1733e0fedSLiam Beguin // SPDX-License-Identifier: GPL-2.0
2733e0fedSLiam Beguin /*
3733e0fedSLiam Beguin * The LTC2309 is an 8-Channel, 12-Bit SAR ADC with an I2C Interface.
4733e0fedSLiam Beguin *
5733e0fedSLiam Beguin * Datasheet:
6733e0fedSLiam Beguin * https://www.analog.com/media/en/technical-documentation/data-sheets/2309fd.pdf
7733e0fedSLiam Beguin *
8733e0fedSLiam Beguin * Copyright (c) 2023, Liam Beguin <liambeguin@gmail.com>
9733e0fedSLiam Beguin */
10733e0fedSLiam Beguin #include <linux/bitfield.h>
11733e0fedSLiam Beguin #include <linux/i2c.h>
12733e0fedSLiam Beguin #include <linux/iio/iio.h>
13733e0fedSLiam Beguin #include <linux/kernel.h>
14733e0fedSLiam Beguin #include <linux/module.h>
15733e0fedSLiam Beguin #include <linux/mutex.h>
16733e0fedSLiam Beguin #include <linux/regulator/consumer.h>
17733e0fedSLiam Beguin
18733e0fedSLiam Beguin #define LTC2309_ADC_RESOLUTION 12
19890582c2SDavid Lechner #define LTC2309_INTERNAL_REF_MV 4096
20733e0fedSLiam Beguin
21733e0fedSLiam Beguin #define LTC2309_DIN_CH_MASK GENMASK(7, 4)
22733e0fedSLiam Beguin #define LTC2309_DIN_SDN BIT(7)
23733e0fedSLiam Beguin #define LTC2309_DIN_OSN BIT(6)
24733e0fedSLiam Beguin #define LTC2309_DIN_S1 BIT(5)
25733e0fedSLiam Beguin #define LTC2309_DIN_S0 BIT(4)
26733e0fedSLiam Beguin #define LTC2309_DIN_UNI BIT(3)
27733e0fedSLiam Beguin #define LTC2309_DIN_SLEEP BIT(2)
28733e0fedSLiam Beguin
29733e0fedSLiam Beguin /**
30733e0fedSLiam Beguin * struct ltc2309 - internal device data structure
31733e0fedSLiam Beguin * @dev: Device reference
32733e0fedSLiam Beguin * @client: I2C reference
33733e0fedSLiam Beguin * @lock: Lock to serialize data access
34733e0fedSLiam Beguin * @vref_mv: Internal voltage reference
35733e0fedSLiam Beguin */
36733e0fedSLiam Beguin struct ltc2309 {
37733e0fedSLiam Beguin struct device *dev;
38733e0fedSLiam Beguin struct i2c_client *client;
39733e0fedSLiam Beguin struct mutex lock; /* serialize data access */
40733e0fedSLiam Beguin int vref_mv;
41733e0fedSLiam Beguin };
42733e0fedSLiam Beguin
43733e0fedSLiam Beguin /* Order matches expected channel address, See datasheet Table 1. */
44733e0fedSLiam Beguin enum ltc2309_channels {
45733e0fedSLiam Beguin LTC2309_CH0_CH1 = 0,
46733e0fedSLiam Beguin LTC2309_CH2_CH3,
47733e0fedSLiam Beguin LTC2309_CH4_CH5,
48733e0fedSLiam Beguin LTC2309_CH6_CH7,
49733e0fedSLiam Beguin LTC2309_CH1_CH0,
50733e0fedSLiam Beguin LTC2309_CH3_CH2,
51733e0fedSLiam Beguin LTC2309_CH5_CH4,
52733e0fedSLiam Beguin LTC2309_CH7_CH6,
53733e0fedSLiam Beguin LTC2309_CH0,
54733e0fedSLiam Beguin LTC2309_CH2,
55733e0fedSLiam Beguin LTC2309_CH4,
56733e0fedSLiam Beguin LTC2309_CH6,
57733e0fedSLiam Beguin LTC2309_CH1,
58733e0fedSLiam Beguin LTC2309_CH3,
59733e0fedSLiam Beguin LTC2309_CH5,
60733e0fedSLiam Beguin LTC2309_CH7,
61733e0fedSLiam Beguin };
62733e0fedSLiam Beguin
63733e0fedSLiam Beguin #define LTC2309_CHAN(_chan, _addr) { \
64733e0fedSLiam Beguin .type = IIO_VOLTAGE, \
65733e0fedSLiam Beguin .indexed = 1, \
66733e0fedSLiam Beguin .address = _addr, \
67733e0fedSLiam Beguin .channel = _chan, \
68733e0fedSLiam Beguin .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
69733e0fedSLiam Beguin .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
70733e0fedSLiam Beguin }
71733e0fedSLiam Beguin
72733e0fedSLiam Beguin #define LTC2309_DIFF_CHAN(_chan, _chan2, _addr) { \
73733e0fedSLiam Beguin .type = IIO_VOLTAGE, \
74733e0fedSLiam Beguin .differential = 1, \
75733e0fedSLiam Beguin .indexed = 1, \
