linux/drivers/input/touchscreen/ar1021_i2c.c
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   1/*
   2 * Microchip AR1020 and AR1021 driver for I2C
   3 *
   4 * Author: Christian Gmeiner <christian.gmeiner@gmail.com>
   5 *
   6 * License: GPLv2 as published by the FSF.
   7 */
   8
   9#include <linux/bitops.h>
  10#include <linux/module.h>
  11#include <linux/input.h>
  12#include <linux/of.h>
  13#include <linux/i2c.h>
  14#include <linux/irq.h>
  15#include <linux/interrupt.h>
  16
  17#define AR1021_TOCUH_PKG_SIZE   5
  18
  19#define AR1021_MAX_X    4095
  20#define AR1021_MAX_Y    4095
  21
  22#define AR1021_CMD      0x55
  23
  24#define AR1021_CMD_ENABLE_TOUCH         0x12
  25
  26struct ar1021_i2c {
  27        struct i2c_client *client;
  28        struct input_dev *input;
  29        u8 data[AR1021_TOCUH_PKG_SIZE];
  30};
  31
  32static irqreturn_t ar1021_i2c_irq(int irq, void *dev_id)
  33{
  34        struct ar1021_i2c *ar1021 = dev_id;
  35        struct input_dev *input = ar1021->input;
  36        u8 *data = ar1021->data;
  37        unsigned int x, y, button;
  38        int retval;
  39
  40        retval = i2c_master_recv(ar1021->client,
  41                                 ar1021->data, sizeof(ar1021->data));
  42        if (retval != sizeof(ar1021->data))
  43                goto out;
  44
  45        /* sync bit set ? */
  46        if (!(data[0] & BIT(7)))
  47                goto out;
  48
  49        button = data[0] & BIT(0);
  50        x = ((data[2] & 0x1f) << 7) | (data[1] & 0x7f);
  51        y = ((data[4] & 0x1f) << 7) | (data[3] & 0x7f);
  52
  53        input_report_abs(input, ABS_X, x);
  54        input_report_abs(input, ABS_Y, y);
  55        input_report_key(input, BTN_TOUCH, button);
  56        input_sync(input);
  57
  58out:
  59        return IRQ_HANDLED;
  60}
  61
  62static int ar1021_i2c_open(struct input_dev *dev)
  63{
  64        static const u8 cmd_enable_touch[] = {
  65                AR1021_CMD,
  66                0x01, /* number of bytes after this */
  67                AR1021_CMD_ENABLE_TOUCH
  68        };
  69        struct ar1021_i2c *ar1021 = input_get_drvdata(dev);
  70        struct i2c_client *client = ar1021->client;
  71        int error;
  72
  73        error = i2c_master_send(ar1021->client, cmd_enable_touch,
  74                                sizeof(cmd_enable_touch));
  75        if (error < 0)
  76                return error;
  77
  78        enable_irq(client->irq);
  79
  80        return 0;
  81}
  82
  83static void ar1021_i2c_close(struct input_dev *dev)
  84{
  85        struct ar1021_i2c *ar1021 = input_get_drvdata(dev);
  86        struct i2c_client *client = ar1021->client;
  87
  88        disable_irq(client->irq);
  89}
  90
  91static int ar1021_i2c_probe(struct i2c_client *client,
  92                            const struct i2c_device_id *id)
  93{
  94        struct ar1021_i2c *ar1021;
  95        struct input_dev *input;
  96        int error;
  97
  98        if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
  99                dev_err(&client->dev, "i2c_check_functionality error\n");
 100                return -ENXIO;
 101        }
 102
 103        ar1021 = devm_kzalloc(&client->dev, sizeof(*ar1021), GFP_KERNEL);
 104        if (!ar1021)
 105                return -ENOMEM;
 106
 107        input = devm_input_allocate_device(&client->dev);
 108        if (!input)
 109                return -ENOMEM;
 110
 111        ar1021->client = client;
 112        ar1021->input = input;
 113
 114        input->name = "ar1021 I2C Touchscreen";
 115        input->id.bustype = BUS_I2C;
 116        input->dev.parent = &client->dev;
 117        input->open = ar1021_i2c_open;
 118        input->close = ar1021_i2c_close;
 119
 120        __set_bit(INPUT_PROP_DIRECT, input->propbit);
 121        input_set_capability(input, EV_KEY, BTN_TOUCH);
 122        input_set_abs_params(input, ABS_X, 0, AR1021_MAX_X, 0, 0);
 123        input_set_abs_params(input, ABS_Y, 0, AR1021_MAX_Y, 0, 0);
 124
 125        input_set_drvdata(input, ar1021);
 126
 127        error = devm_request_threaded_irq(&client->dev, client->irq,
 128                                          NULL, ar1021_i2c_irq,
 129                                          IRQF_ONESHOT,
 130                                          "ar1021_i2c", ar1021);
 131        if (error) {
 132                dev_err(&client->dev,
 133                        "Failed to enable IRQ, error: %d\n", error);
 134                return error;
 135        }
 136
 137        /* Disable the IRQ, we'll enable it in ar1021_i2c_open() */
 138        disable_irq(client->irq);
 139
 140        error = input_register_device(ar1021->input);
 141        if (error) {
 142                dev_err(&client->dev,
 143                        "Failed to register input device, error: %d\n", error);
 144                return error;
 145        }
 146
 147        return 0;
 148}
 149
 150static int __maybe_unused ar1021_i2c_suspend(struct device *dev)
 151{
 152        struct i2c_client *client = to_i2c_client(dev);
 153
 154        disable_irq(client->irq);
 155
 156        return 0;
 157}
 158
 159static int __maybe_unused ar1021_i2c_resume(struct device *dev)
 160{
 161        struct i2c_client *client = to_i2c_client(dev);
 162
 163        enable_irq(client->irq);
 164
 165        return 0;
 166}
 167
 168static SIMPLE_DEV_PM_OPS(ar1021_i2c_pm, ar1021_i2c_suspend, ar1021_i2c_resume);
 169
 170static const struct i2c_device_id ar1021_i2c_id[] = {
 171        { "ar1021", 0 },
 172        { },
 173};
 174MODULE_DEVICE_TABLE(i2c, ar1021_i2c_id);
 175
 176static const struct of_device_id ar1021_i2c_of_match[] = {
 177        { .compatible = "microchip,ar1021-i2c", },
 178        { }
 179};
 180MODULE_DEVICE_TABLE(of, ar1021_i2c_of_match);
 181
 182static struct i2c_driver ar1021_i2c_driver = {
 183        .driver = {
 184                .name   = "ar1021_i2c",
 185                .pm     = &ar1021_i2c_pm,
 186                .of_match_table = ar1021_i2c_of_match,
 187        },
 188
 189        .probe          = ar1021_i2c_probe,
 190        .id_table       = ar1021_i2c_id,
 191};
 192module_i2c_driver(ar1021_i2c_driver);
 193
 194MODULE_AUTHOR("Christian Gmeiner <christian.gmeiner@gmail.com>");
 195MODULE_DESCRIPTION("Microchip AR1020 and AR1021 I2C Driver");
 196MODULE_LICENSE("GPL");
 197