1/*
2 * AD5504, AD5501 High Voltage Digital to Analog Converter
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/kernel.h>
13#include <linux/spi/spi.h>
14#include <linux/slab.h>
15#include <linux/sysfs.h>
16#include <linux/regulator/consumer.h>
17#include <linux/module.h>
18#include <linux/bitops.h>
19
20#include <linux/iio/iio.h>
21#include <linux/iio/sysfs.h>
22#include <linux/iio/events.h>
23#include <linux/iio/dac/ad5504.h>
24
25#define AD5504_RES_MASK			GENMASK(11, 0)
26#define AD5504_CMD_READ			BIT(15)
27#define AD5504_CMD_WRITE		0
28#define AD5504_ADDR(addr)		((addr) << 12)
29
30/* Registers */
31#define AD5504_ADDR_NOOP		0
32#define AD5504_ADDR_DAC(x)		((x) + 1)
33#define AD5504_ADDR_ALL_DAC		5
34#define AD5504_ADDR_CTRL		7
35
36/* Control Register */
37#define AD5504_DAC_PWR(ch)		((ch) << 2)
38#define AD5504_DAC_PWRDWN_MODE(mode)	((mode) << 6)
39#define AD5504_DAC_PWRDN_20K		0
40#define AD5504_DAC_PWRDN_3STATE		1
41
42/**
43 * struct ad5446_state - driver instance specific data
44 * @spi:			spi_device
45 * @reg:		supply regulator
46 * @vref_mv:		actual reference voltage used
47 * @pwr_down_mask	power down mask
48 * @pwr_down_mode	current power down mode
49 * @data:		transfer buffer
50 */
51struct ad5504_state {
52	struct spi_device		*spi;
53	struct regulator		*reg;
54	unsigned short			vref_mv;
55	unsigned			pwr_down_mask;
56	unsigned			pwr_down_mode;
57
58	__be16				data[2] ____cacheline_aligned;
59};
60
61/**
62 * ad5504_supported_device_ids:
63 */
64
65enum ad5504_supported_device_ids {
66	ID_AD5504,
67	ID_AD5501,
68};
69
70static int ad5504_spi_write(struct ad5504_state *st, u8 addr, u16 val)
71{
72	st->data[0] = cpu_to_be16(AD5504_CMD_WRITE | AD5504_ADDR(addr) |
73			      (val & AD5504_RES_MASK));
74
75	return spi_write(st->spi, &st->data[0], 2);
76}
77
78static int ad5504_spi_read(struct ad5504_state *st, u8 addr)
79{
80	int ret;
81	struct spi_transfer t = {
82	    .tx_buf = &st->data[0],
83	    .rx_buf = &st->data[1],
84	    .len = 2,
85	};
86
87	st->data[0] = cpu_to_be16(AD5504_CMD_READ | AD5504_ADDR(addr));
88	ret = spi_sync_transfer(st->spi, &t, 1);
89	if (ret < 0)
90		return ret;
91
92	return be16_to_cpu(st->data[1]) & AD5504_RES_MASK;
93}
94
95static int ad5504_read_raw(struct iio_dev *indio_dev,
96			   struct iio_chan_spec const *chan,
97			   int *val,
98			   int *val2,
99			   long m)
100{
101	struct ad5504_state *st = iio_priv(indio_dev);
102	int ret;
103
104	switch (m) {
105	case IIO_CHAN_INFO_RAW:
106		ret = ad5504_spi_read(st, chan->address);
107		if (ret < 0)
108			return ret;
109
110		*val = ret;
111
112		return IIO_VAL_INT;
113	case IIO_CHAN_INFO_SCALE:
114		*val = st->vref_mv;
115		*val2 = chan->scan_type.realbits;
116		return IIO_VAL_FRACTIONAL_LOG2;
117	}
118	return -EINVAL;
119}
120
121static int ad5504_write_raw(struct iio_dev *indio_dev,
122			       struct iio_chan_spec const *chan,
123			       int val,
124			       int val2,
125			       long mask)
126{
127	struct ad5504_state *st = iio_priv(indio_dev);
128
129	switch (mask) {
130	case IIO_CHAN_INFO_RAW:
131		if (val >= (1 << chan->scan_type.realbits) || val < 0)
132			return -EINVAL;
133
134		return ad5504_spi_write(st, chan->address, val);
135	default:
136		return -EINVAL;
137	}
138}
139
140static const char * const ad5504_powerdown_modes[] = {
141	"20kohm_to_gnd",
142	"three_state",
143};
144
145static int ad5504_get_powerdown_mode(struct iio_dev *indio_dev,
146	const struct iio_chan_spec *chan)
147{
148	struct ad5504_state *st = iio_priv(indio_dev);
149
150	return st->pwr_down_mode;
151}
152
153static int ad5504_set_powerdown_mode(struct iio_dev *indio_dev,
154	const struct iio_chan_spec *chan, unsigned int mode)
155{
156	struct ad5504_state *st = iio_priv(indio_dev);
157
158	st->pwr_down_mode = mode;
159
160	return 0;
161}
162
163static const struct iio_enum ad5504_powerdown_mode_enum = {
164	.items = ad5504_powerdown_modes,
165	.num_items = ARRAY_SIZE(ad5504_powerdown_modes),
166	.get = ad5504_get_powerdown_mode,
167	.set = ad5504_set_powerdown_mode,
168};
169
