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/bitops.h>
9 #include <linux/device.h>
10 #include <linux/err.h>
11 #include <linux/gpio/consumer.h>
12 #include <linux/iio/iio.h>
13 #include <linux/iio/sysfs.h>
14 #include <linux/kernel.h>
15 #include <linux/mod_devicetable.h>
16 #include <linux/module.h>
17 #include <linux/platform_device.h>
18 #include <linux/property.h>
19 #include <linux/slab.h>
20 #include <linux/regulator/consumer.h>
21 #include <linux/sysfs.h>
22
23 enum hmc425a_type {
24 ID_HMC425A,
25 ID_HMC540S,
26 ID_ADRF5740
27 };
28
29 struct hmc425a_chip_info {
30 const char *name;
31 const struct iio_chan_spec *channels;
32 unsigned int num_channels;
33 unsigned int num_gpios;
34 int gain_min;
35 int gain_max;
36 int default_gain;
37 };
38
39 struct hmc425a_state {
40 struct mutex lock; /* protect sensor state */
41 struct hmc425a_chip_info *chip_info;
42 struct gpio_descs *gpios;
43 enum hmc425a_type type;
44 u32 gain;
45 };
46
hmc425a_write(struct iio_dev * indio_dev,u32 value)47 static int hmc425a_write(struct iio_dev *indio_dev, u32 value)
48 {
49 struct hmc425a_state *st = iio_priv(indio_dev);
50 DECLARE_BITMAP(values, BITS_PER_TYPE(value));
51
52 values[0] = value;
53
54 gpiod_set_array_value_cansleep(st->gpios->ndescs, st->gpios->desc,
55 NULL, values);
56 return 0;
57 }
58
hmc425a_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long m)59 static int hmc425a_read_raw(struct iio_dev *indio_dev,
60 struct iio_chan_spec const *chan, int *val,
61 int *val2, long m)
62 {
63 struct hmc425a_state *st = iio_priv(indio_dev);
64 int code, gain = 0;
65 int ret;
66
67 mutex_lock(&st->lock);
68 switch (m) {
69 case IIO_CHAN_INFO_HARDWAREGAIN:
70 code = st->gain;
71
72 switch (st->type) {
73 case ID_HMC425A:
74 gain = ~code * -500;
75 break;
76 case ID_HMC540S:
77 gain = ~code * -1000;
78 break;
79 case ID_ADRF5740:
80 code = code & BIT(3) ? code & ~BIT(2) : code;
81 gain = code * -2000;
82 break;
83 }
84
85 *val = gain / 1000;
86 *val2 = (gain % 1000) * 1000;
87
88 ret = IIO_VAL_INT_PLUS_MICRO_DB;
89 break;
90 default:
91 ret = -EINVAL;
92 }
93 mutex_unlock(&st->lock);
94
95 return ret;
96 };
97
hmc425a_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)98 static int hmc425a_write_raw(struct iio_dev *indio_dev,
99 struct iio_chan_spec const *chan, int val,
100 int val2, long mask)
101 {
102 struct hmc425a_state *st = iio_priv(indio_dev);
103 struct hmc425a_chip_info *inf = st->chip_info;
104 int code = 0, gain;
105 int ret;
106
107 if (val < 0)
108 gain = (val * 1000) - (val2 / 1000);
109 else
110 gain = (val * 1000) + (val2 / 1000);
111
112 if (gain > inf->gain_max || gain < inf->gain_min)
113 return -EINVAL;
114
115 switch (st->type) {
116 case ID_HMC425A:
117 code = ~((abs(gain) / 500) & 0x3F);
118 break;
119 case ID_HMC540S:
120 code = ~((abs(gain) / 1000) & 0xF);
121 break;
122 case ID_ADRF5740:
123 code = (abs(gain) / 2000) & 0xF;
124 code = code & BIT(3) ? code | BIT(2) : code;
125 break;
126 }
127
128 mutex_lock(&st->lock);
129 switch (mask) {
130 case IIO_CHAN_INFO_HARDWAREGAIN:
131 st->gain = code;
132
133 ret = hmc425a_write(indio_dev, st->gain);
134 break;
135 default:
136 ret = -EINVAL;
137 }
138 mutex_unlock(&st->lock);
139
140 return ret;
141 }
142
hmc425a_write_raw_get_fmt(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,long mask)143 static int hmc425a_write_raw_get_fmt(struct iio_dev *indio_dev,
144 struct iio_chan_spec const *chan,
145 long mask)
146 {
147 switch (mask) {
148 case IIO_CHAN_INFO_HARDWAREGAIN:
149 return IIO_VAL_INT_PLUS_MICRO_DB;
