drivers/input/touchscreen/chipone_icn8318.c

   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 = &reg
  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");