drivers/input/touchscreen/chipone_icn8318.c

   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 = &reg
  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");