1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Maxim MAX5522
4 * Dual, Ultra-Low-Power 10-Bit, Voltage-Output DACs
5 *
6 * Copyright 2022 Timesys Corp.
7 */
8
9 #include <linux/device.h>
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/mod_devicetable.h>
13 #include <linux/regmap.h>
14 #include <linux/regulator/consumer.h>
15 #include <linux/slab.h>
16 #include <linux/spi/spi.h>
17
18 #include <linux/iio/iio.h>
19
20 #define MAX5522_MAX_ADDR 15
21 #define MAX5522_CTRL_NONE 0
22 #define MAX5522_CTRL_LOAD_IN_A 9
23 #define MAX5522_CTRL_LOAD_IN_B 10
24
25 #define MAX5522_REG_DATA(x) ((x) + MAX5522_CTRL_LOAD_IN_A)
26
27 struct max5522_chip_info {
28 const char *name;
29 const struct iio_chan_spec *channels;
30 unsigned int num_channels;
31 };
32
33 struct max5522_state {
34 struct regmap *regmap;
35 const struct max5522_chip_info *chip_info;
36 unsigned short dac_cache[2];
37 struct regulator *vrefin_reg;
38 };
39
40 #define MAX5522_CHANNEL(chan) { \
41 .type = IIO_VOLTAGE, \
42 .indexed = 1, \
43 .output = 1, \
44 .channel = chan, \
45 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
46 BIT(IIO_CHAN_INFO_SCALE), \
47 .scan_type = { \
48 .sign = 'u', \
49 .realbits = 10, \
50 .storagebits = 16, \
51 .shift = 2, \
52 } \
53 }
54
55 static const struct iio_chan_spec max5522_channels[] = {
56 MAX5522_CHANNEL(0),
57 MAX5522_CHANNEL(1),
58 };
59
60 enum max5522_type {
61 ID_MAX5522,
62 };
63
64 static const struct max5522_chip_info max5522_chip_info_tbl[] = {
65 [ID_MAX5522] = {
66 .name = "max5522",
67 .channels = max5522_channels,
68 .num_channels = 2,
69 },
70 };
71
max5522_info_to_reg(struct iio_chan_spec const * chan)72 static inline int max5522_info_to_reg(struct iio_chan_spec const *chan)
73 {
74 return MAX5522_REG_DATA(chan->channel);
75 }
76
max5522_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long info)77 static int max5522_read_raw(struct iio_dev *indio_dev,
78 struct iio_chan_spec const *chan,
79 int *val, int *val2, long info)
80 {
81 struct max5522_state *state = iio_priv(indio_dev);
82 int ret;
83
84 switch (info) {
85 case IIO_CHAN_INFO_RAW:
86 *val = state->dac_cache[chan->channel];
87 return IIO_VAL_INT;
88 case IIO_CHAN_INFO_SCALE:
89 ret = regulator_get_voltage(state->vrefin_reg);
90 if (ret < 0)
91 return -EINVAL;
92 *val = ret / 1000;
93 *val2 = 10;
94 return IIO_VAL_FRACTIONAL_LOG2;
95 default:
96 return -EINVAL;
97 }
98
99 return -EINVAL;
100 }
101
max5522_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long info)102 static int max5522_write_raw(struct iio_dev *indio_dev,
103 struct iio_chan_spec const *chan,
104 int val, int val2, long info)
105 {
106 struct max5522_state *state = iio_priv(indio_dev);
107 int rval;
108
109 if (val > 1023 || val < 0)
110 return -EINVAL;
111
112 rval = regmap_write(state->regmap, max5522_info_to_reg(chan),
113 val << chan->scan_type.shift);
114 if (rval < 0)
115 return rval;
116
117 state->dac_cache[chan->channel] = val;
118
119 return 0;
120 }
121
122 static const struct iio_info max5522_info = {
123 .read_raw = max5522_read_raw,
124 .write_raw = max5522_write_raw,
125 };
126
127 static const struct regmap_config max5522_regmap_config = {
128 .reg_bits = 4,
129 .val_bits = 12,
130 .max_register = MAX5522_MAX_ADDR,
131 };
132
max5522_spi_probe(struct spi_device * spi)133 static int max5522_spi_probe(struct spi_device *spi)
134 {
135 struct iio_dev *indio_dev;
136 struct max5522_state *state;
137 int ret;
138
139 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*state));
140 if (indio_dev == NULL) {
141 dev_err(&spi->dev, "failed to allocate iio device\n");
142 return -ENOMEM;
143 }
144
145 state = iio_priv(indio_dev);
146 state->chip_info = spi_get_device_match_data(spi);
147 if (!state->chip_info)
148 return -EINVAL;
149
150 state->vrefin_reg = devm_regulator_get(&spi->dev, "vrefin");
151 if (IS_ERR(state->vrefin_reg))
152 return dev_err_probe(&spi->dev, PTR_ERR(state->vrefin_reg),
153 "Vrefin regulator not specified\n");
154
155 ret = regulator_enable(state->vrefin_reg);
156 if (ret) {
157 return dev_err_probe(&spi->dev, ret,
158 "Failed to enable vref regulators\n");
159 }
160
161 state->regmap = devm_regmap_init_spi(spi, &max5522_regmap_config);
162
163 if (IS_ERR(state->regmap))
164 return PTR_ERR(state->regmap);
165
166 indio_dev->info = &max5522_info;
167 indio_dev->modes = INDIO_DIRECT_MODE;
168 indio_dev->channels = max5522_channels;
169 indio_dev->num_channels = ARRAY_SIZE(max5522_channels);
170 indio_dev->name = max5522_chip_info_tbl[ID_MAX5522].name;
171
172 return devm_iio_device_register(&spi->dev, indio_dev);
173 }
174
175 static const struct spi_device_id max5522_ids[] = {
176 { "max5522", (kernel_ulong_t)&max5522_chip_info_tbl[ID_MAX5522] },
177 {}
178 };
179 MODULE_DEVICE_TABLE(spi, max5522_ids);
180
181 static const struct of_device_id max5522_of_match[] = {
182 {
183 .compatible = "maxim,max5522",
184 .data = &max5522_chip_info_tbl[ID_MAX5522],
185 },
186 {}
187 };
188 MODULE_DEVICE_TABLE(of, max5522_of_match);
189
190 static struct spi_driver max5522_spi_driver = {
191 .driver = {
192 .name = "max5522",
193 .of_match_table = max5522_of_match,
194 },
195 .probe = max5522_spi_probe,
196 .id_table = max5522_ids,
197 };
198 module_spi_driver(max5522_spi_driver);
199
200 MODULE_AUTHOR("Angelo Dureghello <angelo.dureghello@timesys.com");
201 MODULE_DESCRIPTION("MAX5522 DAC driver");
202 MODULE_LICENSE("GPL");
203