1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * TI ADC081C/ADC101C/ADC121C 8/10/12-bit ADC driver
4 *
5 * Copyright (C) 2012 Avionic Design GmbH
6 * Copyright (C) 2016 Intel
7 *
8 * Datasheets:
9 * https://www.ti.com/lit/ds/symlink/adc081c021.pdf
10 * https://www.ti.com/lit/ds/symlink/adc101c021.pdf
11 * https://www.ti.com/lit/ds/symlink/adc121c021.pdf
12 *
13 * The devices have a very similar interface and differ mostly in the number of
14 * bits handled. For the 8-bit and 10-bit models the least-significant 4 or 2
15 * bits of value registers are reserved.
16 */
17
18 #include <linux/err.h>
19 #include <linux/i2c.h>
20 #include <linux/module.h>
21 #include <linux/mod_devicetable.h>
22 #include <linux/property.h>
23
24 #include <linux/iio/iio.h>
25 #include <linux/iio/buffer.h>
26 #include <linux/iio/trigger_consumer.h>
27 #include <linux/iio/triggered_buffer.h>
28 #include <linux/regulator/consumer.h>
29
30 struct adc081c {
31 struct i2c_client *i2c;
32 struct regulator *ref;
33
34 /* 8, 10 or 12 */
35 int bits;
36
37 /* Ensure natural alignment of buffer elements */
38 struct {
39 u16 channel;
40 s64 ts __aligned(8);
41 } scan;
42 };
43
44 #define REG_CONV_RES 0x00
45
adc081c_read_raw(struct iio_dev * iio,struct iio_chan_spec const * channel,int * value,int * shift,long mask)46 static int adc081c_read_raw(struct iio_dev *iio,
47 struct iio_chan_spec const *channel, int *value,
48 int *shift, long mask)
49 {
50 struct adc081c *adc = iio_priv(iio);
51 int err;
52
53 switch (mask) {
54 case IIO_CHAN_INFO_RAW:
55 err = i2c_smbus_read_word_swapped(adc->i2c, REG_CONV_RES);
56 if (err < 0)
57 return err;
58
59 *value = (err & 0xFFF) >> (12 - adc->bits);
60 return IIO_VAL_INT;
61
62 case IIO_CHAN_INFO_SCALE:
63 err = regulator_get_voltage(adc->ref);
64 if (err < 0)
65 return err;
66
67 *value = err / 1000;
68 *shift = adc->bits;
69
70 return IIO_VAL_FRACTIONAL_LOG2;
71
72 default:
73 break;
74 }
75
76 return -EINVAL;
77 }
78
79 #define ADCxx1C_CHAN(_bits) { \
80 .type = IIO_VOLTAGE, \
81 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
82 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
83 .scan_type = { \
84 .sign = 'u', \
85 .realbits = (_bits), \
86 .storagebits = 16, \
87 .shift = 12 - (_bits), \
88 .endianness = IIO_CPU, \
89 }, \
90 }
91
92 #define DEFINE_ADCxx1C_CHANNELS(_name, _bits) \
93 static const struct iio_chan_spec _name ## _channels[] = { \
94 ADCxx1C_CHAN((_bits)), \
95 IIO_CHAN_SOFT_TIMESTAMP(1), \
96 }; \
97
98 #define ADC081C_NUM_CHANNELS 2
99
100 struct adcxx1c_model {
101 const struct iio_chan_spec* channels;
102 int bits;
103 };
104
105 #define ADCxx1C_MODEL(_name, _bits) \
106 { \
107 .channels = _name ## _channels, \
108 .bits = (_bits), \
109 }
110
111 DEFINE_ADCxx1C_CHANNELS(adc081c, 8);
112 DEFINE_ADCxx1C_CHANNELS(adc101c, 10);
113 DEFINE_ADCxx1C_CHANNELS(adc121c, 12);
114
115 /* Model ids are indexes in _models array */
116 enum adcxx1c_model_id {
117 ADC081C = 0,
118 ADC101C = 1,
119 ADC121C = 2,
120 };
121
122 static struct adcxx1c_model adcxx1c_models[] = {
123 ADCxx1C_MODEL(adc081c, 8),
124 ADCxx1C_MODEL(adc101c, 10),
125 ADCxx1C_MODEL(adc121c, 12),
126 };
127
128 static const struct iio_info adc081c_info = {
129 .read_raw = adc081c_read_raw,
130 };
131
