1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2014 Angelo Compagnucci <angelo.compagnucci@gmail.com>
4 *
5 * Driver for Texas Instruments' ADC128S052, ADC122S021 and ADC124S021 ADC chip.
6 * Datasheets can be found here:
7 * https://www.ti.com/lit/ds/symlink/adc128s052.pdf
8 * https://www.ti.com/lit/ds/symlink/adc122s021.pdf
9 * https://www.ti.com/lit/ds/symlink/adc124s021.pdf
10 */
11
12 #include <linux/err.h>
13 #include <linux/iio/iio.h>
14 #include <linux/mod_devicetable.h>
15 #include <linux/module.h>
16 #include <linux/property.h>
17 #include <linux/regulator/consumer.h>
18 #include <linux/spi/spi.h>
19
20 struct adc128_configuration {
21 const struct iio_chan_spec *channels;
22 u8 num_channels;
23 };
24
25 struct adc128 {
26 struct spi_device *spi;
27
28 struct regulator *reg;
29 struct mutex lock;
30
31 u8 buffer[2] __aligned(IIO_DMA_MINALIGN);
32 };
33
adc128_adc_conversion(struct adc128 * adc,u8 channel)34 static int adc128_adc_conversion(struct adc128 *adc, u8 channel)
35 {
36 int ret;
37
38 mutex_lock(&adc->lock);
39
40 adc->buffer[0] = channel << 3;
41 adc->buffer[1] = 0;
42
43 ret = spi_write(adc->spi, &adc->buffer, 2);
44 if (ret < 0) {
45 mutex_unlock(&adc->lock);
46 return ret;
47 }
48
49 ret = spi_read(adc->spi, &adc->buffer, 2);
50
51 mutex_unlock(&adc->lock);
52
53 if (ret < 0)
54 return ret;
55
56 return ((adc->buffer[0] << 8 | adc->buffer[1]) & 0xFFF);
57 }
58
adc128_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * channel,int * val,int * val2,long mask)59 static int adc128_read_raw(struct iio_dev *indio_dev,
60 struct iio_chan_spec const *channel, int *val,
61 int *val2, long mask)
62 {
63 struct adc128 *adc = iio_priv(indio_dev);
64 int ret;
65
66 switch (mask) {
67 case IIO_CHAN_INFO_RAW:
68
69 ret = adc128_adc_conversion(adc, channel->channel);
70 if (ret < 0)
71 return ret;
72
73 *val = ret;
74 return IIO_VAL_INT;
75
76 case IIO_CHAN_INFO_SCALE:
77
78 ret = regulator_get_voltage(adc->reg);
79 if (ret < 0)
80 return ret;
81
82 *val = ret / 1000;
83 *val2 = 12;
84 return IIO_VAL_FRACTIONAL_LOG2;
85
86 default:
87 return -EINVAL;
88 }
89
90 }
91
92 #define ADC128_VOLTAGE_CHANNEL(num) \
93 { \
94 .type = IIO_VOLTAGE, \
95 .indexed = 1, \
96 .channel = (num), \
97 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
98 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
99 }
100
101 static const struct iio_chan_spec adc128s052_channels[] = {
102 ADC128_VOLTAGE_CHANNEL(0),
103 ADC128_VOLTAGE_CHANNEL(1),
104 ADC128_VOLTAGE_CHANNEL(2),
105 ADC128_VOLTAGE_CHANNEL(3),
106 ADC128_VOLTAGE_CHANNEL(4),
107 ADC128_VOLTAGE_CHANNEL(5),
108 ADC128_VOLTAGE_CHANNEL(6),
109 ADC128_VOLTAGE_CHANNEL(7),
110 };
111
112 static const struct iio_chan_spec adc122s021_channels[] = {
113 ADC128_VOLTAGE_CHANNEL(0),
114 ADC128_VOLTAGE_CHANNEL(1),
115 };
116
117 static const struct iio_chan_spec adc124s021_channels[] = {
118 ADC128_VOLTAGE_CHANNEL(0),
119 ADC128_VOLTAGE_CHANNEL(1),
120 ADC128_VOLTAGE_CHANNEL(2),
121 ADC128_VOLTAGE_CHANNEL(3),
122 };
123
124 static const struct adc128_configuration adc128_config[] = {
125 { adc128s052_channels, ARRAY_SIZE(adc128s052_channels) },
