1/*
  2 * Microchip 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/module.h>
 10#include <linux/input.h>
 11#include <linux/of.h>
 12#include <linux/i2c.h>
 13#include <linux/irq.h>
 14#include <linux/interrupt.h>
 15
 16#define AR1021_TOCUH_PKG_SIZE	5
 17
 18#define AR1021_MAX_X	4095
 19#define AR1021_MAX_Y	4095
 20
 21struct ar1021_i2c {
 22	struct i2c_client *client;
 23	struct input_dev *input;
 24	u8 data[AR1021_TOCUH_PKG_SIZE];
 25};
 26
 27static irqreturn_t ar1021_i2c_irq(int irq, void *dev_id)
 28{
 29	struct ar1021_i2c *ar1021 = dev_id;
 30	struct input_dev *input = ar1021->input;
 31	u8 *data = ar1021->data;
 32	unsigned int x, y, button;
 33	int retval;
 34
 35	retval = i2c_master_recv(ar1021->client,
 36				ar1021->data, sizeof(ar1021->data));
 37	if (retval != sizeof(ar1021->data))
 38		goto out;
 39
 40	/* sync bit set ? */
 41	if ((data[0] & 0x80) == 0)
 42		goto out;
 43
 44	button = data[0] & BIT(0);
 45	x = ((data[2] & 0x1f) << 7) | (data[1] & 0x7f);
 46	y = ((data[4] & 0x1f) << 7) | (data[3] & 0x7f);
 47
 48	input_report_abs(input, ABS_X, x);
 49	input_report_abs(input, ABS_Y, y);
 50	input_report_key(input, BTN_TOUCH, button);
 51	input_sync(input);
 52
 53out:
 54	return IRQ_HANDLED;
 55}
 56
 57static int ar1021_i2c_open(struct input_dev *dev)
 58{
 59	struct ar1021_i2c *ar1021 = input_get_drvdata(dev);
 60	struct i2c_client *client = ar1021->client;
 61
 62	enable_irq(client->irq);
 63
 64	return 0;
 65}
 66
 67static void ar1021_i2c_close(struct input_dev *dev)
 68{
 69	struct ar1021_i2c *ar1021 = input_get_drvdata(dev);
 70	struct i2c_client *client = ar1021->client;
 71
 72	disable_irq(client->irq);
 73}
 74
 75static int ar1021_i2c_probe(struct i2c_client *client,
 76				     const struct i2c_device_id *id)
 77{
 78	struct ar1021_i2c *ar1021;
 79	struct input_dev *input;
 80	int error;
 81
 82	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 83		dev_err(&client->dev, "i2c_check_functionality error\n");
 84		return -ENXIO;
 85	}
 86
 87	ar1021 = devm_kzalloc(&client->dev, sizeof(*ar1021), GFP_KERNEL);
 88	if (!ar1021)
 89		return -ENOMEM;
 90
 91	input = devm_input_allocate_device(&client->dev);
 92	if (!input)
 93		return -ENOMEM;
 94
 95	ar1021->client = client;
 96	ar1021->input = input;
 97
 98	input->name = "ar1021 I2C Touchscreen";
 99	input->id.bustype = BUS_I2C;
100	input->dev.parent = &client->dev;
101	input->open = ar1021_i2c_open;
102	input->close = ar1021_i2c_close;
103
104	input_set_capability(input, EV_KEY, BTN_TOUCH);
105	input_set_abs_params(input, ABS_X, 0, AR1021_MAX_X, 0, 0);
106	input_set_abs_params(input, ABS_Y, 0, AR1021_MAX_Y, 0, 0);
107
108	input_set_drvdata(input, ar1021);
109
110	error = devm_request_threaded_irq(&client->dev, client->irq,
111					  NULL, ar1021_i2c_irq,
112					  IRQF_TRIGGER_RISING | IRQF_ONESHOT,
113					  "ar1021_i2c", ar1021);
114	if (error) {
115		dev_err(&client->dev,
116			"Failed to enable IRQ, error: %d\n", error);
117		return error;
118	}
119
120	/* Disable the IRQ, we'll enable it in ar1021_i2c_open() */
121	disable_irq(client->irq);
122
123	error = input_register_device(ar1021->input);
124	if (error) {
125		dev_err(&client->dev,
126			"Failed to register input device, error: %d\n", error);
127		return error;
128	}
129
130	i2c_set_clientdata(client, ar1021);
131	return 0;
132}
133
134static int __maybe_unused ar1021_i2c_suspend(struct device *dev)
135{
136	struct i2c_client *client = to_i2c_client(dev);
137
138	disable_irq(client->irq);
139
140	return 0;
141}
142
143static int __maybe_unused ar1021_i2c_resume(struct device *dev)
144{
145	struct i2c_client *client = to_i2c_client(dev);
146
147	enable_irq(client->irq);
148
149	return 0;
150}
151
152static SIMPLE_DEV_PM_OPS(ar1021_i2c_pm, ar1021_i2c_suspend, ar1021_i2c_resume);
153
154static const struct i2c_device_id ar1021_i2c_id[] = {
155	{ "MICROCHIP_AR1021_I2C", 0 },
156	{ },
157};
158MODULE_DEVICE_TABLE(i2c, ar1021_i2c_id);
159
160static const struct of_device_id ar1021_i2c_of_match[] = {
161	{ .compatible = "microchip,ar1021-i2c", },
162	{ }
163};
164MODULE_DEVICE_TABLE(of, ar1021_i2c_of_match);
165
166static struct i2c_driver ar1021_i2c_driver = {
167	.driver	= {
168		.name	= "ar1021_i2c",
169		.pm	= &ar1021_i2c_pm,
170		.of_match_table = ar1021_i2c_of_match,
171	},
172
173	.probe		= ar1021_i2c_probe,
174	.id_table	= ar1021_i2c_id,
175};
176module_i2c_driver(ar1021_i2c_driver);
177
178MODULE_AUTHOR("Christian Gmeiner <christian.gmeiner@gmail.com>");
179MODULE_DESCRIPTION("Microchip AR1021 I2C Driver");
180MODULE_LICENSE("GPL");