summaryrefslogtreecommitdiff
path: root/drivers/iio/amplifiers/hmc425a.c
blob: 16c0a77f6a1c1fb8dbf8a9625374b39ff3e4ee93 (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
// SPDX-License-Identifier: GPL-2.0
/*
 * HMC425A and similar Gain Amplifiers
 *
 * Copyright 2020 Analog Devices Inc.
 */

#include <linux/device.h>
#include <linux/err.h>
#include <linux/gpio/consumer.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/regulator/consumer.h>
#include <linux/sysfs.h>

enum hmc425a_type {
	ID_HMC425A,
};

struct hmc425a_chip_info {
	const char			*name;
	const struct iio_chan_spec	*channels;
	unsigned int			num_channels;
	unsigned int			num_gpios;
	int				gain_min;
	int				gain_max;
	int				default_gain;
};

struct hmc425a_state {
	struct	regulator *reg;
	struct	mutex lock; /* protect sensor state */
	struct	hmc425a_chip_info *chip_info;
	struct	gpio_descs *gpios;
	enum	hmc425a_type type;
	u32	gain;
};

static int hmc425a_write(struct iio_dev *indio_dev, u32 value)
{
	struct hmc425a_state *st = iio_priv(indio_dev);
	DECLARE_BITMAP(values, BITS_PER_TYPE(value));

	values[0] = value;

	gpiod_set_array_value_cansleep(st->gpios->ndescs, st->gpios->desc,
				       NULL, values);
	return 0;
}

static int hmc425a_read_raw(struct iio_dev *indio_dev,
			    struct iio_chan_spec const *chan, int *val,
			    int *val2, long m)
{
	struct hmc425a_state *st = iio_priv(indio_dev);
	int code, gain = 0;
	int ret;

	mutex_lock(&st->lock);
	switch (m) {
	case IIO_CHAN_INFO_HARDWAREGAIN:
		code = st->gain;

		switch (st->type) {
		case ID_HMC425A:
			gain = ~code * -500;
			break;
		}

		*val = gain / 1000;
		*val2 = (gain % 1000) * 1000;

		ret = IIO_VAL_INT_PLUS_MICRO_DB;
		break;
	default:
		ret = -EINVAL;
	}
	mutex_unlock(&st->lock);

	return ret;
};

static int hmc425a_write_raw(struct iio_dev *indio_dev,
			     struct iio_chan_spec const *chan, int val,
			     int val2, long mask)
{
	struct hmc425a_state *st = iio_priv(indio_dev);
	struct hmc425a_chip_info *inf = st->chip_info;
	int code = 0, gain;
	int ret;

	if (val < 0)
		gain = (val * 1000) - (val2 / 1000);
	else
		gain = (val * 1000) + (val2 / 1000);

	if (gain > inf->gain_max || gain < inf->gain_min)
		return -EINVAL;

	switch (st->type) {
	case ID_HMC425A:
		code = ~((abs(gain) / 500) & 0x3F);
		break;
	}

	mutex_lock(&st->lock);
	switch (mask) {
	case IIO_CHAN_INFO_HARDWAREGAIN:
		st->gain = code;

		ret = hmc425a_write(indio_dev, st->gain);
		break;
	default:
		ret = -EINVAL;
	}
	mutex_unlock(&st->lock);

	return ret;
}

static int hmc425a_write_raw_get_fmt(struct iio_dev *indio_dev,
				     struct iio_chan_spec const *chan,
				     long mask)
{
	switch (mask) {
	case IIO_CHAN_INFO_HARDWAREGAIN:
		return IIO_VAL_INT_PLUS_MICRO_DB;
	default:
		return -EINVAL;
	}
}

static const struct iio_info hmc425a_info = {
	.read_raw = &hmc425a_read_raw,
	.write_raw = &hmc425a_write_raw,
	.write_raw_get_fmt = &hmc425a_write_raw_get_fmt,
};

#define HMC425A_CHAN(_channel)						\
{									\
	.type = IIO_VOLTAGE,						\
	.output = 1,							\
	.indexed = 1,							\
	.channel = _channel,						\
	.info_mask_separate = BIT(IIO_CHAN_INFO_HARDWAREGAIN),		\
}

static const struct iio_chan_spec hmc425a_channels[] = {
	HMC425A_CHAN(0),
};

/* Match table for of_platform binding */
static const struct of_device_id hmc425a_of_match[] = {
	{ .compatible = "adi,hmc425a", .data = (void *)ID_HMC425A },
	{},
};
MODULE_DEVICE_TABLE(of, hmc425a_of_match);

static void hmc425a_reg_disable(void *data)
{
	struct hmc425a_state *st = data;

	regulator_disable(st->reg);
}

static struct hmc425a_chip_info hmc425a_chip_info_tbl[] = {
	[ID_HMC425A] = {
		.name = "hmc425a",
		.channels = hmc425a_channels,
		.num_channels = ARRAY_SIZE(hmc425a_channels),
		.num_gpios = 6,
		.gain_min = -31500,
		.gain_max = 0,
		.default_gain = -0x40, /* set default gain -31.5db*/
	},
};

static int hmc425a_probe(struct platform_device *pdev)
{
	struct iio_dev *indio_dev;
	struct hmc425a_state *st;
	int ret;

	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*st));
	if (!indio_dev)
		return -ENOMEM;

	st = iio_priv(indio_dev);
	st->type = (uintptr_t)of_device_get_match_data(&pdev->dev);

	st->chip_info = &hmc425a_chip_info_tbl[st->type];
	indio_dev->num_channels = st->chip_info->num_channels;
	indio_dev->channels = st->chip_info->channels;
	indio_dev->name = st->chip_info->name;
	st->gain = st->chip_info->default_gain;

	st->gpios = devm_gpiod_get_array(&pdev->dev, "ctrl", GPIOD_OUT_LOW);
	if (IS_ERR(st->gpios))
		return dev_err_probe(&pdev->dev, PTR_ERR(st->gpios),
				     "failed to get gpios\n");

	if (st->gpios->ndescs != st->chip_info->num_gpios) {
		dev_err(&pdev->dev, "%d GPIOs needed to operate\n",
			st->chip_info->num_gpios);
		return -ENODEV;
	}

	st->reg = devm_regulator_get(&pdev->dev, "vcc-supply");
	if (IS_ERR(st->reg))
		return PTR_ERR(st->reg);

	ret = regulator_enable(st->reg);
	if (ret)
		return ret;
	ret = devm_add_action_or_reset(&pdev->dev, hmc425a_reg_disable, st);
	if (ret)
		return ret;

	mutex_init(&st->lock);

	indio_dev->info = &hmc425a_info;
	indio_dev->modes = INDIO_DIRECT_MODE;

	return devm_iio_device_register(&pdev->dev, indio_dev);
}

static struct platform_driver hmc425a_driver = {
	.driver = {
		.name = KBUILD_MODNAME,
		.of_match_table = hmc425a_of_match,
	},
	.probe = hmc425a_probe,
};
module_platform_driver(hmc425a_driver);

MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
MODULE_DESCRIPTION("Analog Devices HMC425A and similar GPIO control Gain Amplifiers");
MODULE_LICENSE("GPL v2");