1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Driver for Linear Technology LTC1665/LTC1660, 8 channels DAC
4 *
5 * Copyright (C) 2018 Marcus Folkesson <marcus.folkesson@gmail.com>
6 */
7#include <linux/bitops.h>
8#include <linux/iio/iio.h>
9#include <linux/iio/sysfs.h>
10#include <linux/init.h>
11#include <linux/module.h>
12#include <linux/regulator/consumer.h>
13#include <linux/regmap.h>
14#include <linux/spi/spi.h>
15
16#define LTC1660_REG_WAKE 0x0
17#define LTC1660_REG_DAC_A 0x1
18#define LTC1660_REG_DAC_B 0x2
19#define LTC1660_REG_DAC_C 0x3
20#define LTC1660_REG_DAC_D 0x4
21#define LTC1660_REG_DAC_E 0x5
22#define LTC1660_REG_DAC_F 0x6
23#define LTC1660_REG_DAC_G 0x7
24#define LTC1660_REG_DAC_H 0x8
25#define LTC1660_REG_SLEEP 0xe
26
27#define LTC1660_NUM_CHANNELS 8
28
29static const struct regmap_config ltc1660_regmap_config = {
30 .reg_bits = 4,
31 .val_bits = 12,
32};
33
34enum ltc1660_supported_device_ids {
35 ID_LTC1660,
36 ID_LTC1665,
37};
38
39struct ltc1660_priv {
40 struct spi_device *spi;
41 struct regmap *regmap;
42 struct regulator *vref_reg;
43 unsigned int value[LTC1660_NUM_CHANNELS];
44 unsigned int vref_mv;
45};
46
47static int ltc1660_read_raw(struct iio_dev *indio_dev,
48 struct iio_chan_spec const *chan,
49 int *val,
50 int *val2,
51 long mask)
52{
53 struct ltc1660_priv *priv = iio_priv(indio_dev);
54
55 switch (mask) {
56 case IIO_CHAN_INFO_RAW:
57 *val = priv->value[chan->channel];
58 return IIO_VAL_INT;
59 case IIO_CHAN_INFO_SCALE:
60 *val = regulator_get_voltage(regulator: priv->vref_reg);
61 if (*val < 0) {
62 dev_err(&priv->spi->dev, "failed to read vref regulator: %d\n",
63 *val);
64 return *val;
65 }
66
67 /* Convert to mV */
68 *val /= 1000;
69 *val2 = chan->scan_type.realbits;
70 return IIO_VAL_FRACTIONAL_LOG2;
71 default:
72 return -EINVAL;
73 }
74}
75
76static int ltc1660_write_raw(struct iio_dev *indio_dev,
77 struct iio_chan_spec const *chan,
78 int val,
79 int val2,
80 long mask)
81{
82 struct ltc1660_priv *priv = iio_priv(indio_dev);
83 int ret;
84
85 switch (mask) {
86 case IIO_CHAN_INFO_RAW:
87 if (val2 != 0)
88 return -EINVAL;
89
90 if (val < 0 || val > GENMASK(chan->scan_type.realbits - 1, 0))
91 return -EINVAL;
92
93 ret = regmap_write(map: priv->regmap, reg: chan->channel,
94 val: (val << chan->scan_type.shift));
95 if (!ret)
96 priv->value[chan->channel] = val;
97
98 return ret;
99 default:
100 return -EINVAL;
101 }
102}
103
104#define LTC1660_CHAN(chan, bits) { \
105 .type = IIO_VOLTAGE, \
106 .indexed = 1, \
107 .output = 1, \
108 .channel = chan, \
109 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
110 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
111 .scan_type = { \
112 .sign = 'u', \
113 .realbits = (bits), \
114 .storagebits = 16, \
115 .shift = 12 - (bits), \
116 }, \
117}
118
119#define LTC1660_OCTAL_CHANNELS(bits) { \
120 LTC1660_CHAN(LTC1660_REG_DAC_A, bits), \
121 LTC1660_CHAN(LTC1660_REG_DAC_B, bits), \
122 LTC1660_CHAN(LTC1660_REG_DAC_C, bits), \
123 LTC1660_CHAN(LTC1660_REG_DAC_D, bits), \
124 LTC1660_CHAN(LTC1660_REG_DAC_E, bits), \
125 LTC1660_CHAN(LTC1660_REG_DAC_F, bits), \
126 LTC1660_CHAN(LTC1660_REG_DAC_G, bits), \
127 LTC1660_CHAN(LTC1660_REG_DAC_H, bits), \
128}
129
130static const struct iio_chan_spec ltc1660_channels[][LTC1660_NUM_CHANNELS] = {
131 [ID_LTC1660] = LTC1660_OCTAL_CHANNELS(10),
132 [ID_LTC1665] = LTC1660_OCTAL_CHANNELS(8),
133};
134
135static const struct iio_info ltc1660_info = {
