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");