1/*
2 * AD7298 SPI ADC driver
3 *
4 * Copyright 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/delay.h>
17#include <linux/module.h>
18
19#include "../iio.h"
20#include "../sysfs.h"
21#include "../buffer.h"
22
23#include "ad7298.h"
24
25static struct iio_chan_spec ad7298_channels[] = {
26	IIO_CHAN(IIO_TEMP, 0, 1, 0, NULL, 0, 0,
27		 IIO_CHAN_INFO_SCALE_SEPARATE_BIT,
28		 9, AD7298_CH_TEMP, IIO_ST('s', 32, 32, 0), 0),
29	IIO_CHAN(IIO_VOLTAGE, 0, 1, 0, NULL, 0, 0,
30		 IIO_CHAN_INFO_SCALE_SHARED_BIT,
31		 0, 0, IIO_ST('u', 12, 16, 0), 0),
32	IIO_CHAN(IIO_VOLTAGE, 0, 1, 0, NULL, 1, 0,
33		 IIO_CHAN_INFO_SCALE_SHARED_BIT,
34		 1, 1, IIO_ST('u', 12, 16, 0), 0),
35	IIO_CHAN(IIO_VOLTAGE, 0, 1, 0, NULL, 2, 0,
36		 IIO_CHAN_INFO_SCALE_SHARED_BIT,
37		 2, 2, IIO_ST('u', 12, 16, 0), 0),
38	IIO_CHAN(IIO_VOLTAGE, 0, 1, 0, NULL, 3, 0,
39		 IIO_CHAN_INFO_SCALE_SHARED_BIT,
40		 3, 3, IIO_ST('u', 12, 16, 0), 0),
41	IIO_CHAN(IIO_VOLTAGE, 0, 1, 0, NULL, 4, 0,
42		 IIO_CHAN_INFO_SCALE_SHARED_BIT,
43		 4, 4, IIO_ST('u', 12, 16, 0), 0),
44	IIO_CHAN(IIO_VOLTAGE, 0, 1, 0, NULL, 5, 0,
45		 IIO_CHAN_INFO_SCALE_SHARED_BIT,
46		 5, 5, IIO_ST('u', 12, 16, 0), 0),
47	IIO_CHAN(IIO_VOLTAGE, 0, 1, 0, NULL, 6, 0,
48		 IIO_CHAN_INFO_SCALE_SHARED_BIT,
49		 6, 6, IIO_ST('u', 12, 16, 0), 0),
50	IIO_CHAN(IIO_VOLTAGE, 0, 1, 0, NULL, 7, 0,
51		 IIO_CHAN_INFO_SCALE_SHARED_BIT,
52		 7, 7, IIO_ST('u', 12, 16, 0), 0),
53	IIO_CHAN_SOFT_TIMESTAMP(8),
54};
55
56static int ad7298_scan_direct(struct ad7298_state *st, unsigned ch)
57{
58	int ret;
59	st->tx_buf[0] = cpu_to_be16(AD7298_WRITE | st->ext_ref |
60				   (AD7298_CH(0) >> ch));
61
62	ret = spi_sync(st->spi, &st->scan_single_msg);
63	if (ret)
64		return ret;
65
66	return be16_to_cpu(st->rx_buf[0]);
67}
68
69static int ad7298_scan_temp(struct ad7298_state *st, int *val)
70{
71	int tmp, ret;
72	__be16 buf;
73
74	buf = cpu_to_be16(AD7298_WRITE | AD7298_TSENSE |
75			  AD7298_TAVG | st->ext_ref);
76
77	ret = spi_write(st->spi, (u8 *)&buf, 2);
78	if (ret)
79		return ret;
80
81	buf = cpu_to_be16(0);
82
83	ret = spi_write(st->spi, (u8 *)&buf, 2);
84	if (ret)
85		return ret;
86
87	usleep_range(101, 1000); /* sleep > 100us */
88
89	ret = spi_read(st->spi, (u8 *)&buf, 2);
90	if (ret)
91		return ret;
92
93	tmp = be16_to_cpu(buf) & RES_MASK(AD7298_BITS);
94
95	/*
96	 * One LSB of the ADC corresponds to 0.25 deg C.