76733e0fedSLiam Beguin .address = _addr, \
77733e0fedSLiam Beguin .channel = _chan, \
78733e0fedSLiam Beguin .channel2 = _chan2, \
79733e0fedSLiam Beguin .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
80733e0fedSLiam Beguin .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
81733e0fedSLiam Beguin }
82733e0fedSLiam Beguin
83733e0fedSLiam Beguin static const struct iio_chan_spec ltc2309_channels[] = {
84733e0fedSLiam Beguin LTC2309_CHAN(0, LTC2309_CH0),
85733e0fedSLiam Beguin LTC2309_CHAN(1, LTC2309_CH1),
86733e0fedSLiam Beguin LTC2309_CHAN(2, LTC2309_CH2),
87733e0fedSLiam Beguin LTC2309_CHAN(3, LTC2309_CH3),
88733e0fedSLiam Beguin LTC2309_CHAN(4, LTC2309_CH4),
89733e0fedSLiam Beguin LTC2309_CHAN(5, LTC2309_CH5),
90733e0fedSLiam Beguin LTC2309_CHAN(6, LTC2309_CH6),
91733e0fedSLiam Beguin LTC2309_CHAN(7, LTC2309_CH7),
92733e0fedSLiam Beguin LTC2309_DIFF_CHAN(0, 1, LTC2309_CH0_CH1),
93733e0fedSLiam Beguin LTC2309_DIFF_CHAN(2, 3, LTC2309_CH2_CH3),
94733e0fedSLiam Beguin LTC2309_DIFF_CHAN(4, 5, LTC2309_CH4_CH5),
95733e0fedSLiam Beguin LTC2309_DIFF_CHAN(6, 7, LTC2309_CH6_CH7),
96733e0fedSLiam Beguin LTC2309_DIFF_CHAN(1, 0, LTC2309_CH1_CH0),
97733e0fedSLiam Beguin LTC2309_DIFF_CHAN(3, 2, LTC2309_CH3_CH2),
98733e0fedSLiam Beguin LTC2309_DIFF_CHAN(5, 4, LTC2309_CH5_CH4),
99733e0fedSLiam Beguin LTC2309_DIFF_CHAN(7, 6, LTC2309_CH7_CH6),
100733e0fedSLiam Beguin };
101733e0fedSLiam Beguin
ltc2309_read_raw_channel(struct ltc2309 * ltc2309,unsigned long address,int * val)102733e0fedSLiam Beguin static int ltc2309_read_raw_channel(struct ltc2309 *ltc2309,
103733e0fedSLiam Beguin unsigned long address, int *val)
104733e0fedSLiam Beguin {
105733e0fedSLiam Beguin int ret;
106*96419729SJonathan Cameron __be16 buf;
107733e0fedSLiam Beguin u8 din;
108733e0fedSLiam Beguin
109733e0fedSLiam Beguin din = FIELD_PREP(LTC2309_DIN_CH_MASK, address & 0x0f) |
110733e0fedSLiam Beguin FIELD_PREP(LTC2309_DIN_UNI, 1) |
111733e0fedSLiam Beguin FIELD_PREP(LTC2309_DIN_SLEEP, 0);
112733e0fedSLiam Beguin
113733e0fedSLiam Beguin ret = i2c_smbus_write_byte(ltc2309->client, din);
114733e0fedSLiam Beguin if (ret < 0) {
115733e0fedSLiam Beguin dev_err(ltc2309->dev, "i2c command failed: %pe\n",
116733e0fedSLiam Beguin ERR_PTR(ret));
117733e0fedSLiam Beguin return ret;
118733e0fedSLiam Beguin }
119733e0fedSLiam Beguin
120733e0fedSLiam Beguin ret = i2c_master_recv(ltc2309->client, (char *)&buf, 2);
121733e0fedSLiam Beguin if (ret < 0) {
122733e0fedSLiam Beguin dev_err(ltc2309->dev, "i2c read failed: %pe\n", ERR_PTR(ret));
123733e0fedSLiam Beguin return ret;
124733e0fedSLiam Beguin }
125733e0fedSLiam Beguin
126733e0fedSLiam Beguin *val = be16_to_cpu(buf) >> 4;
127733e0fedSLiam Beguin
128733e0fedSLiam Beguin return ret;
129733e0fedSLiam Beguin }
130733e0fedSLiam Beguin
ltc2309_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)131733e0fedSLiam Beguin static int ltc2309_read_raw(struct iio_dev *indio_dev,
132733e0fedSLiam Beguin struct iio_chan_spec const *chan, int *val,
133733e0fedSLiam Beguin int *val2, long mask)
134733e0fedSLiam Beguin {
135733e0fedSLiam Beguin struct ltc2309 *ltc2309 = iio_priv(indio_dev);
136733e0fedSLiam Beguin int ret;
137733e0fedSLiam Beguin
138733e0fedSLiam Beguin switch (mask) {
139733e0fedSLiam Beguin case IIO_CHAN_INFO_RAW:
140733e0fedSLiam Beguin mutex_lock(<c2309->lock);
141733e0fedSLiam Beguin ret = ltc2309_read_raw_channel(ltc2309, chan->address, val);
142733e0fedSLiam Beguin mutex_unlock(<c2309->lock);
143733e0fedSLiam Beguin if (ret < 0)
