1// SPDX-License-Identifier: GPL-2.0
2/*
3 * HMC425A and similar Gain Amplifiers
4 *
5 * Copyright 2020 Analog Devices Inc.
6 */
7
8#include <linux/device.h>
9#include <linux/err.h>
10#include <linux/gpio/consumer.h>
11#include <linux/iio/iio.h>
12#include <linux/iio/sysfs.h>
13#include <linux/kernel.h>
14#include <linux/mod_devicetable.h>
15#include <linux/module.h>
16#include <linux/platform_device.h>
17#include <linux/property.h>
18#include <linux/slab.h>
19#include <linux/regulator/consumer.h>
20#include <linux/sysfs.h>
21
22enum hmc425a_type {
23	ID_HMC425A,
24};
25
26struct hmc425a_chip_info {
27	const char			*name;
28	const struct iio_chan_spec	*channels;
29	unsigned int			num_channels;
30	unsigned int			num_gpios;
31	int				gain_min;
32	int				gain_max;
33	int				default_gain;
34};
35
36struct hmc425a_state {
37	struct	mutex lock; /* protect sensor state */
38	struct	hmc425a_chip_info *chip_info;
39	struct	gpio_descs *gpios;
40	enum	hmc425a_type type;
41	u32	gain;
42};
43
44static int hmc425a_write(struct iio_dev *indio_dev, u32 value)
45{
46	struct hmc425a_state *st = iio_priv(indio_dev);
47	DECLARE_BITMAP(values, BITS_PER_TYPE(value));
48
49	values[0] = value;
50
51	gpiod_set_array_value_cansleep(st->gpios->ndescs, st->gpios->desc,
52				       NULL, values);
53	return 0;
54}
55
56static int hmc425a_read_raw(struct iio_dev *indio_dev,
57			    struct iio_chan_spec const *chan, int *val,
58			    int *val2, long m)
59{
60	struct hmc425a_state *st = iio_priv(indio_dev);
61	int code, gain = 0;
62	int ret;
63
64	mutex_lock(&st->lock);
65	switch (m) {
66	case IIO_CHAN_INFO_HARDWAREGAIN:
67		code = st->gain;
68
69		switch (st->type) {
70		case ID_HMC425A:
71			gain = ~code * -500;
72			break;
73		}
74
75		*val = gain / 1000;
76		*val2 = (gain % 1000) * 1000;
77
78		ret = IIO_VAL_INT_PLUS_MICRO_DB;
79		break;
80	default:
81		ret = -EINVAL;
82	}
83	mutex_unlock(&st->lock);
84
85	return ret;
86};
87
88static int hmc425a_write_raw(struct iio_dev *indio_dev,
89			     struct iio_chan_spec const *chan, int val,
90			     int val2, long mask)
91{
92	struct hmc425a_state *st = iio_priv(indio_dev);
93	struct hmc425a_chip_info *inf = st->chip_info;
94	int code = 0, gain;
95	int ret;
96
97	if (val < 0)
98		gain = (val * 1000) - (val2 / 1000);
99	else
100		gain = (val * 1000) + (val2 / 1000);
101
102	if (gain > inf->gain_max || gain < inf->gain_min)
103		return -EINVAL;
104
105	switch (st->type) {
106	case ID_HMC425A:
107		code = ~((abs(gain) / 500) & 0x3F);
108		break;
109	}
110
111	mutex_lock(&st->lock);
112	switch (mask) {
113	case IIO_CHAN_INFO_HARDWAREGAIN:
114		st->gain = code;
115
116		ret = hmc425a_write(indio_dev, st->gain);
117		break;
118	default:
119		ret = -EINVAL;
120	}
121	mutex_unlock(&st->lock);
122
123	return ret;
124}
125
126static int hmc425a_write_raw_get_fmt(struct iio_dev *indio_dev,
127				     struct iio_chan_spec const *chan,
128				     long mask)
129{
130	switch (mask) {
131	case IIO_CHAN_INFO_HARDWAREGAIN:
132		return IIO_VAL_INT_PLUS_MICRO_DB;
133	default:
134		return -EINVAL;
135	}
136}
137
138static const struct iio_info hmc425a_info = {
139	.read_raw = &hmc425a_read_raw,
140	.write_raw = &hmc425a_write_raw,
141	.write_raw_get_fmt = &hmc425a_write_raw_get_fmt,
142};
143
144#define HMC425A_CHAN(_channel)						\
145{									\
146	.type = IIO_VOLTAGE,						\
147	.output = 1,							\
148	.indexed = 1,							\
149	.channel = _channel,						\
150	.info_mask_separate = BIT(IIO_CHAN_INFO_HARDWAREGAIN),		\
151}
152
153static const struct iio_chan_spec hmc425a_channels[] = {
154	HMC425A_CHAN(0),
155};
156
157/* Match table for of_platform binding */
158static const struct of_device_id hmc425a_of_match[] = {
159	{ .compatible = "adi,hmc425a", .data = (void *)ID_HMC425A },
160	{},
161};
162MODULE_DEVICE_TABLE(of, hmc425a_of_match);
163
164static struct hmc425a_chip_info hmc425a_chip_info_tbl[] = {
165	[ID_HMC425A] = {
166		.name = "hmc425a",
167		.channels = hmc425a_channels,
168		.num_channels = ARRAY_SIZE(hmc425a_channels),
169		.num_gpios = 6,
170		.gain_min = -31500,
171		.gain_max = 0,
172		.default_gain = -0x40, /* set default gain -31.5db*/
173	},
174};
175
176static int hmc425a_probe(struct platform_device *pdev)
177{
178	struct iio_dev *indio_dev;
179	struct hmc425a_state *st;
180	int ret;
181
182	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*st));
183	if (!indio_dev)
184		return -ENOMEM;
185
186	st = iio_priv(indio_dev);
187	st->type = (uintptr_t)device_get_match_data(&pdev->dev);
188
189	st->chip_info = &hmc425a_chip_info_tbl[st->type];
190	indio_dev->num_channels = st->chip_info->num_channels;
191	indio_dev->channels = st->chip_info->channels;
192	indio_dev->name = st->chip_info->name;
193	st->gain = st->chip_info->default_gain;
194
195	st->gpios = devm_gpiod_get_array(&pdev->dev, "ctrl", GPIOD_OUT_LOW);
196	if (IS_ERR(st->gpios))
197		return dev_err_probe(&pdev->dev, PTR_ERR(st->gpios),
198				     "failed to get gpios\n");
199
200	if (st->gpios->ndescs != st->chip_info->num_gpios) {
201		dev_err(&pdev->dev, "%d GPIOs needed to operate\n",
202			st->chip_info->num_gpios);
203		return -ENODEV;
204	}
205
206	ret = devm_regulator_get_enable(&pdev->dev, "vcc-supply");
207	if (ret)
208		return ret;
209
210	mutex_init(&st->lock);
211
212	indio_dev->info = &hmc425a_info;
213	indio_dev->modes = INDIO_DIRECT_MODE;
214
215	return devm_iio_device_register(&pdev->dev, indio_dev);
216}
217
218static struct platform_driver hmc425a_driver = {
219	.driver = {
220		.name = KBUILD_MODNAME,
221		.of_match_table = hmc425a_of_match,
222	},
223	.probe = hmc425a_probe,
224};
225module_platform_driver(hmc425a_driver);
226
227MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
228MODULE_DESCRIPTION("Analog Devices HMC425A and similar GPIO control Gain Amplifiers");
229MODULE_LICENSE("GPL v2");
230