97	 * The temperature reading is in 12-bit twos complement format
98	 */
99
100	if (tmp & (1 << (AD7298_BITS - 1))) {
101		tmp = (4096 - tmp) * 250;
102		tmp -= (2 * tmp);
103
104	} else {
105		tmp *= 250; /* temperature in milli degrees Celsius */
106	}
107
108	*val = tmp;
109
110	return 0;
111}
112
113static int ad7298_read_raw(struct iio_dev *indio_dev,
114			   struct iio_chan_spec const *chan,
115			   int *val,
116			   int *val2,
117			   long m)
118{
119	int ret;
120	struct ad7298_state *st = iio_priv(indio_dev);
121	unsigned int scale_uv;
122
123	switch (m) {
124	case 0:
125		mutex_lock(&indio_dev->mlock);
126		if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
127			ret = -EBUSY;
128		} else {
129			if (chan->address == AD7298_CH_TEMP)
130				ret = ad7298_scan_temp(st, val);
131			else
132				ret = ad7298_scan_direct(st, chan->address);
133		}
134		mutex_unlock(&indio_dev->mlock);
135
136		if (ret < 0)
137			return ret;
138
139		if (chan->address != AD7298_CH_TEMP)
140			*val = ret & RES_MASK(AD7298_BITS);
141
142		return IIO_VAL_INT;
143	case IIO_CHAN_INFO_SCALE:
144		switch (chan->type) {
145		case IIO_VOLTAGE:
146			scale_uv = (st->int_vref_mv * 1000) >> AD7298_BITS;
147			*val =  scale_uv / 1000;
148			*val2 = (scale_uv % 1000) * 1000;
149			return IIO_VAL_INT_PLUS_MICRO;
150		case IIO_TEMP:
151			*val =  1;
152			*val2 = 0;
153			return IIO_VAL_INT_PLUS_MICRO;
154		default:
155			return -EINVAL;
156		}
157	}
158	return -EINVAL;
159}
160
161static const struct iio_info ad7298_info = {
162	.read_raw = &ad7298_read_raw,
163	.driver_module = THIS_MODULE,
164};
165
166static int __devinit ad7298_probe(struct spi_device *spi)
167{
168	struct ad7298_platform_data *pdata = spi->dev.platform_data;
169	struct ad7298_state *st;
170	int ret;
171	struct iio_dev *indio_dev = iio_allocate_device(sizeof(*st));
172
173	if (indio_dev == NULL)
174		return -ENOMEM;
175
176	st = iio_priv(indio_dev);
177
178	st->reg = regulator_get(&spi->dev, "vcc");
179	if (!IS_ERR(st->reg)) {
180		ret = regulator_enable(st->reg);
181		if (ret)
182			goto error_put_reg;
183	}
184
185	spi_set_drvdata(spi, indio_dev);
186
187	st->spi = spi;
188
189	indio_dev->name = spi_get_device_id(spi)->name;
190	indio_dev->dev.parent = &spi->dev;
191	indio_dev->modes = INDIO_DIRECT_MODE;
192	indio_dev->channels = ad7298_channels;
193	indio_dev->num_channels = ARRAY_SIZE(ad7298_channels);
194	indio_dev->info = &ad7298_info;
195
196	/* Setup default message */
197
198	st->scan_single_xfer[0].tx_buf = &st->tx_buf[0];
199	st->scan_single_xfer[0].len = 2;
200	st->scan_single_xfer[0].cs_change = 1;
201	st->scan_single_xfer[1].tx_buf = &st->tx_buf[1];
202	st->scan_single_xfer[1].len = 2;
203	st->scan_single_xfer[1].cs_change = 1;
204	st->scan_single_xfer[2].rx_buf = &st->rx_buf[0];
205	st->scan_single_xfer[2].len = 2;
206
207	spi_message_init(&st->scan_single_msg);
208	spi_message_add_tail(&st->scan_single_xfer[0], &st->scan_single_msg);
209	spi_message_add_tail(&st->scan_single_xfer[1], &st->scan_single_msg);
210	spi_message_add_tail(&st->scan_single_xfer[2], &st->scan_single_msg);
211
212	if (pdata && pdata->vref_mv) {
213		st->int_vref_mv = pdata->vref_mv;
214		st->ext_ref = AD7298_EXTREF;
215	} else {
216		st->int_vref_mv = AD7298_INTREF_mV;
217	}
218
219	ret = ad7298_register_ring_funcs_and_init(indio_dev);
220	if (ret)
221		goto error_disable_reg;
222
223	ret = iio_buffer_register(indio_dev,
224				  &ad7298_channels[1], /* skip temp0 */
225				  ARRAY_SIZE(ad7298_channels) - 1);
226	if (ret)
227		goto error_cleanup_ring;
228	ret = iio_device_register(indio_dev);
229	if (ret)
230		goto error_unregister_ring;
231
232	return 0;
233
234error_unregister_ring:
235	iio_buffer_unregister(indio_dev);
236error_cleanup_ring:
237	ad7298_ring_cleanup(indio_dev);
238error_disable_reg:
239	if (!IS_ERR(st->reg))
240		regulator_disable(st->reg);
241error_put_reg:
242	if (!IS_ERR(st->reg))
243		regulator_put(st->reg);
244	iio_free_device(indio_dev);
245
246	return ret;
247}
248
249static int __devexit ad7298_remove(struct spi_device *spi)
250{
251	struct iio_dev *indio_dev = spi_get_drvdata(spi);
252	struct ad7298_state *st = iio_priv(indio_dev);
253
254	iio_device_unregister(indio_dev);
255	iio_buffer_unregister(indio_dev);
256	ad7298_ring_cleanup(indio_dev);
257	if (!IS_ERR(st->reg)) {
258		regulator_disable(st->reg);
259		regulator_put(st->reg);
260	}
261	iio_free_device(indio_dev);
262
263	return 0;
264}
265
266static const struct spi_device_id ad7298_id[] = {
267	{"ad7298", 0},
268	{}
269};
270MODULE_DEVICE_TABLE(spi, ad7298_id);
271
272static struct spi_driver ad7298_driver = {
273	.driver = {
274		.name	= "ad7298",
275		.owner	= THIS_MODULE,
276	},
277	.probe		= ad7298_probe,
278	.remove		= __devexit_p(ad7298_remove),
279	.id_table	= ad7298_id,
280};
281module_spi_driver(ad7298_driver);
282
283MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
284MODULE_DESCRIPTION("Analog Devices AD7298 ADC");
285MODULE_LICENSE("GPL v2");
286