1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Microchip AR1020 and AR1021 driver for I2C
4  *
5  * Author: Christian Gmeiner <christian.gmeiner@gmail.com>
6  */
7 
8 #include <linux/bitops.h>
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_TOUCH_PKG_SIZE	5
17 
18 #define AR1021_MAX_X	4095
19 #define AR1021_MAX_Y	4095
20 
21 #define AR1021_CMD	0x55
22 
23 #define AR1021_CMD_ENABLE_TOUCH		0x12
24 
25 struct ar1021_i2c {
26 	struct i2c_client *client;
27 	struct input_dev *input;
28 	u8 data[AR1021_TOUCH_PKG_SIZE];
29 };
30 
31 static irqreturn_t ar1021_i2c_irq(int irq, void *dev_id)
32 {
33 	struct ar1021_i2c *ar1021 = dev_id;
34 	struct input_dev *input = ar1021->input;
35 	u8 *data = ar1021->data;
36 	unsigned int x, y, button;
37 	int retval;
38 
39 	retval = i2c_master_recv(ar1021->client,
40 				 ar1021->data, sizeof(ar1021->data));
41 	if (retval != sizeof(ar1021->data))
42 		goto out;
43 
44 	/* sync bit set ? */
45 	if (!(data[0] & BIT(7)))
46 		goto out;
47 
48 	button = data[0] & BIT(0);
49 	x = ((data[2] & 0x1f) << 7) | (data[1] & 0x7f);
50 	y = ((data[4] & 0x1f) << 7) | (data[3] & 0x7f);
51 
52 	input_report_abs(input, ABS_X, x);
53 	input_report_abs(input, ABS_Y, y);
54 	input_report_key(input, BTN_TOUCH, button);
55 	input_sync(input);
56 
57 out:
58 	return IRQ_HANDLED;
59 }
60 
61 static int ar1021_i2c_open(struct input_dev *dev)
62 {
63 	static const u8 cmd_enable_touch[] = {
64 		AR1021_CMD,
65 		0x01, /* number of bytes after this */
66 		AR1021_CMD_ENABLE_TOUCH
67 	};
68 	struct ar1021_i2c *ar1021 = input_get_drvdata(dev);
69 	struct i2c_client *client = ar1021->client;
70 	int error;
71 
72 	error = i2c_master_send(ar1021->client, cmd_enable_touch,
73 				sizeof(cmd_enable_touch));
74 	if (error < 0)
75 		return error;
76 
77 	enable_irq(client->irq);
78 
79 	return 0;
80 }
81 
82 static void ar1021_i2c_close(struct input_dev *dev)
83 {
84 	struct ar1021_i2c *ar1021 = input_get_drvdata(dev);
85 	struct i2c_client *client = ar1021->client;
86 
87 	disable_irq(client->irq);
88 }
89 
90 static int ar1021_i2c_probe(struct i2c_client *client,
91 			    const struct i2c_device_id *id)
92 {
93 	struct ar1021_i2c *ar1021;
94 	struct input_dev *input;
95 	int error;
96 
97 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
98 		dev_err(&client->dev, "i2c_check_functionality error\n");
99 		return -ENXIO;
100 	}
101 
102 	ar1021 = devm_kzalloc(&client->dev, sizeof(*ar1021), GFP_KERNEL);
103 	if (!ar1021)
104 		return -ENOMEM;
105 
106 	input = devm_input_allocate_device(&client->dev);
107 	if (!input)
108 		return -ENOMEM;
109 
110 	ar1021->client = client;
111 	ar1021->input = input;
112 
113 	input->name = "ar1021 I2C Touchscreen";
114 	input->id.bustype = BUS_I2C;
115 	input->dev.parent = &client->dev;
116 	input->open = ar1021_i2c_open;
117 	input->close = ar1021_i2c_close;
118 
119 	__set_bit(INPUT_PROP_DIRECT, input->propbit);
120 	input_set_capability(input, EV_KEY, BTN_TOUCH);
121 	input_set_abs_params(input, ABS_X, 0, AR1021_MAX_X, 0, 0);
122 	input_set_abs_params(input, ABS_Y, 0, AR1021_MAX_Y, 0, 0);
123 
124 	input_set_drvdata(input, ar1021);
125 
126 	error = devm_request_threaded_irq(&client->dev, client->irq,
127 					  NULL, ar1021_i2c_irq,
128 					  IRQF_ONESHOT,
129 					  "ar1021_i2c", ar1021);
130 	if (error) {
131 		dev_err(&client->dev,
132 			"Failed to enable IRQ, error: %d\n", error);
133 		return error;
134 	}
135 
136 	/* Disable the IRQ, we'll enable it in ar1021_i2c_open() */
137 	disable_irq(client->irq);
138 
139 	error = input_register_device(ar1021->input);
140 	if (error) {
141 		dev_err(&client->dev,
142 			"Failed to register input device, error: %d\n", error);
143 		return error;
144 	}
145 
146 	return 0;
147 }
148 
149 static int __maybe_unused ar1021_i2c_suspend(struct device *dev)
150 {
151 	struct i2c_client *client = to_i2c_client(dev);
152 
153 	disable_irq(client->irq);
154 
155 	return 0;
156 }
157 
158 static int __maybe_unused ar1021_i2c_resume(struct device *dev)
159 {
160 	struct i2c_client *client = to_i2c_client(dev);
161 
162 	enable_irq(client->irq);
163 
164 	return 0;
165 }
166 
167 static SIMPLE_DEV_PM_OPS(ar1021_i2c_pm, ar1021_i2c_suspend, ar1021_i2c_resume);
168 
169 static const struct i2c_device_id ar1021_i2c_id[] = {
170 	{ "ar1021", 0 },
171 	{ },
172 };
173 MODULE_DEVICE_TABLE(i2c, ar1021_i2c_id);
174 
175 static const struct of_device_id ar1021_i2c_of_match[] = {
176 	{ .compatible = "microchip,ar1021-i2c", },
177 	{ }
178 };
179 MODULE_DEVICE_TABLE(of, ar1021_i2c_of_match);
180 
181 static struct i2c_driver ar1021_i2c_driver = {
182 	.driver	= {
183 		.name	= "ar1021_i2c",
184 		.pm	= &ar1021_i2c_pm,
185 		.of_match_table = ar1021_i2c_of_match,
186 	},
187 
188 	.probe		= ar1021_i2c_probe,
189 	.id_table	= ar1021_i2c_id,
190 };
191 module_i2c_driver(ar1021_i2c_driver);
192 
193 MODULE_AUTHOR("Christian Gmeiner <christian.gmeiner@gmail.com>");
194 MODULE_DESCRIPTION("Microchip AR1020 and AR1021 I2C Driver");
195 MODULE_LICENSE("GPL");
196