1 /*
2 * Driver for Linear Technology LTC1660/LTC1665 DAC
3 *
4 * Copyright (C) 2023 Marcus Folkesson <marcus.folkesson@gmail.com>
5 *
6 * SPDX-License-Identifier: Apache-2.0
7 */
8
9 #include <zephyr/kernel.h>
10 #include <zephyr/drivers/spi.h>
11 #include <zephyr/drivers/dac.h>
12 #include <zephyr/logging/log.h>
13
14 LOG_MODULE_REGISTER(dac_ltc166x, CONFIG_DAC_LOG_LEVEL);
15
16 #define LTC166X_REG_MASK GENMASK(15, 12)
17 #define LTC166X_DATA8_MASK GENMASK(11, 4)
18 #define LTC166X_DATA10_MASK GENMASK(12, 2)
19
20 struct ltc166x_config {
21 struct spi_dt_spec bus;
22 uint8_t resolution;
23 uint8_t nchannels;
24 };
25
ltc166x_reg_write(const struct device * dev,uint8_t addr,uint32_t data)26 static int ltc166x_reg_write(const struct device *dev, uint8_t addr,
27 uint32_t data)
28 {
29 const struct ltc166x_config *config = dev->config;
30 uint16_t regval;
31
32 regval = FIELD_PREP(LTC166X_REG_MASK, addr);
33
34 if (config->resolution == 10) {
35 regval |= FIELD_PREP(LTC166X_DATA10_MASK, data);
36 } else {
37 regval |= FIELD_PREP(LTC166X_DATA8_MASK, data);
38 }
39
40 const struct spi_buf buf = {
41 .buf = ®val,
42 .len = sizeof(regval),
43 };
44
45 struct spi_buf_set tx = {
46 .buffers = &buf,
47 .count = 1,
48 };
49
50 return spi_write_dt(&config->bus, &tx);
51 }
52
53
ltc166x_channel_setup(const struct device * dev,const struct dac_channel_cfg * channel_cfg)54 static int ltc166x_channel_setup(const struct device *dev,
55 const struct dac_channel_cfg *channel_cfg)
56 {
57 const struct ltc166x_config *config = dev->config;
58
59 if (channel_cfg->channel_id > config->nchannels - 1) {
60 LOG_ERR("Unsupported channel %d", channel_cfg->channel_id);
61 return -ENOTSUP;
62 }
63
64 if (channel_cfg->resolution != config->resolution) {
65 LOG_ERR("Unsupported resolution %d", channel_cfg->resolution);
66 return -ENOTSUP;
67 }
68
69 if (channel_cfg->internal) {
70 LOG_ERR("Internal channels not supported");
71 return -ENOTSUP;
72 }
73
74 return 0;
75 }
76
ltc166x_write_value(const struct device * dev,uint8_t channel,uint32_t value)77 static int ltc166x_write_value(const struct device *dev, uint8_t channel,
78 uint32_t value)
79 {
80 const struct ltc166x_config *config = dev->config;
81
82 if (channel > config->nchannels - 1) {
83 LOG_ERR("unsupported channel %d", channel);
84 return -ENOTSUP;
85 }
86
87 if (value >= (1 << config->resolution)) {
88 LOG_ERR("Value %d out of range", value);
89 return -EINVAL;
90 }
91
92 return ltc166x_reg_write(dev, channel + 1, value);
93 }
94
ltc166x_init(const struct device * dev)95 static int ltc166x_init(const struct device *dev)
96 {
97 const struct ltc166x_config *config = dev->config;
98
99 if (!spi_is_ready_dt(&config->bus)) {
100 LOG_ERR("SPI bus %s not ready", config->bus.bus->name);
101 return -ENODEV;
102 }
103 return 0;
104 }
105
106 static DEVICE_API(dac, ltc166x_driver_api) = {
107 .channel_setup = ltc166x_channel_setup,
108 .write_value = ltc166x_write_value,
109 };
110
111
112 #define INST_DT_LTC166X(inst, t) DT_INST(inst, lltc_ltc##t)
113
114 #define LTC166X_DEVICE(t, n, res, nchan) \
115 static const struct ltc166x_config ltc##t##_config_##n = { \
116 .bus = SPI_DT_SPEC_GET(INST_DT_LTC166X(n, t), \
117 SPI_OP_MODE_MASTER | \
118 SPI_WORD_SET(8), 0), \
119 .resolution = res, \
120 .nchannels = nchan, \
121 }; \
122 DEVICE_DT_DEFINE(INST_DT_LTC166X(n, t), \
123 <c166x_init, NULL, \
124 NULL, \
125 <c##t##_config_##n, POST_KERNEL, \
126 CONFIG_DAC_LTC166X_INIT_PRIORITY, \
127 <c166x_driver_api)
128
129 /*
130 * LTC1660: 10-bit
131 */
132 #define LTC1660_DEVICE(n) LTC166X_DEVICE(1660, n, 10, 8)
133
134 /*
135 * LTC1665: 8-bit
136 */
137 #define LTC1665_DEVICE(n) LTC166X_DEVICE(1665, n, 8, 8)
138
139 #define CALL_WITH_ARG(arg, expr) expr(arg)
140
141 #define INST_DT_LTC166X_FOREACH(t, inst_expr) \
142 LISTIFY(DT_NUM_INST_STATUS_OKAY(lltc_ltc##t), \
143 CALL_WITH_ARG, (), inst_expr)
144
145 INST_DT_LTC166X_FOREACH(1660, LTC1660_DEVICE);
146 INST_DT_LTC166X_FOREACH(1665, LTC1665_DEVICE);
147
