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
29 static const struct regmap_config ltc1660_regmap_config = {
30 .reg_bits = 4,
31 .val_bits = 12,
32 };
33
34 enum ltc1660_supported_device_ids {
35 ID_LTC1660,
36 ID_LTC1665,
37 };
38
39 struct 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
ltc1660_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)47 static 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(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
ltc1660_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)76 static 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(priv->regmap, chan->channel,
94 (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
130 static 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
135 static const struct iio_info ltc1660_info = {
136 .read_raw = <c1660_read_raw,
137 .write_raw = <c1660_write_raw,
138 };
139
ltc1660_suspend(struct device * dev)140 static int __maybe_unused ltc1660_suspend(struct device *dev)
141 {
142 struct ltc1660_priv *priv = iio_priv(spi_get_drvdata(
143 to_spi_device(dev)));
144 return regmap_write(priv->regmap, LTC1660_REG_SLEEP, 0x00);
145 }
146
ltc1660_resume(struct device * dev)147 static int __maybe_unused ltc1660_resume(struct device *dev)
148 {
149 struct ltc1660_priv *priv = iio_priv(spi_get_drvdata(
150 to_spi_device(dev)));
151 return regmap_write(priv->regmap, LTC1660_REG_WAKE, 0x00);
152 }
153 static SIMPLE_DEV_PM_OPS(ltc1660_pm_ops, ltc1660_suspend, ltc1660_resume);
154
ltc1660_probe(struct spi_device * spi)155 static int ltc1660_probe(struct spi_device *spi)
156 {
157 struct iio_dev *indio_dev;
158 struct ltc1660_priv *priv;
159 const struct spi_device_id *id = spi_get_device_id(spi);
160 int ret;
161
162 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*priv));
163 if (indio_dev == NULL)
164 return -ENOMEM;
165
166 priv = iio_priv(indio_dev);
167 priv->regmap = devm_regmap_init_spi(spi, <c1660_regmap_config);
168 if (IS_ERR(priv->regmap)) {
169 dev_err(&spi->dev, "failed to register spi regmap %ld\n",
170 PTR_ERR(priv->regmap));
171 return PTR_ERR(priv->regmap);
172 }
173
174 priv->vref_reg = devm_regulator_get(&spi->dev, "vref");
175 if (IS_ERR(priv->vref_reg)) {
176 dev_err(&spi->dev, "vref regulator not specified\n");
177 return PTR_ERR(priv->vref_reg);
178 }
179
180 ret = regulator_enable(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, indio_dev);
189 indio_dev->info = <c1660_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
204 error_disable_reg:
205 regulator_disable(priv->vref_reg);
206
207 return ret;
208 }
209
ltc1660_remove(struct spi_device * spi)210 static int 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(priv->vref_reg);
217
218 return 0;
219 }
220
221 static const struct of_device_id ltc1660_dt_ids[] = {
222 { .compatible = "lltc,ltc1660", .data = (void *)ID_LTC1660 },
223 { .compatible = "lltc,ltc1665", .data = (void *)ID_LTC1665 },
224 { /* sentinel */ }
225 };
226 MODULE_DEVICE_TABLE(of, ltc1660_dt_ids);
227
228 static const struct spi_device_id ltc1660_id[] = {
229 {"ltc1660", ID_LTC1660},
230 {"ltc1665", ID_LTC1665},
231 { /* sentinel */ }
232 };
233 MODULE_DEVICE_TABLE(spi, ltc1660_id);
234
235 static struct spi_driver ltc1660_driver = {
236 .driver = {
237 .name = "ltc1660",
238 .of_match_table = ltc1660_dt_ids,
239 .pm = <c1660_pm_ops,
240 },
241 .probe = ltc1660_probe,
242 .remove = ltc1660_remove,
243 .id_table = ltc1660_id,
244 };
245 module_spi_driver(ltc1660_driver);
246
247 MODULE_AUTHOR("Marcus Folkesson <marcus.folkesson@gmail.com>");
248 MODULE_DESCRIPTION("Linear Technology LTC1660/LTC1665 DAC");
249 MODULE_LICENSE("GPL v2");
250