1/*
2 * AD7887 SPI ADC driver
3 *
4 * Copyright 2010-2011 Analog Devices Inc.
5 *
6 * Licensed under the GPL-2.
7 */
8
9#include <linux/device.h>
10#include <linux/kernel.h>
11#include <linux/slab.h>
12#include <linux/sysfs.h>
13#include <linux/spi/spi.h>
14#include <linux/regulator/consumer.h>
15#include <linux/err.h>
16#include <linux/module.h>
17
18#include "../iio.h"
19#include "../sysfs.h"
20#include "../buffer.h"
21
22
23#include "ad7887.h"
24
25static int ad7887_scan_direct(struct ad7887_state *st, unsigned ch)
26{
27	int ret = spi_sync(st->spi, &st->msg[ch]);
28	if (ret)
29		return ret;
30
31	return (st->data[(ch * 2)] << 8) | st->data[(ch * 2) + 1];
32}
33
34static int ad7887_read_raw(struct iio_dev *indio_dev,
35			   struct iio_chan_spec const *chan,
36			   int *val,
37			   int *val2,
38			   long m)
39{
40	int ret;
41	struct ad7887_state *st = iio_priv(indio_dev);
42	unsigned int scale_uv;
43
44	switch (m) {
45	case 0:
46		mutex_lock(&indio_dev->mlock);
47		if (iio_buffer_enabled(indio_dev))
48			ret = -EBUSY;
49		else
50			ret = ad7887_scan_direct(st, chan->address);
51		mutex_unlock(&indio_dev->mlock);
52
53		if (ret < 0)
54			return ret;
55		*val = (ret >> st->chip_info->channel[0].scan_type.shift) &
56			RES_MASK(st->chip_info->channel[0].scan_type.realbits);
57		return IIO_VAL_INT;
58	case IIO_CHAN_INFO_SCALE:
59		scale_uv = (st->int_vref_mv * 1000)
60			>> st->chip_info->channel[0].scan_type.realbits;
61		*val =  scale_uv/1000;
62		*val2 = (scale_uv%1000)*1000;
63		return IIO_VAL_INT_PLUS_MICRO;
64	}
65	return -EINVAL;
66}
67
68
69static const struct ad7887_chip_info ad7887_chip_info_tbl[] = {
70	/*
71	 * More devices added in future
72	 */
73	[ID_AD7887] = {
74		.channel[0] = {
75			.type = IIO_VOLTAGE,
76			.indexed = 1,
77			.channel = 1,
78			.info_mask = IIO_CHAN_INFO_SCALE_SHARED_BIT,
79			.address = 1,
80			.scan_index = 1,
81			.scan_type = IIO_ST('u', 12, 16, 0),
82		},
83		.channel[1] = {
84			.type = IIO_VOLTAGE,
85			.indexed = 1,
86			.channel = 0,
87			.info_mask = IIO_CHAN_INFO_SCALE_SHARED_BIT,
88			.address = 0,
89			.scan_index = 0,
90			.scan_type = IIO_ST('u', 12, 16, 0),
91		},
92		.channel[2] = IIO_CHAN_SOFT_TIMESTAMP(2),
93		.int_vref_mv = 2500,
94	},
95};
96
97static const struct iio_info ad7887_info = {
98	.read_raw = &ad7887_read_raw,
99	.driver_module = THIS_MODULE,
100};
101
102static int __devinit ad7887_probe(struct spi_device *spi)
103{
104	struct ad7887_platform_data *pdata = spi->dev.platform_data;
105	struct ad7887_state *st;
106	int ret, voltage_uv = 0;
107	struct iio_dev *indio_dev = iio_allocate_device(sizeof(*st));
108
109	if (indio_dev == NULL)
110		return -ENOMEM;
111
112	st = iio_priv(indio_dev);
113
114	st->reg = regulator_get(&spi->dev, "vcc");
115	if (!IS_ERR(st->reg)) {
116		ret = regulator_enable(st->reg);
117		if (ret)
118			goto error_put_reg;
119
120		voltage_uv = regulator_get_voltage(st->reg);
121	}
122
123	st->chip_info =
124		&ad7887_chip_info_tbl[spi_get_device_id(spi)->driver_data];
125
126	spi_set_drvdata(spi, indio_dev);
127	st->spi = spi;
128
129	/* Estabilish that the iio_dev is a child of the spi device */
130	indio_dev->dev.parent = &spi->dev;
131	indio_dev->name = spi_get_device_id(spi)->name;
132	indio_dev->info = &ad7887_info;
133	indio_dev->modes = INDIO_DIRECT_MODE;
134
135	/* Setup default message */
136
137	st->tx_cmd_buf[0] = AD7887_CH_AIN0 | AD7887_PM_MODE4 |
138			    ((pdata && pdata->use_onchip_ref) ?
