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
22 enum hmc425a_type {
23 ID_HMC425A,
24 };
25
26 struct 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
36 struct 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
hmc425a_write(struct iio_dev * indio_dev,u32 value)44 static 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
hmc425a_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long m)56 static 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
hmc425a_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)88 static 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
hmc425a_write_raw_get_fmt(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,long mask)126 static 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
138 static 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
153 static const struct iio_chan_spec hmc425a_channels[] = {
154 HMC425A_CHAN(0),
155 };
156
157 /* Match table for of_platform binding */
158 static const struct of_device_id hmc425a_of_match[] = {
159 { .compatible = "adi,hmc425a", .data = (void *)ID_HMC425A },
160 {},
161 };
162 MODULE_DEVICE_TABLE(of, hmc425a_of_match);
163
164 static 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
hmc425a_probe(struct platform_device * pdev)176 static 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
218 static struct platform_driver hmc425a_driver = {
219 .driver = {
220 .name = KBUILD_MODNAME,
221 .of_match_table = hmc425a_of_match,
222 },
223 .probe = hmc425a_probe,
224 };
225 module_platform_driver(hmc425a_driver);
226
227 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
228 MODULE_DESCRIPTION("Analog Devices HMC425A and similar GPIO control Gain Amplifiers");
229 MODULE_LICENSE("GPL v2");
230
