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/module.h>
15#include <linux/of_device.h>
16#include <linux/of_platform.h>
17#include <linux/platform_device.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	regulator *reg;
38	struct	mutex lock; /* protect sensor state */
39	struct	hmc425a_chip_info *chip_info;
40	struct	gpio_descs *gpios;
41	enum	hmc425a_type type;
42	u32	gain;
43};
44
45static int hmc425a_write(struct iio_dev *indio_dev, u32 value)
46{
47	struct hmc425a_state *st = iio_priv(indio_dev);
48	DECLARE_BITMAP(values, BITS_PER_TYPE(value));
49
50	values[0] = value;
51
52	gpiod_set_array_value_cansleep(st->gpios->ndescs, st->gpios->desc,
53				       NULL, values);
54	return 0;
55}
56
57static int hmc425a_read_raw(struct iio_dev *indio_dev,
58			    struct iio_chan_spec const *chan, int *val,
59			    int *val2, long m)
60{
61	struct hmc425a_state *st = iio_priv(indio_dev);
62	int code, gain = 0;
63	int ret;
64
65	mutex_lock(&st->lock);
66	switch (m) {
67	case IIO_CHAN_INFO_HARDWAREGAIN:
68		code = st->gain;
69
70		switch (st->type) {
71		case ID_HMC425A:
72			gain = ~code * -500;
73			break;
74		}
75
76		*val = gain / 1000;
77		*val2 = (gain % 1000) * 1000;
78
79		ret = IIO_VAL_INT_PLUS_MICRO_DB;
80		break;
81	default:
82		ret = -EINVAL;
83	}
84	mutex_unlock(&st->lock);
85
86	return ret;
87};
88
89static int hmc425a_write_raw(struct iio_dev *indio_dev,
90			     struct iio_chan_spec const *chan, int val,
91			     int val2, long mask)
92{
93	struct hmc425a_state *st = iio_priv(indio_dev);
94	struct hmc425a_chip_info *inf = st->chip_info;
95	int code = 0, gain;
96	int ret;
97
98	if (val < 0)
99		gain = (val * 1000) - (val2 / 1000);
100	else
101		gain = (val * 1000) + (val2 / 1000);
102
103	if (gain > inf->gain_max || gain < inf->gain_min)
104		return -EINVAL;
105
106	switch (st->type) {
107	case ID_HMC425A:
108		code = ~((abs(gain) / 500) & 0x3F);
109		break;
110	}
111
112	mutex_lock(&st->lock);
113	switch (mask) {
114	case IIO_CHAN_INFO_HARDWAREGAIN:
115		st->gain = code;
116
117		ret = hmc425a_write(indio_dev, st->gain);
118		break;
119	default:
120		ret = -EINVAL;
121	}
122	mutex_unlock(&st->lock);
123
124	return ret;
125}
126
127static int hmc425a_write_raw_get_fmt(struct iio_dev *indio_dev,
128				     struct iio_chan_spec const *chan,
129				     long mask)
130{
131	switch (mask) {
132	case IIO_CHAN_INFO_HARDWAREGAIN:
133		return IIO_VAL_INT_PLUS_MICRO_DB;
134	default:
135		return -EINVAL;
136	}
137}
138
139static const struct iio_info hmc425a_info = {
140	.read_raw = &hmc425a_read_raw,
141	.write_raw = &hmc425a_write_raw,
142	.write_raw_get_fmt = &hmc425a_write_raw_get_fmt,
143};
144
145#define HMC425A_CHAN(_channel)						\
146{									\
147	.type = IIO_VOLTAGE,						\
148	.output = 1,							\
149	.indexed = 1,							\
150	.channel = _channel,						\
151	.info_mask_separate = BIT(IIO_CHAN_INFO_HARDWAREGAIN),		\
152}
153
154static const struct iio_chan_spec hmc425a_channels[] = {
155	HMC425A_CHAN(0),
156};
157
158/* Match table for of_platform binding */
159static const struct of_device_id hmc425a_of_match[] = {
160	{ .compatible = "adi,hmc425a", .data = (void *)ID_HMC425A },
161	{},
162};
163MODULE_DEVICE_TABLE(of, hmc425a_of_match);
164
165static void hmc425a_reg_disable(void *data)
166{
167	struct hmc425a_state *st = data;
168
169	regulator_disable(st->reg);
170}
171
172static struct hmc425a_chip_info hmc425a_chip_info_tbl[] = {
173	[ID_HMC425A] = {
174		.name = "hmc425a",
175		.channels = hmc425a_channels,
176		.num_channels = ARRAY_SIZE(hmc425a_channels),
177		.num_gpios = 6,
178		.gain_min = -31500,
179		.gain_max = 0,
180		.default_gain = -0x40, /* set default gain -31.5db*/
181	},
182};
183
184static int hmc425a_probe(struct platform_device *pdev)
185{
186	struct iio_dev *indio_dev;
187	struct hmc425a_state *st;
188	int ret;
189
190	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*st));
191	if (!indio_dev)
192		return -ENOMEM;
193
194	st = iio_priv(indio_dev);
195	st->type = (enum hmc425a_type)of_device_get_match_data(&pdev->dev);
196
197	st->chip_info = &hmc425a_chip_info_tbl[st->type];
198	indio_dev->num_channels = st->chip_info->num_channels;
199	indio_dev->channels = st->chip_info->channels;
200	indio_dev->name = st->chip_info->name;
201	st->gain = st->chip_info->default_gain;
202
203	st->gpios = devm_gpiod_get_array(&pdev->dev, "ctrl", GPIOD_OUT_LOW);
204	if (IS_ERR(st->gpios))
205		return dev_err_probe(&pdev->dev, PTR_ERR(st->gpios),
206				     "failed to get gpios\n");
207
208	if (st->gpios->ndescs != st->chip_info->num_gpios) {
209		dev_err(&pdev->dev, "%d GPIOs needed to operate\n",
210			st->chip_info->num_gpios);
211		return -ENODEV;
212	}
213
214	st->reg = devm_regulator_get(&pdev->dev, "vcc-supply");
215	if (IS_ERR(st->reg))
216		return PTR_ERR(st->reg);
217
218	ret = regulator_enable(st->reg);
219	if (ret)
220		return ret;
221	ret = devm_add_action_or_reset(&pdev->dev, hmc425a_reg_disable, st);
222	if (ret)
223		return ret;
224
225	mutex_init(&st->lock);
226
227	indio_dev->info = &hmc425a_info;
228	indio_dev->modes = INDIO_DIRECT_MODE;
229
230	return devm_iio_device_register(&pdev->dev, indio_dev);
231}
232
233static struct platform_driver hmc425a_driver = {
234	.driver = {
235		.name = KBUILD_MODNAME,
236		.of_match_table = hmc425a_of_match,
237	},
238	.probe = hmc425a_probe,
239};
240module_platform_driver(hmc425a_driver);
241
242MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
243MODULE_DESCRIPTION("Analog Devices HMC425A and similar GPIO control Gain Amplifiers");
244MODULE_LICENSE("GPL v2");
245