Quelle  wacom_i2c.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Wacom Penabled Driver for I2C
 *
 * Copyright (c) 2011 - 2013 Tatsunosuke Tobita, Wacom.
 * <tobita.tatsunosuke@wacom.co.jp>
 */

#include <linux/bits.h>
#include <linux/module.h>
#include <linux/input.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/unaligned.h>

/* Bitmasks (for data[3]) */
#define WACOM_TIP_SWITCH BIT(0)
#define WACOM_BARREL_SWITCH BIT(1)
#define WACOM_ERASER  BIT(2)
#define WACOM_INVERT  BIT(3)
#define WACOM_BARREL_SWITCH_2 BIT(4)
#define WACOM_IN_PROXIMITY BIT(5)

/* Registers */
#define WACOM_COMMAND_LSB 0x04
#define WACOM_COMMAND_MSB 0x00

#define WACOM_DATA_LSB  0x05
#define WACOM_DATA_MSB  0x00

/* Report types */
#define REPORT_FEATURE  0x30

/* Requests / operations */
#define OPCODE_GET_REPORT 0x02

#define WACOM_QUERY_REPORT 3
#define WACOM_QUERY_SIZE 19

struct wacom_features {
 int x_max;
 int y_max;
 int pressure_max;
 char fw_version;
};

struct wacom_i2c {
 struct i2c_client *client;
 struct input_dev *input;
 u8 data[WACOM_QUERY_SIZE];
 bool prox;
 int tool;
};

static int wacom_query_device(struct i2c_client *client,
         struct wacom_features *features)
{
 u8 get_query_data_cmd[] = {
  WACOM_COMMAND_LSB,
  WACOM_COMMAND_MSB,
  REPORT_FEATURE | WACOM_QUERY_REPORT,
  OPCODE_GET_REPORT,
  WACOM_DATA_LSB,
  WACOM_DATA_MSB,
 };
 u8 data[WACOM_QUERY_SIZE];
 int ret;

 struct i2c_msg msgs[] = {
  /* Request reading of feature ReportID: 3 (Pen Query Data) */
  {
   .addr = client->addr,
   .flags = 0,
   .len = sizeof(get_query_data_cmd),
   .buf = get_query_data_cmd,
  },
  {
   .addr = client->addr,
   .flags = I2C_M_RD,
   .len = sizeof(data),
   .buf = data,
  },
 };

 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
 if (ret < 0)
  return ret;
 if (ret != ARRAY_SIZE(msgs))
  return -EIO;

 features->x_max = get_unaligned_le16(&data[3]);
 features->y_max = get_unaligned_le16(&data[5]);
 features->pressure_max = get_unaligned_le16(&data[11]);
 features->fw_version = get_unaligned_le16(&data[13]);

 dev_dbg(&client->dev,
  "x_max:%d, y_max:%d, pressure:%d, fw:%d\n",
  features->x_max, features->y_max,
  features->pressure_max, features->fw_version);

 return 0;
}

static irqreturn_t wacom_i2c_irq(int irq, void *dev_id)
{
 struct wacom_i2c *wac_i2c = dev_id;
 struct input_dev *input = wac_i2c->input;
 u8 *data = wac_i2c->data;
 unsigned int x, y, pressure;
 unsigned char tsw, f1, f2, ers;
 int error;

 error = i2c_master_recv(wac_i2c->client,
    wac_i2c->data, sizeof(wac_i2c->data));
 if (error < 0)
  goto out;

 tsw = data[3] & WACOM_TIP_SWITCH;
 ers = data[3] & WACOM_ERASER;
 f1 = data[3] & WACOM_BARREL_SWITCH;
 f2 = data[3] & WACOM_BARREL_SWITCH_2;
 x = le16_to_cpup((__le16 *)&data[4]);
 y = le16_to_cpup((__le16 *)&data[6]);
 pressure = le16_to_cpup((__le16 *)&data[8]);

 if (!wac_i2c->prox)
  wac_i2c->tool = (data[3] & (WACOM_ERASER | WACOM_INVERT)) ?
   BTN_TOOL_RUBBER : BTN_TOOL_PEN;

 wac_i2c->prox = data[3] & WACOM_IN_PROXIMITY;

