1/*
2 * AD5686R, AD5685R, AD5684R Digital to analog converters  driver
3 *
4 * Copyright 2011 Analog Devices Inc.
5 *
6 * Licensed under the GPL-2.
7 */
8
9#include <linux/interrupt.h>
10#include <linux/fs.h>
11#include <linux/device.h>
12#include <linux/module.h>
13#include <linux/kernel.h>
14#include <linux/spi/spi.h>
15#include <linux/slab.h>
16#include <linux/sysfs.h>
17#include <linux/regulator/consumer.h>
18
19#include <linux/iio/iio.h>
20#include <linux/iio/sysfs.h>
21
22#define AD5686_DAC_CHANNELS			4
23
24#define AD5686_ADDR(x)				((x) << 16)
25#define AD5686_CMD(x)				((x) << 20)
26
27#define AD5686_ADDR_DAC(chan)		(0x1 << (chan))
28#define AD5686_ADDR_ALL_DAC			0xF
29
30#define AD5686_CMD_NOOP				0x0
31#define AD5686_CMD_WRITE_INPUT_N		0x1
32#define AD5686_CMD_UPDATE_DAC_N			0x2
33#define AD5686_CMD_WRITE_INPUT_N_UPDATE_N	0x3
34#define AD5686_CMD_POWERDOWN_DAC		0x4
35#define AD5686_CMD_LDAC_MASK			0x5
36#define AD5686_CMD_RESET			0x6
37#define AD5686_CMD_INTERNAL_REFER_SETUP		0x7
38#define AD5686_CMD_DAISY_CHAIN_ENABLE		0x8
39#define AD5686_CMD_READBACK_ENABLE		0x9
40
41#define AD5686_LDAC_PWRDN_NONE			0x0
42#define AD5686_LDAC_PWRDN_1K			0x1
43#define AD5686_LDAC_PWRDN_100K			0x2
44#define AD5686_LDAC_PWRDN_3STATE		0x3
45
46/**
47 * struct ad5686_chip_info - chip specific information
48 * @int_vref_mv:	AD5620/40/60: the internal reference voltage
49 * @channel:		channel specification
50*/
51
52struct ad5686_chip_info {
53	u16				int_vref_mv;
54	struct iio_chan_spec		channel[AD5686_DAC_CHANNELS];
55};
56
57/**
58 * struct ad5446_state - driver instance specific data
59 * @spi:		spi_device
60 * @chip_info:		chip model specific constants, available modes etc
61 * @reg:		supply regulator
62 * @vref_mv:		actual reference voltage used
63 * @pwr_down_mask:	power down mask
64 * @pwr_down_mode:	current power down mode
65 * @data:		spi transfer buffers
66 */
67
68struct ad5686_state {
69	struct spi_device		*spi;
70	const struct ad5686_chip_info	*chip_info;
71	struct regulator		*reg;
72	unsigned short			vref_mv;
73	unsigned			pwr_down_mask;
74	unsigned			pwr_down_mode;
75	/*
76	 * DMA (thus cache coherency maintenance) requires the
77	 * transfer buffers to live in their own cache lines.
78	 */
79
80	union {
81		__be32 d32;
82		u8 d8[4];
83	} data[3] ____cacheline_aligned;
84};
85
86/**
87 * ad5686_supported_device_ids:
88 */
89
90enum ad5686_supported_device_ids {
91	ID_AD5684,
92	ID_AD5685,
93	ID_AD5686,
94};
95static int ad5686_spi_write(struct ad5686_state *st,
96			     u8 cmd, u8 addr, u16 val, u8 shift)
97{
98	val <<= shift;
99
100	st->data[0].d32 = cpu_to_be32(AD5686_CMD(cmd) |
101			      AD5686_ADDR(addr) |
102			      val);
103
104	return spi_write(st->spi, &st->data[0].d8[1], 3);
105}
106
107static int ad5686_spi_read(struct ad5686_state *st, u8 addr)
108{
109	struct spi_transfer t[] = {
110		{
111			.tx_buf = &st->data[0].d8[1],
112			.len = 3,
113			.cs_change = 1,
114		}, {
115			.tx_buf = &st->data[1].d8[1],
116			.rx_buf = &st->data[2].d8[1],
117			.len = 3,
118		},
119	};
120	int ret;
121
122	st->data[0].d32 = cpu_to_be32(AD5686_CMD(AD5686_CMD_READBACK_ENABLE) |
123			      AD5686_ADDR(addr));
124	st->data[1].d32 = cpu_to_be32(AD5686_CMD(AD5686_CMD_NOOP));
125
126	ret = spi_sync_transfer(st->spi, t, ARRAY_SIZE(t));
127	if (ret < 0)
128		return ret;
129
130	return be32_to_cpu(st->data[2].d32);
131}
132
133static const char * const ad5686_powerdown_modes[] = {
134	"1kohm_to_gnd",
135	"100kohm_to_gnd",
136	"three_state"
137};
138
139static int ad5686_get_powerdown_mode(struct iio_dev *indio_dev,
140	const struct iio_chan_spec *chan)
