xref: /openbmc/linux/drivers/iio/adc/ti-adc128s052.c (revision 4b570fe0)
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