136 .read_raw = &ltc1660_read_raw,
137 .write_raw = &ltc1660_write_raw,
138};
139
140static int ltc1660_suspend(struct device *dev)
141{
142 struct ltc1660_priv *priv = iio_priv(indio_dev: spi_get_drvdata(
143 spi: to_spi_device(dev)));
144 return regmap_write(map: priv->regmap, LTC1660_REG_SLEEP, val: 0x00);
145}
146
147static int ltc1660_resume(struct device *dev)
148{
149 struct ltc1660_priv *priv = iio_priv(indio_dev: spi_get_drvdata(
150 spi: to_spi_device(dev)));
151 return regmap_write(map: priv->regmap, LTC1660_REG_WAKE, val: 0x00);
152}
153static DEFINE_SIMPLE_DEV_PM_OPS(ltc1660_pm_ops, ltc1660_suspend,
154 ltc1660_resume);
155
156static int ltc1660_probe(struct spi_device *spi)
157{
158 struct iio_dev *indio_dev;
159 struct ltc1660_priv *priv;
160 const struct spi_device_id *id = spi_get_device_id(sdev: spi);
161 int ret;
162
163 indio_dev = devm_iio_device_alloc(parent: &spi->dev, sizeof_priv: sizeof(*priv));
164 if (indio_dev == NULL)
165 return -ENOMEM;
166
167 priv = iio_priv(indio_dev);
168 priv->regmap = devm_regmap_init_spi(spi, &ltc1660_regmap_config);
169 if (IS_ERR(ptr: priv->regmap)) {
170 dev_err(&spi->dev, "failed to register spi regmap %ld\n",
171 PTR_ERR(priv->regmap));
172 return PTR_ERR(ptr: priv->regmap);
173 }
174
175 priv->vref_reg = devm_regulator_get(dev: &spi->dev, id: "vref");
176 if (IS_ERR(ptr: priv->vref_reg))
177 return dev_err_probe(dev: &spi->dev, err: PTR_ERR(ptr: priv->vref_reg),
178 fmt: "vref regulator not specified\n");
179
180 ret = regulator_enable(regulator: priv->vref_reg);
181 if (ret) {
182 dev_err(&spi->dev, "failed to enable vref regulator: %d\n",
183 ret);
184 return ret;
185 }
186
187 priv->spi = spi;
188 spi_set_drvdata(spi, data: indio_dev);
189 indio_dev->info = &ltc1660_info;
190 indio_dev->modes = INDIO_DIRECT_MODE;
191 indio_dev->channels = ltc1660_channels[id->driver_data];
192 indio_dev->num_channels = LTC1660_NUM_CHANNELS;
193 indio_dev->name = id->name;
194
195 ret = iio_device_register(indio_dev);
196 if (ret) {
197 dev_err(&spi->dev, "failed to register iio device: %d\n",
198 ret);
199 goto error_disable_reg;
200 }
201
202 return 0;
203
204error_disable_reg:
205 regulator_disable(regulator: priv->vref_reg);
206
207 return ret;
208}
209
210static void ltc1660_remove(struct spi_device *spi)
211{
212 struct iio_dev *indio_dev = spi_get_drvdata(spi);
213 struct ltc1660_priv *priv = iio_priv(indio_dev);
214
215 iio_device_unregister(indio_dev);
216 regulator_disable(regulator: priv->vref_reg);
217}
218
219static const struct of_device_id ltc1660_dt_ids[] = {
220 { .compatible = "lltc,ltc1660", .data = (void *)ID_LTC1660 },
221 { .compatible = "lltc,ltc1665", .data = (void *)ID_LTC1665 },
222 { /* sentinel */ }
223};
224MODULE_DEVICE_TABLE(of, ltc1660_dt_ids);
225
226static const struct spi_device_id ltc1660_id[] = {
227 {"ltc1660", ID_LTC1660},
228 {"ltc1665", ID_LTC1665},
229 { /* sentinel */ }
230};
231MODULE_DEVICE_TABLE(spi, ltc1660_id);
232
233static struct spi_driver ltc1660_driver = {
234 .driver = {
235 .name = "ltc1660",
236 .of_match_table = ltc1660_dt_ids,
237 .pm = pm_sleep_ptr(&ltc1660_pm_ops),
238 },
239 .probe = ltc1660_probe,
240 .remove = ltc1660_remove,
241 .id_table = ltc1660_id,
242};
243module_spi_driver(ltc1660_driver);
244
245MODULE_AUTHOR("Marcus Folkesson <marcus.folkesson@gmail.com>");
246MODULE_DESCRIPTION("Linear Technology LTC1660/LTC1665 DAC");
247MODULE_LICENSE("GPL v2");
248

source code of linux/drivers/iio/dac/ltc1660.c