141{
142	struct ad5686_state *st = iio_priv(indio_dev);
143
144	return ((st->pwr_down_mode >> (chan->channel * 2)) & 0x3) - 1;
145}
146
147static int ad5686_set_powerdown_mode(struct iio_dev *indio_dev,
148	const struct iio_chan_spec *chan, unsigned int mode)
149{
150	struct ad5686_state *st = iio_priv(indio_dev);
151
152	st->pwr_down_mode &= ~(0x3 << (chan->channel * 2));
153	st->pwr_down_mode |= ((mode + 1) << (chan->channel * 2));
154
155	return 0;
156}
157
158static const struct iio_enum ad5686_powerdown_mode_enum = {
159	.items = ad5686_powerdown_modes,
160	.num_items = ARRAY_SIZE(ad5686_powerdown_modes),
161	.get = ad5686_get_powerdown_mode,
162	.set = ad5686_set_powerdown_mode,
163};
164
165static ssize_t ad5686_read_dac_powerdown(struct iio_dev *indio_dev,
166	uintptr_t private, const struct iio_chan_spec *chan, char *buf)
167{
168	struct ad5686_state *st = iio_priv(indio_dev);
169
170	return sprintf(buf, "%d\n", !!(st->pwr_down_mask &
171			(0x3 << (chan->channel * 2))));
172}
173
174static ssize_t ad5686_write_dac_powerdown(struct iio_dev *indio_dev,
175	 uintptr_t private, const struct iio_chan_spec *chan, const char *buf,
176	 size_t len)
177{
178	bool readin;
179	int ret;
180	struct ad5686_state *st = iio_priv(indio_dev);
181
182	ret = strtobool(buf, &readin);
183	if (ret)
184		return ret;
185
186	if (readin)
187		st->pwr_down_mask |= (0x3 << (chan->channel * 2));
188	else
189		st->pwr_down_mask &= ~(0x3 << (chan->channel * 2));
190
191	ret = ad5686_spi_write(st, AD5686_CMD_POWERDOWN_DAC, 0,
192			       st->pwr_down_mask & st->pwr_down_mode, 0);
193
194	return ret ? ret : len;
195}
196
197static int ad5686_read_raw(struct iio_dev *indio_dev,
198			   struct iio_chan_spec const *chan,
199			   int *val,
200			   int *val2,
201			   long m)
202{
203	struct ad5686_state *st = iio_priv(indio_dev);
204	int ret;
205
206	switch (m) {
207	case IIO_CHAN_INFO_RAW:
208		mutex_lock(&indio_dev->mlock);
209		ret = ad5686_spi_read(st, chan->address);
210		mutex_unlock(&indio_dev->mlock);
211		if (ret < 0)
212			return ret;
213		*val = ret;
214		return IIO_VAL_INT;
215	case IIO_CHAN_INFO_SCALE:
216		*val = st->vref_mv;
217		*val2 = chan->scan_type.realbits;
218		return IIO_VAL_FRACTIONAL_LOG2;
219	}
220	return -EINVAL;
221}
222
223static int ad5686_write_raw(struct iio_dev *indio_dev,
224			       struct iio_chan_spec const *chan,
225			       int val,
226			       int val2,
227			       long mask)
228{
229	struct ad5686_state *st = iio_priv(indio_dev);
230	int ret;
231
232	switch (mask) {
233	case IIO_CHAN_INFO_RAW:
234		if (val > (1 << chan->scan_type.realbits) || val < 0)
235			return -EINVAL;
236
237		mutex_lock(&indio_dev->mlock);
238		ret = ad5686_spi_write(st,
239				 AD5686_CMD_WRITE_INPUT_N_UPDATE_N,
240				 chan->address,
241				 val,
242				 chan->scan_type.shift);
243		mutex_unlock(&indio_dev->mlock);
244		break;
245	default:
246		ret = -EINVAL;
247	}
248
249	return ret;
250}
251
252static const struct iio_info ad5686_info = {
253	.read_raw = ad5686_read_raw,
254	.write_raw = ad5686_write_raw,
255	.driver_module = THIS_MODULE,
256};
257
258static const struct iio_chan_spec_ext_info ad5686_ext_info[] = {
259	{
260		.name = "powerdown",
261		.read = ad5686_read_dac_powerdown,
262		.write = ad5686_write_dac_powerdown,
263		.shared = IIO_SEPARATE,
264	},
265	IIO_ENUM("powerdown_mode", IIO_SEPARATE, &ad5686_powerdown_mode_enum),
266	IIO_ENUM_AVAILABLE("powerdown_mode", &ad5686_powerdown_mode_enum),
267	{ },
268};
269
270#define AD5868_CHANNEL(chan, bits, _shift) {			\
271		.type = IIO_VOLTAGE,				\
272		.indexed = 1,					\
273		.output = 1,					\