144733e0fedSLiam Beguin return -EINVAL;
145733e0fedSLiam Beguin return IIO_VAL_INT;
146733e0fedSLiam Beguin case IIO_CHAN_INFO_SCALE:
147733e0fedSLiam Beguin *val = ltc2309->vref_mv;
148733e0fedSLiam Beguin *val2 = LTC2309_ADC_RESOLUTION;
149733e0fedSLiam Beguin return IIO_VAL_FRACTIONAL_LOG2;
150733e0fedSLiam Beguin default:
151733e0fedSLiam Beguin return -EINVAL;
152733e0fedSLiam Beguin }
153733e0fedSLiam Beguin }
154733e0fedSLiam Beguin
155733e0fedSLiam Beguin static const struct iio_info ltc2309_info = {
156733e0fedSLiam Beguin .read_raw = ltc2309_read_raw,
157733e0fedSLiam Beguin };
158733e0fedSLiam Beguin
ltc2309_probe(struct i2c_client * client)159733e0fedSLiam Beguin static int ltc2309_probe(struct i2c_client *client)
160733e0fedSLiam Beguin {
161733e0fedSLiam Beguin struct iio_dev *indio_dev;
162733e0fedSLiam Beguin struct ltc2309 *ltc2309;
163733e0fedSLiam Beguin int ret;
164733e0fedSLiam Beguin
165733e0fedSLiam Beguin indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*ltc2309));
166733e0fedSLiam Beguin if (!indio_dev)
167733e0fedSLiam Beguin return -ENOMEM;
168733e0fedSLiam Beguin
169733e0fedSLiam Beguin ltc2309 = iio_priv(indio_dev);
170733e0fedSLiam Beguin ltc2309->dev = &indio_dev->dev;
171733e0fedSLiam Beguin ltc2309->client = client;
172733e0fedSLiam Beguin
173733e0fedSLiam Beguin indio_dev->name = "ltc2309";
174733e0fedSLiam Beguin indio_dev->modes = INDIO_DIRECT_MODE;
175733e0fedSLiam Beguin indio_dev->channels = ltc2309_channels;
176733e0fedSLiam Beguin indio_dev->num_channels = ARRAY_SIZE(ltc2309_channels);
177733e0fedSLiam Beguin indio_dev->info = <c2309_info;
178733e0fedSLiam Beguin
179890582c2SDavid Lechner ret = devm_regulator_get_enable_read_voltage(&client->dev, "vref");
180890582c2SDavid Lechner if (ret < 0 && ret != -ENODEV)
181733e0fedSLiam Beguin return dev_err_probe(ltc2309->dev, ret,
182890582c2SDavid Lechner "failed to get vref voltage\n");
183733e0fedSLiam Beguin
184890582c2SDavid Lechner ltc2309->vref_mv = ret == -ENODEV ? LTC2309_INTERNAL_REF_MV : ret / 1000;
185733e0fedSLiam Beguin
186733e0fedSLiam Beguin mutex_init(<c2309->lock);
187733e0fedSLiam Beguin
188733e0fedSLiam Beguin return devm_iio_device_register(&client->dev, indio_dev);
189733e0fedSLiam Beguin }
190733e0fedSLiam Beguin
191733e0fedSLiam Beguin static const struct of_device_id ltc2309_of_match[] = {
192733e0fedSLiam Beguin { .compatible = "lltc,ltc2309" },
193733e0fedSLiam Beguin { }
194733e0fedSLiam Beguin };
195733e0fedSLiam Beguin MODULE_DEVICE_TABLE(of, ltc2309_of_match);
196733e0fedSLiam Beguin
197733e0fedSLiam Beguin static const struct i2c_device_id ltc2309_id[] = {
198733e0fedSLiam Beguin { "ltc2309" },
199733e0fedSLiam Beguin { }
200733e0fedSLiam Beguin };
201733e0fedSLiam Beguin MODULE_DEVICE_TABLE(i2c, ltc2309_id);
202733e0fedSLiam Beguin
203733e0fedSLiam Beguin static struct i2c_driver ltc2309_driver = {
204733e0fedSLiam Beguin .driver = {
205733e0fedSLiam Beguin .name = "ltc2309",
206733e0fedSLiam Beguin .of_match_table = ltc2309_of_match,
207733e0fedSLiam Beguin },
208733e0fedSLiam Beguin .probe = ltc2309_probe,
209733e0fedSLiam Beguin .id_table = ltc2309_id,
210733e0fedSLiam Beguin };
211733e0fedSLiam Beguin module_i2c_driver(ltc2309_driver);
212733e0fedSLiam Beguin
213733e0fedSLiam Beguin MODULE_AUTHOR("Liam Beguin <liambeguin@gmail.com>");
214733e0fedSLiam Beguin MODULE_DESCRIPTION("Linear Technology LTC2309 ADC");
215733e0fedSLiam Beguin MODULE_LICENSE("GPL v2");
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