139			    0 : AD7887_REF_DIS);
140
141	st->xfer[0].rx_buf = &st->data[0];
142	st->xfer[0].tx_buf = &st->tx_cmd_buf[0];
143	st->xfer[0].len = 2;
144
145	spi_message_init(&st->msg[AD7887_CH0]);
146	spi_message_add_tail(&st->xfer[0], &st->msg[AD7887_CH0]);
147
148	if (pdata && pdata->en_dual) {
149		st->tx_cmd_buf[0] |= AD7887_DUAL | AD7887_REF_DIS;
150
151		st->tx_cmd_buf[2] = AD7887_CH_AIN1 | AD7887_DUAL |
152				    AD7887_REF_DIS | AD7887_PM_MODE4;
153		st->tx_cmd_buf[4] = AD7887_CH_AIN0 | AD7887_DUAL |
154				    AD7887_REF_DIS | AD7887_PM_MODE4;
155		st->tx_cmd_buf[6] = AD7887_CH_AIN1 | AD7887_DUAL |
156				    AD7887_REF_DIS | AD7887_PM_MODE4;
157
158		st->xfer[1].rx_buf = &st->data[0];
159		st->xfer[1].tx_buf = &st->tx_cmd_buf[2];
160		st->xfer[1].len = 2;
161
162		st->xfer[2].rx_buf = &st->data[2];
163		st->xfer[2].tx_buf = &st->tx_cmd_buf[4];
164		st->xfer[2].len = 2;
165
166		spi_message_init(&st->msg[AD7887_CH0_CH1]);
167		spi_message_add_tail(&st->xfer[1], &st->msg[AD7887_CH0_CH1]);
168		spi_message_add_tail(&st->xfer[2], &st->msg[AD7887_CH0_CH1]);
169
170		st->xfer[3].rx_buf = &st->data[0];
171		st->xfer[3].tx_buf = &st->tx_cmd_buf[6];
172		st->xfer[3].len = 2;
173
174		spi_message_init(&st->msg[AD7887_CH1]);
175		spi_message_add_tail(&st->xfer[3], &st->msg[AD7887_CH1]);
176
177		if (pdata && pdata->vref_mv)
178			st->int_vref_mv = pdata->vref_mv;
179		else if (voltage_uv)
180			st->int_vref_mv = voltage_uv / 1000;
181		else
182			dev_warn(&spi->dev, "reference voltage unspecified\n");
183
184		indio_dev->channels = st->chip_info->channel;
185		indio_dev->num_channels = 3;
186	} else {
187		if (pdata && pdata->vref_mv)
188			st->int_vref_mv = pdata->vref_mv;
189		else if (pdata && pdata->use_onchip_ref)
190			st->int_vref_mv = st->chip_info->int_vref_mv;
191		else
192			dev_warn(&spi->dev, "reference voltage unspecified\n");
193
194		indio_dev->channels = &st->chip_info->channel[1];
195		indio_dev->num_channels = 2;
196	}
197
198	ret = ad7887_register_ring_funcs_and_init(indio_dev);
199	if (ret)
200		goto error_disable_reg;
201
202	ret = iio_buffer_register(indio_dev,
203				  indio_dev->channels,
204				  indio_dev->num_channels);
205	if (ret)
206		goto error_cleanup_ring;
207
208	ret = iio_device_register(indio_dev);
209	if (ret)
210		goto error_unregister_ring;
211
212	return 0;
213error_unregister_ring:
214	iio_buffer_unregister(indio_dev);
215error_cleanup_ring:
216	ad7887_ring_cleanup(indio_dev);
217error_disable_reg:
218	if (!IS_ERR(st->reg))
219		regulator_disable(st->reg);
220error_put_reg:
221	if (!IS_ERR(st->reg))
222		regulator_put(st->reg);
223	iio_free_device(indio_dev);
224
225	return ret;
226}
227
228static int ad7887_remove(struct spi_device *spi)
229{
230	struct iio_dev *indio_dev = spi_get_drvdata(spi);
231	struct ad7887_state *st = iio_priv(indio_dev);
232
233	iio_device_unregister(indio_dev);
234	iio_buffer_unregister(indio_dev);
235	ad7887_ring_cleanup(indio_dev);
236	if (!IS_ERR(st->reg)) {
237		regulator_disable(st->reg);
238		regulator_put(st->reg);
239	}
240	iio_free_device(indio_dev);
241
242	return 0;
243}
244
245static const struct spi_device_id ad7887_id[] = {
246	{"ad7887", ID_AD7887},
247	{}
248};
249MODULE_DEVICE_TABLE(spi, ad7887_id);
250
251static struct spi_driver ad7887_driver = {
252	.driver = {
253		.name	= "ad7887",
254		.owner	= THIS_MODULE,
255	},
256	.probe		= ad7887_probe,
257	.remove		= __devexit_p(ad7887_remove),
258	.id_table	= ad7887_id,
259};
260module_spi_driver(ad7887_driver);
261
262MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
263MODULE_DESCRIPTION("Analog Devices AD7887 ADC");
264MODULE_LICENSE("GPL v2");
265