274		.channel = chan,				\
275		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
276		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),\
277		.address = AD5686_ADDR_DAC(chan),		\
278		.scan_type = {					\
279			.sign = 'u',				\
280			.realbits = (bits),			\
281			.storagebits = 16,			\
282			.shift = (_shift),			\
283		},						\
284		.ext_info = ad5686_ext_info,			\
285}
286
287static const struct ad5686_chip_info ad5686_chip_info_tbl[] = {
288	[ID_AD5684] = {
289		.channel[0] = AD5868_CHANNEL(0, 12, 4),
290		.channel[1] = AD5868_CHANNEL(1, 12, 4),
291		.channel[2] = AD5868_CHANNEL(2, 12, 4),
292		.channel[3] = AD5868_CHANNEL(3, 12, 4),
293		.int_vref_mv = 2500,
294	},
295	[ID_AD5685] = {
296		.channel[0] = AD5868_CHANNEL(0, 14, 2),
297		.channel[1] = AD5868_CHANNEL(1, 14, 2),
298		.channel[2] = AD5868_CHANNEL(2, 14, 2),
299		.channel[3] = AD5868_CHANNEL(3, 14, 2),
300		.int_vref_mv = 2500,
301	},
302	[ID_AD5686] = {
303		.channel[0] = AD5868_CHANNEL(0, 16, 0),
304		.channel[1] = AD5868_CHANNEL(1, 16, 0),
305		.channel[2] = AD5868_CHANNEL(2, 16, 0),
306		.channel[3] = AD5868_CHANNEL(3, 16, 0),
307		.int_vref_mv = 2500,
308	},
309};
310
311
312static int ad5686_probe(struct spi_device *spi)
313{
314	struct ad5686_state *st;
315	struct iio_dev *indio_dev;
316	int ret, voltage_uv = 0;
317
318	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
319	if (indio_dev == NULL)
320		return  -ENOMEM;
321
322	st = iio_priv(indio_dev);
323	spi_set_drvdata(spi, indio_dev);
324
325	st->reg = devm_regulator_get_optional(&spi->dev, "vcc");
326	if (!IS_ERR(st->reg)) {
327		ret = regulator_enable(st->reg);
328		if (ret)
329			return ret;
330
331		ret = regulator_get_voltage(st->reg);
332		if (ret < 0)
333			goto error_disable_reg;
334
335		voltage_uv = ret;
336	}
337
338	st->chip_info =
339		&ad5686_chip_info_tbl[spi_get_device_id(spi)->driver_data];
340
341	if (voltage_uv)
342		st->vref_mv = voltage_uv / 1000;
343	else
344		st->vref_mv = st->chip_info->int_vref_mv;
345
346	st->spi = spi;
347
348	/* Set all the power down mode for all channels to 1K pulldown */
349	st->pwr_down_mode = 0x55;
350
351	indio_dev->dev.parent = &spi->dev;
352	indio_dev->name = spi_get_device_id(spi)->name;
353	indio_dev->info = &ad5686_info;
354	indio_dev->modes = INDIO_DIRECT_MODE;
355	indio_dev->channels = st->chip_info->channel;
356	indio_dev->num_channels = AD5686_DAC_CHANNELS;
357
358	ret = ad5686_spi_write(st, AD5686_CMD_INTERNAL_REFER_SETUP, 0,
359				!!voltage_uv, 0);
360	if (ret)
361		goto error_disable_reg;
362
363	ret = iio_device_register(indio_dev);
364	if (ret)
365		goto error_disable_reg;
366
367	return 0;
368
369error_disable_reg:
370	if (!IS_ERR(st->reg))
371		regulator_disable(st->reg);
372	return ret;
373}
374
375static int ad5686_remove(struct spi_device *spi)
376{
377	struct iio_dev *indio_dev = spi_get_drvdata(spi);
378	struct ad5686_state *st = iio_priv(indio_dev);
379
380	iio_device_unregister(indio_dev);
381	if (!IS_ERR(st->reg))
382		regulator_disable(st->reg);
383
384	return 0;
385}
386
387static const struct spi_device_id ad5686_id[] = {
388	{"ad5684", ID_AD5684},
389	{"ad5685", ID_AD5685},
390	{"ad5686", ID_AD5686},
391	{}
392};
393MODULE_DEVICE_TABLE(spi, ad5686_id);
394
395static struct spi_driver ad5686_driver = {
396	.driver = {
397		   .name = "ad5686",
398		   },
399	.probe = ad5686_probe,
400	.remove = ad5686_remove,
401	.id_table = ad5686_id,
402};
403module_spi_driver(ad5686_driver);
404
405MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
406MODULE_DESCRIPTION("Analog Devices AD5686/85/84 DAC");
407MODULE_LICENSE("GPL v2");
408