summaryrefslogtreecommitdiffstats
path: root/drivers/input/joystick/adc-joystick.c
blob: e0cfdc84763f417795641de2d6b6ee5a6d426898 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
// SPDX-License-Identifier: GPL-2.0
/*
 * Input driver for joysticks connected over ADC.
 * Copyright (c) 2019-2020 Artur Rojek <contact@artur-rojek.eu>
 */
#include <linux/ctype.h>
#include <linux/input.h>
#include <linux/iio/iio.h>
#include <linux/iio/consumer.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/property.h>

#include <asm/unaligned.h>

struct adc_joystick_axis {
	u32 code;
	s32 range[2];
	s32 fuzz;
	s32 flat;
};

struct adc_joystick {
	struct input_dev *input;
	struct iio_cb_buffer *buffer;
	struct adc_joystick_axis *axes;
	struct iio_channel *chans;
	int num_chans;
};

static int adc_joystick_handle(const void *data, void *private)
{
	struct adc_joystick *joy = private;
	enum iio_endian endianness;
	int bytes, msb, val, idx, i;
	const u16 *data_u16;
	bool sign;

	bytes = joy->chans[0].channel->scan_type.storagebits >> 3;

	for (i = 0; i < joy->num_chans; ++i) {
		idx = joy->chans[i].channel->scan_index;
		endianness = joy->chans[i].channel->scan_type.endianness;
		msb = joy->chans[i].channel->scan_type.realbits - 1;
		sign = tolower(joy->chans[i].channel->scan_type.sign) == 's';

		switch (bytes) {
		case 1:
			val = ((const u8 *)data)[idx];
			break;
		case 2:
			data_u16 = (const u16 *)data + idx;

			/*
			 * Data is aligned to the sample size by IIO core.
			 * Call `get_unaligned_xe16` to hide type casting.
			 */
			if (endianness == IIO_BE)
				val = get_unaligned_be16(data_u16);
			else if (endianness == IIO_LE)
				val = get_unaligned_le16(data_u16);
			else /* IIO_CPU */
				val = *data_u16;
			break;
		default:
			return -EINVAL;
		}

		val >>= joy->chans[i].channel->scan_type.shift;
		if (sign)
			val = sign_extend32(val, msb);
		else
			val &= GENMASK(msb, 0);
		input_report_abs(joy->input, joy->axes[i].code, val);
	}

	input_sync(joy->input);

	return 0;
}

static int adc_joystick_open(struct input_dev *dev)
{
	struct adc_joystick *joy = input_get_drvdata(dev);
	struct device *devp = &dev->dev;
	int ret;

	ret = iio_channel_start_all_cb(joy->buffer);
	if (ret)
		dev_err(devp, "Unable to start callback buffer: %d\n", ret);

	return ret;
}

static void adc_joystick_close(struct input_dev *dev)
{
	struct adc_joystick *joy = input_get_drvdata(dev);

	iio_channel_stop_all_cb(joy->buffer);
}

static void adc_joystick_cleanup(void *data)
{
	iio_channel_release_all_cb(data);
}

static int adc_joystick_set_axes(struct device *dev, struct adc_joystick *joy)
{
	struct adc_joystick_axis *axes;
	struct fwnode_handle *child;
	int num_axes, error, i;

	num_axes = device_get_child_node_count(dev);
	if (!num_axes) {
		dev_err(dev, "Unable to find child nodes\n");
		return -EINVAL;
	}

	if (num_axes != joy->num_chans) {
		dev_err(dev, "Got %d child nodes for %d channels\n",
			num_axes, joy->num_chans);
		return -EINVAL;
	}

	axes = devm_kmalloc_array(dev, num_axes, sizeof(*axes), GFP_KERNEL);
	if (!axes)
		return -ENOMEM;