 input_report_key(input, BTN_TOUCH, tsw || ers);
 input_report_key(input, wac_i2c->tool, wac_i2c->prox);
 input_report_key(input, BTN_STYLUS, f1);
 input_report_key(input, BTN_STYLUS2, f2);
 input_report_abs(input, ABS_X, x);
 input_report_abs(input, ABS_Y, y);
 input_report_abs(input, ABS_PRESSURE, pressure);
 input_sync(input);

out:
 return IRQ_HANDLED;
}

static int wacom_i2c_open(struct input_dev *dev)
{
 struct wacom_i2c *wac_i2c = input_get_drvdata(dev);
 struct i2c_client *client = wac_i2c->client;

 enable_irq(client->irq);

 return 0;
}

static void wacom_i2c_close(struct input_dev *dev)
{
 struct wacom_i2c *wac_i2c = input_get_drvdata(dev);
 struct i2c_client *client = wac_i2c->client;

 disable_irq(client->irq);
}

static int wacom_i2c_probe(struct i2c_client *client)
{
 struct device *dev = &client->dev;
 struct wacom_i2c *wac_i2c;
 struct input_dev *input;
 struct wacom_features features = { 0 };
 int error;

 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
  dev_err(dev, "i2c_check_functionality error\n");
  return -EIO;
 }

 error = wacom_query_device(client, &features);
 if (error)
  return error;

 wac_i2c = devm_kzalloc(dev, sizeof(*wac_i2c), GFP_KERNEL);
 if (!wac_i2c)
  return -ENOMEM;

 wac_i2c->client = client;

 input = devm_input_allocate_device(dev);
 if (!input)
  return -ENOMEM;

 wac_i2c->input = input;

 input->name = "Wacom I2C Digitizer";
 input->id.bustype = BUS_I2C;
 input->id.vendor = 0x56a;
 input->id.version = features.fw_version;
 input->open = wacom_i2c_open;
 input->close = wacom_i2c_close;

 input->evbit[0] |= BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);

 __set_bit(BTN_TOOL_PEN, input->keybit);
 __set_bit(BTN_TOOL_RUBBER, input->keybit);
 __set_bit(BTN_STYLUS, input->keybit);
 __set_bit(BTN_STYLUS2, input->keybit);
 __set_bit(BTN_TOUCH, input->keybit);

 input_set_abs_params(input, ABS_X, 0, features.x_max, 0, 0);
 input_set_abs_params(input, ABS_Y, 0, features.y_max, 0, 0);
 input_set_abs_params(input, ABS_PRESSURE,
        0, features.pressure_max, 0, 0);

 input_set_drvdata(input, wac_i2c);

 error = devm_request_threaded_irq(dev, client->irq, NULL, wacom_i2c_irq,
       IRQF_ONESHOT, "wacom_i2c", wac_i2c);
 if (error) {
  dev_err(dev, "Failed to request IRQ: %d\n", error);
  return error;
 }

 /* Disable the IRQ, we'll enable it in wac_i2c_open() */
 disable_irq(client->irq);

 error = input_register_device(wac_i2c->input);
 if (error) {
  dev_err(dev, "Failed to register input device: %d\n", error);
  return error;
 }

 return 0;
}

static int wacom_i2c_suspend(struct device *dev)
{
 struct i2c_client *client = to_i2c_client(dev);

 disable_irq(client->irq);

 return 0;
}

static int wacom_i2c_resume(struct device *dev)
{
 struct i2c_client *client = to_i2c_client(dev);

 enable_irq(client->irq);

 return 0;
}

static DEFINE_SIMPLE_DEV_PM_OPS(wacom_i2c_pm, wacom_i2c_suspend, wacom_i2c_resume);

static const struct i2c_device_id wacom_i2c_id[] = {
 { "WAC_I2C_EMR" },
 { }
};
MODULE_DEVICE_TABLE(i2c, wacom_i2c_id);

static struct i2c_driver wacom_i2c_driver = {
 .driver = {
  .name = "wacom_i2c",
  .pm = pm_sleep_ptr(&wacom_i2c_pm),
 },

 .probe  = wacom_i2c_probe,
 .id_table = wacom_i2c_id,
};
module_i2c_driver(wacom_i2c_driver);

MODULE_AUTHOR("Tatsunosuke Tobita ");
MODULE_DESCRIPTION("WACOM EMR I2C Driver");
MODULE_LICENSE("GPL");