126 { adc122s021_channels, ARRAY_SIZE(adc122s021_channels) },
127 { adc124s021_channels, ARRAY_SIZE(adc124s021_channels) },
128 };
129
130 static const struct iio_info adc128_info = {
131 .read_raw = adc128_read_raw,
132 };
133
adc128_disable_regulator(void * reg)134 static void adc128_disable_regulator(void *reg)
135 {
136 regulator_disable(reg);
137 }
138
adc128_probe(struct spi_device * spi)139 static int adc128_probe(struct spi_device *spi)
140 {
141 const struct adc128_configuration *config;
142 struct iio_dev *indio_dev;
143 struct adc128 *adc;
144 int ret;
145
146 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
147 if (!indio_dev)
148 return -ENOMEM;
149
150 adc = iio_priv(indio_dev);
151 adc->spi = spi;
152
153 indio_dev->name = spi_get_device_id(spi)->name;
154 indio_dev->modes = INDIO_DIRECT_MODE;
155 indio_dev->info = &adc128_info;
156
157 config = spi_get_device_match_data(spi);
158
159 indio_dev->channels = config->channels;
160 indio_dev->num_channels = config->num_channels;
161
162 adc->reg = devm_regulator_get(&spi->dev, "vref");
163 if (IS_ERR(adc->reg))
164 return PTR_ERR(adc->reg);
165
166 ret = regulator_enable(adc->reg);
167 if (ret < 0)
168 return ret;
169 ret = devm_add_action_or_reset(&spi->dev, adc128_disable_regulator,
170 adc->reg);
171 if (ret)
172 return ret;
173
174 mutex_init(&adc->lock);
175
176 return devm_iio_device_register(&spi->dev, indio_dev);
177 }
178
179 static const struct of_device_id adc128_of_match[] = {
180 { .compatible = "ti,adc128s052", .data = &adc128_config[0] },
181 { .compatible = "ti,adc122s021", .data = &adc128_config[1] },
182 { .compatible = "ti,adc122s051", .data = &adc128_config[1] },
183 { .compatible = "ti,adc122s101", .data = &adc128_config[1] },
184 { .compatible = "ti,adc124s021", .data = &adc128_config[2] },
185 { .compatible = "ti,adc124s051", .data = &adc128_config[2] },
186 { .compatible = "ti,adc124s101", .data = &adc128_config[2] },
187 { /* sentinel */ },
188 };
189 MODULE_DEVICE_TABLE(of, adc128_of_match);
190
191 static const struct spi_device_id adc128_id[] = {
192 { "adc128s052", (kernel_ulong_t)&adc128_config[0] },
193 { "adc122s021", (kernel_ulong_t)&adc128_config[1] },
194 { "adc122s051", (kernel_ulong_t)&adc128_config[1] },
195 { "adc122s101", (kernel_ulong_t)&adc128_config[1] },
196 { "adc124s021", (kernel_ulong_t)&adc128_config[2] },
197 { "adc124s051", (kernel_ulong_t)&adc128_config[2] },
198 { "adc124s101", (kernel_ulong_t)&adc128_config[2] },
199 { }
200 };
201 MODULE_DEVICE_TABLE(spi, adc128_id);
202
203 static const struct acpi_device_id adc128_acpi_match[] = {
204 { "AANT1280", (kernel_ulong_t)&adc128_config[2] },
205 { }
206 };
207 MODULE_DEVICE_TABLE(acpi, adc128_acpi_match);
208
209 static struct spi_driver adc128_driver = {
210 .driver = {
211 .name = "adc128s052",
212 .of_match_table = adc128_of_match,
213 .acpi_match_table = adc128_acpi_match,
214 },
215 .probe = adc128_probe,
216 .id_table = adc128_id,
217 };
218 module_spi_driver(adc128_driver);
219
220 MODULE_AUTHOR("Angelo Compagnucci <angelo.compagnucci@gmail.com>");
221 MODULE_DESCRIPTION("Texas Instruments ADC128S052");
222 MODULE_LICENSE("GPL v2");
223