adc081c_trigger_handler(int irq,void * p)132 static irqreturn_t adc081c_trigger_handler(int irq, void *p)
133 {
134 struct iio_poll_func *pf = p;
135 struct iio_dev *indio_dev = pf->indio_dev;
136 struct adc081c *data = iio_priv(indio_dev);
137 int ret;
138
139 ret = i2c_smbus_read_word_swapped(data->i2c, REG_CONV_RES);
140 if (ret < 0)
141 goto out;
142 data->scan.channel = ret;
143 iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
144 iio_get_time_ns(indio_dev));
145 out:
146 iio_trigger_notify_done(indio_dev->trig);
147 return IRQ_HANDLED;
148 }
149
adc081c_reg_disable(void * reg)150 static void adc081c_reg_disable(void *reg)
151 {
152 regulator_disable(reg);
153 }
154
adc081c_probe(struct i2c_client * client)155 static int adc081c_probe(struct i2c_client *client)
156 {
157 struct iio_dev *iio;
158 struct adc081c *adc;
159 const struct adcxx1c_model *model;
160 int err;
161
162 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
163 return -EOPNOTSUPP;
164
165 model = i2c_get_match_data(client);
166
167 iio = devm_iio_device_alloc(&client->dev, sizeof(*adc));
168 if (!iio)
169 return -ENOMEM;
170
171 adc = iio_priv(iio);
172 adc->i2c = client;
173 adc->bits = model->bits;
174
175 adc->ref = devm_regulator_get(&client->dev, "vref");
176 if (IS_ERR(adc->ref))
177 return PTR_ERR(adc->ref);
178
179 err = regulator_enable(adc->ref);
180 if (err < 0)
181 return err;
182
183 err = devm_add_action_or_reset(&client->dev, adc081c_reg_disable,
184 adc->ref);
185 if (err)
186 return err;
187
188 iio->name = dev_name(&client->dev);
189 iio->modes = INDIO_DIRECT_MODE;
190 iio->info = &adc081c_info;
191
192 iio->channels = model->channels;
193 iio->num_channels = ADC081C_NUM_CHANNELS;
194
195 err = devm_iio_triggered_buffer_setup(&client->dev, iio, NULL,
196 adc081c_trigger_handler, NULL);
197 if (err < 0) {
198 dev_err(&client->dev, "iio triggered buffer setup failed\n");
199 return err;
200 }
201
202 return devm_iio_device_register(&client->dev, iio);
203 }
204
205 static const struct i2c_device_id adc081c_id[] = {
206 { "adc081c", (kernel_ulong_t)&adcxx1c_models[ADC081C] },
207 { "adc101c", (kernel_ulong_t)&adcxx1c_models[ADC101C] },
208 { "adc121c", (kernel_ulong_t)&adcxx1c_models[ADC121C] },
209 { }
210 };
211 MODULE_DEVICE_TABLE(i2c, adc081c_id);
212
213 static const struct acpi_device_id adc081c_acpi_match[] = {
214 /* Used on some AAEON boards */
215 { "ADC081C", (kernel_ulong_t)&adcxx1c_models[ADC081C] },
216 { }
217 };
218 MODULE_DEVICE_TABLE(acpi, adc081c_acpi_match);
219
220 static const struct of_device_id adc081c_of_match[] = {
221 { .compatible = "ti,adc081c", .data = &adcxx1c_models[ADC081C] },
222 { .compatible = "ti,adc101c", .data = &adcxx1c_models[ADC101C] },
223 { .compatible = "ti,adc121c", .data = &adcxx1c_models[ADC121C] },
224 { }
225 };
226 MODULE_DEVICE_TABLE(of, adc081c_of_match);
227
228 static struct i2c_driver adc081c_driver = {
229 .driver = {
230 .name = "adc081c",
231 .of_match_table = adc081c_of_match,
232 .acpi_match_table = adc081c_acpi_match,
233 },
234 .probe = adc081c_probe,
235 .id_table = adc081c_id,
236 };
237 module_i2c_driver(adc081c_driver);
238
239 MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
240 MODULE_DESCRIPTION("Texas Instruments ADC081C/ADC101C/ADC121C driver");
241 MODULE_LICENSE("GPL v2");
242