150 default:
151 return -EINVAL;
152 }
153 }
154
155 static const struct iio_info hmc425a_info = {
156 .read_raw = &hmc425a_read_raw,
157 .write_raw = &hmc425a_write_raw,
158 .write_raw_get_fmt = &hmc425a_write_raw_get_fmt,
159 };
160
161 #define HMC425A_CHAN(_channel) \
162 { \
163 .type = IIO_VOLTAGE, \
164 .output = 1, \
165 .indexed = 1, \
166 .channel = _channel, \
167 .info_mask_separate = BIT(IIO_CHAN_INFO_HARDWAREGAIN), \
168 }
169
170 static const struct iio_chan_spec hmc425a_channels[] = {
171 HMC425A_CHAN(0),
172 };
173
174 /* Match table for of_platform binding */
175 static const struct of_device_id hmc425a_of_match[] = {
176 { .compatible = "adi,hmc425a", .data = (void *)ID_HMC425A },
177 { .compatible = "adi,hmc540s", .data = (void *)ID_HMC540S },
178 { .compatible = "adi,adrf5740", .data = (void *)ID_ADRF5740 },
179 {},
180 };
181 MODULE_DEVICE_TABLE(of, hmc425a_of_match);
182
183 static struct hmc425a_chip_info hmc425a_chip_info_tbl[] = {
184 [ID_HMC425A] = {
185 .name = "hmc425a",
186 .channels = hmc425a_channels,
187 .num_channels = ARRAY_SIZE(hmc425a_channels),
188 .num_gpios = 6,
189 .gain_min = -31500,
190 .gain_max = 0,
191 .default_gain = -0x40, /* set default gain -31.5db*/
192 },
193 [ID_HMC540S] = {
194 .name = "hmc540s",
195 .channels = hmc425a_channels,
196 .num_channels = ARRAY_SIZE(hmc425a_channels),
197 .num_gpios = 4,
198 .gain_min = -15000,
199 .gain_max = 0,
200 .default_gain = -0x10, /* set default gain -15.0db*/
201 },
202 [ID_ADRF5740] = {
203 .name = "adrf5740",
204 .channels = hmc425a_channels,
205 .num_channels = ARRAY_SIZE(hmc425a_channels),
206 .num_gpios = 4,
207 .gain_min = -22000,
208 .gain_max = 0,
209 .default_gain = 0xF, /* set default gain -22.0db*/
210 },
211 };
212
hmc425a_probe(struct platform_device * pdev)213 static int hmc425a_probe(struct platform_device *pdev)
214 {
215 struct iio_dev *indio_dev;
216 struct hmc425a_state *st;
217 int ret;
218
219 indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*st));
220 if (!indio_dev)
221 return -ENOMEM;
222
223 st = iio_priv(indio_dev);
224 st->type = (uintptr_t)device_get_match_data(&pdev->dev);
225
226 st->chip_info = &hmc425a_chip_info_tbl[st->type];
227 indio_dev->num_channels = st->chip_info->num_channels;
228 indio_dev->channels = st->chip_info->channels;
229 indio_dev->name = st->chip_info->name;
230 st->gain = st->chip_info->default_gain;
231
232 st->gpios = devm_gpiod_get_array(&pdev->dev, "ctrl", GPIOD_OUT_LOW);
233 if (IS_ERR(st->gpios))
234 return dev_err_probe(&pdev->dev, PTR_ERR(st->gpios),
235 "failed to get gpios\n");
236
237 if (st->gpios->ndescs != st->chip_info->num_gpios) {
238 dev_err(&pdev->dev, "%d GPIOs needed to operate\n",
239 st->chip_info->num_gpios);
240 return -ENODEV;
241 }
242
243 ret = devm_regulator_get_enable(&pdev->dev, "vcc-supply");
244 if (ret)
245 return ret;
246
247 mutex_init(&st->lock);
248
249 indio_dev->info = &hmc425a_info;
250 indio_dev->modes = INDIO_DIRECT_MODE;
251
252 /* Set default gain */
253 hmc425a_write(indio_dev, st->gain);
254
255 return devm_iio_device_register(&pdev->dev, indio_dev);
256 }
257
258 static struct platform_driver hmc425a_driver = {
259 .driver = {
260 .name = KBUILD_MODNAME,
261 .of_match_table = hmc425a_of_match,
262 },
263 .probe = hmc425a_probe,
264 };
265 module_platform_driver(hmc425a_driver);
266
267 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
268 MODULE_DESCRIPTION("Analog Devices HMC425A and similar GPIO control Gain Amplifiers");
269 MODULE_LICENSE("GPL v2");
270