	device_for_each_child_node(dev, child) {
		error = fwnode_property_read_u32(child, "reg", &i);
		if (error) {
			dev_err(dev, "reg invalid or missing\n");
			goto err_fwnode_put;
		}

		if (i >= num_axes) {
			error = -EINVAL;
			dev_err(dev, "No matching axis for reg %d\n", i);
			goto err_fwnode_put;
		}

		error = fwnode_property_read_u32(child, "linux,code",
						 &axes[i].code);
		if (error) {
			dev_err(dev, "linux,code invalid or missing\n");
			goto err_fwnode_put;
		}

		error = fwnode_property_read_u32_array(child, "abs-range",
						       axes[i].range, 2);
		if (error) {
			dev_err(dev, "abs-range invalid or missing\n");
			goto err_fwnode_put;
		}

		fwnode_property_read_u32(child, "abs-fuzz", &axes[i].fuzz);
		fwnode_property_read_u32(child, "abs-flat", &axes[i].flat);

		input_set_abs_params(joy->input, axes[i].code,
				     axes[i].range[0], axes[i].range[1],
				     axes[i].fuzz, axes[i].flat);
		input_set_capability(joy->input, EV_ABS, axes[i].code);
	}

	joy->axes = axes;

	return 0;

err_fwnode_put:
	fwnode_handle_put(child);
	return error;
}

static int adc_joystick_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct adc_joystick *joy;
	struct input_dev *input;
	int error;
	int bits;
	int i;

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

	joy->chans = devm_iio_channel_get_all(dev);
	if (IS_ERR(joy->chans)) {
		error = PTR_ERR(joy->chans);
		if (error != -EPROBE_DEFER)
			dev_err(dev, "Unable to get IIO channels");
		return error;
	}

	/* Count how many channels we got. NULL terminated. */
	for (i = 0; joy->chans[i].indio_dev; i++) {
		bits = joy->chans[i].channel->scan_type.storagebits;
		if (!bits || bits > 16) {
			dev_err(dev, "Unsupported channel storage size\n");
			return -EINVAL;
		}
		if (bits != joy->chans[0].channel->scan_type.storagebits) {
			dev_err(dev, "Channels must have equal storage size\n");
			return -EINVAL;
		}
	}
	joy->num_chans = i;

	input = devm_input_allocate_device(dev);
	if (!input) {
		dev_err(dev, "Unable to allocate input device\n");
		return -ENOMEM;
	}

	joy->input = input;
	input->name = pdev->name;
	input->id.bustype = BUS_HOST;
	input->open = adc_joystick_open;
	input->close = adc_joystick_close;

	error = adc_joystick_set_axes(dev, joy);
	if (error)
		return error;

	joy->buffer = iio_channel_get_all_cb(dev, adc_joystick_handle, joy);
	if (IS_ERR(joy->buffer)) {
		dev_err(dev, "Unable to allocate callback buffer\n");
		return PTR_ERR(joy->buffer);
	}

	error = devm_add_action_or_reset(dev, adc_joystick_cleanup, joy->buffer);
	if (error)  {
		dev_err(dev, "Unable to add action\n");
		return error;
	}

	input_set_drvdata(input, joy);

	error = input_register_device(input);
	if (error) {
		dev_err(dev, "Unable to register input device\n");
		return error;
	}

	return 0;
}

static const struct of_device_id adc_joystick_of_match[] = {
	{ .compatible = "adc-joystick", },
	{ }
};
MODULE_DEVICE_TABLE(of, adc_joystick_of_match);

static struct platform_driver adc_joystick_driver = {
	.driver = {
		.name = "adc-joystick",
		.of_match_table = adc_joystick_of_match,
	},
	.probe = adc_joystick_probe,
};
module_platform_driver(adc_joystick_driver);

MODULE_DESCRIPTION("Input driver for joysticks connected over ADC");
MODULE_AUTHOR("Artur Rojek <contact@artur-rojek.eu>");
MODULE_LICENSE("GPL");