_i2c_id[] = { 253 { }, 254 }; 255 MODULE_DEVICE_TABLE(i2c, icn8318_i2c_id); 256 257 static struct i2c_driver icn8318_driver = { 258 .driver = { 259 .name = "chipone_icn8318", 260 .pm = pm_sleep_ptr(&icn8318_pm_ops), 261 .of_match_table = icn8318_of_match, 262 }, 263 .probe = icn8318_probe, 264 .id_table = icn8318_i2c_id, 265 }; 266 267 module_i2c_driver(icn8318_driver); 268 269 MODULE_DESCRIPTION("ChipOne icn8318 I2C Touchscreen Driver"); 270 MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>"); 271 MODULE_LICENSE("GPL"); 272