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
27enum {
28	TI_ADC141S626,
29	TI_ADC161S626,
30};
31
32static 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
49static 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
66struct 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
77static 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
112static 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
131static 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
168static const struct iio_info ti_adc_info = {
169	.read_raw = ti_adc_read_raw,
170};
171
172static void ti_adc_reg_disable(void *reg)
173{
174	regulator_disable(reg);
175}
176
177static 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
230static const struct of_device_id ti_adc_dt_ids[] = {
231	{ .compatible = "ti,adc141s626", },
232	{ .compatible = "ti,adc161s626", },
233	{}
234};
235MODULE_DEVICE_TABLE(of, ti_adc_dt_ids);
236
237static const struct spi_device_id ti_adc_id[] = {
238	{"adc141s626", TI_ADC141S626},
239	{"adc161s626", TI_ADC161S626},
240	{},
241};
242MODULE_DEVICE_TABLE(spi, ti_adc_id);
243
244static 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};
252module_spi_driver(ti_adc_driver);
253
254MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
255MODULE_DESCRIPTION("Texas Instruments ADC1x1S 1-channel differential ADC");
256MODULE_LICENSE("GPL");
257