1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * ti-adc161s626.c - Texas Instruments ADC161S626 1-channel differential ADC
4 *
5 * ADC Devices Supported:
6 * adc141s626 - 14-bit ADC
7 * adc161s626 - 16-bit ADC
8 *
9 * Copyright (C) 2016-2018
10 * Author: Matt Ranostay <matt.ranostay@konsulko.com>
11 */
12
13 #include <linux/module.h>
14 #include <linux/mod_devicetable.h>
15 #include <linux/init.h>
16 #include <linux/err.h>
17 #include <linux/spi/spi.h>
18 #include <linux/iio/iio.h>
19 #include <linux/iio/trigger.h>
20 #include <linux/iio/buffer.h>
21 #include <linux/iio/trigger_consumer.h>
22 #include <linux/iio/triggered_buffer.h>
23 #include <linux/regulator/consumer.h>
24
25 #define TI_ADC_DRV_NAME "ti-adc161s626"
26
27 enum {
28 TI_ADC141S626,
29 TI_ADC161S626,
30 };
31
32 static const struct iio_chan_spec ti_adc141s626_channels[] = {
33 {
34 .type = IIO_VOLTAGE,
35 .channel = 0,
36 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
37 BIT(IIO_CHAN_INFO_SCALE) |
38 BIT(IIO_CHAN_INFO_OFFSET),
39 .scan_index = 0,
40 .scan_type = {
41 .sign = 's',
42 .realbits = 14,
43 .storagebits = 16,
44 },
45 },
46 IIO_CHAN_SOFT_TIMESTAMP(1),
47 };
48
49 static const struct iio_chan_spec ti_adc161s626_channels[] = {
50 {
51 .type = IIO_VOLTAGE,
52 .channel = 0,
53 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
54 BIT(IIO_CHAN_INFO_SCALE) |
55 BIT(IIO_CHAN_INFO_OFFSET),
56 .scan_index = 0,
57 .scan_type = {
58 .sign = 's',
59 .realbits = 16,
60 .storagebits = 16,
61 },
62 },
63 IIO_CHAN_SOFT_TIMESTAMP(1),
64 };
65
66 struct ti_adc_data {
67 struct iio_dev *indio_dev;
68 struct spi_device *spi;
69 struct regulator *ref;
70
71 u8 read_size;
72 u8 shift;
73
74 u8 buffer[16] __aligned(IIO_DMA_MINALIGN);
75 };
76
ti_adc_read_measurement(struct ti_adc_data * data,struct iio_chan_spec const * chan,int * val)77 static int ti_adc_read_measurement(struct ti_adc_data *data,
78 struct iio_chan_spec const *chan, int *val)
79 {
80 int ret;
81
82 switch (data->read_size) {
83 case 2: {
84 __be16 buf;
85
86 ret = spi_read(data->spi, (void *) &buf, 2);
87 if (ret)
88 return ret;
89
90 *val = be16_to_cpu(buf);
91 break;
92 }
93 case 3: {
94 __be32 buf;
95
96 ret = spi_read(data->spi, (void *) &buf, 3);
97 if (ret)
98 return ret;
99
100 *val = be32_to_cpu(buf) >> 8;
101 break;
102 }
103 default:
104 return -EINVAL;
105 }
106
107 *val = sign_extend32(*val >> data->shift, chan->scan_type.realbits - 1);
108
109 return 0;
110 }
111
ti_adc_trigger_handler(int irq,void * private)112 static irqreturn_t ti_adc_trigger_handler(int irq, void *private)
113 {
114 struct iio_poll_func *pf = private;
115 struct iio_dev *indio_dev = pf->indio_dev;
116 struct ti_adc_data *data = iio_priv(indio_dev);
117 int ret;
118
119 ret = ti_adc_read_measurement(data, &indio_dev->channels[0],
120 (int *) &data->buffer);
121 if (!ret)
122 iio_push_to_buffers_with_timestamp(indio_dev,
123 data->buffer,
124 iio_get_time_ns(indio_dev));
125
126 iio_trigger_notify_done(indio_dev->trig);
127
128 return IRQ_HANDLED;
129 }
130
ti_adc_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)131 static int ti_adc_read_raw(struct iio_dev *indio_dev,
132 struct iio_chan_spec const *chan,
133 int *val, int *val2, long mask)
134 {
135 struct ti_adc_data *data = iio_priv(indio_dev);
136 int ret;
137
138 switch (mask) {
139 case IIO_CHAN_INFO_RAW:
140 ret = iio_device_claim_direct_mode(indio_dev);
141 if (ret)
142 return ret;
143
144 ret = ti_adc_read_measurement(data, chan, val);
145 iio_device_release_direct_mode(indio_dev);
146
147 if (ret)
148 return ret;
149
150 return IIO_VAL_INT;
151 case IIO_CHAN_INFO_SCALE:
152 ret = regulator_get_voltage(data->ref);
153 if (ret < 0)
154 return ret;
155
156 *val = ret / 1000;
157 *val2 = chan->scan_type.realbits;
158
159 return IIO_VAL_FRACTIONAL_LOG2;
160 case IIO_CHAN_INFO_OFFSET:
161 *val = 1 << (chan->scan_type.realbits - 1);
162 return IIO_VAL_INT;
163 }
164
165 return 0;
166 }
167
168 static const struct iio_info ti_adc_info = {
169 .read_raw = ti_adc_read_raw,
170 };
171
ti_adc_reg_disable(void * reg)172 static void ti_adc_reg_disable(void *reg)
173 {
174 regulator_disable(reg);
175 }
176
ti_adc_probe(struct spi_device * spi)177 static int ti_adc_probe(struct spi_device *spi)
178 {
179 struct iio_dev *indio_dev;
180 struct ti_adc_data *data;
181 int ret;
182
183 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*data));
184 if (!indio_dev)
185 return -ENOMEM;
186
187 indio_dev->info = &ti_adc_info;
188 indio_dev->name = TI_ADC_DRV_NAME;
189 indio_dev->modes = INDIO_DIRECT_MODE;
190
191 data = iio_priv(indio_dev);
192 data->spi = spi;
193
194 switch (spi_get_device_id(spi)->driver_data) {
195 case TI_ADC141S626:
196 indio_dev->channels = ti_adc141s626_channels;
197 indio_dev->num_channels = ARRAY_SIZE(ti_adc141s626_channels);
198 data->shift = 0;
199 data->read_size = 2;
200 break;
201 case TI_ADC161S626:
202 indio_dev->channels = ti_adc161s626_channels;
203 indio_dev->num_channels = ARRAY_SIZE(ti_adc161s626_channels);
204 data->shift = 6;
205 data->read_size = 3;
206 break;
207 }
208
209 data->ref = devm_regulator_get(&spi->dev, "vdda");
210 if (IS_ERR(data->ref))
211 return PTR_ERR(data->ref);
212
213 ret = regulator_enable(data->ref);
214 if (ret < 0)
215 return ret;
216
217 ret = devm_add_action_or_reset(&spi->dev, ti_adc_reg_disable,
218 data->ref);
219 if (ret)
220 return ret;
221
222 ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, NULL,
223 ti_adc_trigger_handler, NULL);
224 if (ret)
225 return ret;
226
227 return devm_iio_device_register(&spi->dev, indio_dev);
228 }
229
230 static const struct of_device_id ti_adc_dt_ids[] = {
231 { .compatible = "ti,adc141s626", },
232 { .compatible = "ti,adc161s626", },
233 {}
234 };
235 MODULE_DEVICE_TABLE(of, ti_adc_dt_ids);
236
237 static const struct spi_device_id ti_adc_id[] = {
238 {"adc141s626", TI_ADC141S626},
239 {"adc161s626", TI_ADC161S626},
240 {},
241 };
242 MODULE_DEVICE_TABLE(spi, ti_adc_id);
243
244 static struct spi_driver ti_adc_driver = {
245 .driver = {
246 .name = TI_ADC_DRV_NAME,
247 .of_match_table = ti_adc_dt_ids,
248 },
249 .probe = ti_adc_probe,
250 .id_table = ti_adc_id,
251 };
252 module_spi_driver(ti_adc_driver);
253
254 MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
255 MODULE_DESCRIPTION("Texas Instruments ADC1x1S 1-channel differential ADC");
256 MODULE_LICENSE("GPL");
257