170static ssize_t ad5504_read_dac_powerdown(struct iio_dev *indio_dev,
171	uintptr_t private, const struct iio_chan_spec *chan, char *buf)
172{
173	struct ad5504_state *st = iio_priv(indio_dev);
174
175	return sprintf(buf, "%d\n",
176			!(st->pwr_down_mask & (1 << chan->channel)));
177}
178
179static ssize_t ad5504_write_dac_powerdown(struct iio_dev *indio_dev,
180	uintptr_t private, const struct iio_chan_spec *chan, const char *buf,
181	size_t len)
182{
183	bool pwr_down;
184	int ret;
185	struct ad5504_state *st = iio_priv(indio_dev);
186
187	ret = strtobool(buf, &pwr_down);
188	if (ret)
189		return ret;
190
191	if (pwr_down)
192		st->pwr_down_mask |= (1 << chan->channel);
193	else
194		st->pwr_down_mask &= ~(1 << chan->channel);
195
196	ret = ad5504_spi_write(st, AD5504_ADDR_CTRL,
197				AD5504_DAC_PWRDWN_MODE(st->pwr_down_mode) |
198				AD5504_DAC_PWR(st->pwr_down_mask));
199
200	/* writes to the CTRL register must be followed by a NOOP */
201	ad5504_spi_write(st, AD5504_ADDR_NOOP, 0);
202
203	return ret ? ret : len;
204}
205
206static IIO_CONST_ATTR(temp0_thresh_rising_value, "110000");
207static IIO_CONST_ATTR(temp0_thresh_rising_en, "1");
208
209static struct attribute *ad5504_ev_attributes[] = {
210	&iio_const_attr_temp0_thresh_rising_value.dev_attr.attr,
211	&iio_const_attr_temp0_thresh_rising_en.dev_attr.attr,
212	NULL,
213};
214
215static struct attribute_group ad5504_ev_attribute_group = {
216	.attrs = ad5504_ev_attributes,
217	.name = "events",
218};
219
220static irqreturn_t ad5504_event_handler(int irq, void *private)
221{
222	iio_push_event(private,
223		       IIO_UNMOD_EVENT_CODE(IIO_TEMP,
224					    0,
225					    IIO_EV_TYPE_THRESH,
226					    IIO_EV_DIR_RISING),
227		       iio_get_time_ns());
228
229	return IRQ_HANDLED;
230}
231
232static const struct iio_info ad5504_info = {
233	.write_raw = ad5504_write_raw,
234	.read_raw = ad5504_read_raw,
235	.event_attrs = &ad5504_ev_attribute_group,
236	.driver_module = THIS_MODULE,
237};
238
239static const struct iio_chan_spec_ext_info ad5504_ext_info[] = {
240	{
241		.name = "powerdown",
242		.read = ad5504_read_dac_powerdown,
243		.write = ad5504_write_dac_powerdown,
244		.shared = IIO_SEPARATE,
245	},
246	IIO_ENUM("powerdown_mode", IIO_SHARED_BY_TYPE,
247		 &ad5504_powerdown_mode_enum),
248	IIO_ENUM_AVAILABLE("powerdown_mode", &ad5504_powerdown_mode_enum),
249	{ },
250};
251
252#define AD5504_CHANNEL(_chan) { \
253	.type = IIO_VOLTAGE, \
254	.indexed = 1, \
255	.output = 1, \
256	.channel = (_chan), \
257	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
258	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
259	.address = AD5504_ADDR_DAC(_chan), \
260	.scan_type = { \
261		.sign = 'u', \
262		.realbits = 12, \
263		.storagebits = 16, \
264	}, \
265	.ext_info = ad5504_ext_info, \
266}
267
268static const struct iio_chan_spec ad5504_channels[] = {
269	AD5504_CHANNEL(0),
270	AD5504_CHANNEL(1),
271	AD5504_CHANNEL(2),
272	AD5504_CHANNEL(3),
273};
274
275static int ad5504_probe(struct spi_device *spi)
276{
277	struct ad5504_platform_data *pdata = spi->dev.platform_data;
278	struct iio_dev *indio_dev;
279	struct ad5504_state *st;
280	struct regulator *reg;
281	int ret, voltage_uv = 0;
282
283	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
284	if (!indio_dev)
285		return -ENOMEM;
286	reg = devm_regulator_get(&spi->dev, "vcc");
287	if (!IS_ERR(reg)) {
288		ret = regulator_enable(reg);
289		if (ret)
290			return ret;
291
292		ret = regulator_get_voltage(reg);
293		if (ret < 0)
294			goto error_disable_reg;
295
296		voltage_uv = ret;
297	}
298
299	spi_set_drvdata(spi, indio_dev);
300	st = iio_priv(indio_dev);
301	if (voltage_uv)
302		st->vref_mv = voltage_uv / 1000;
303	else if (pdata)
304		st->vref_mv = pdata->vref_mv;
305	else
306		dev_warn(&spi->dev, "reference voltage unspecified\n");
307
308	st->reg = reg;
309	st->spi = spi;
310	indio_dev->dev.parent = &spi->dev;
311	indio_dev->name = spi_get_device_id(st->spi)->name;
312	indio_dev->info = &ad5504_info;
313	if (spi_get_device_id(st->spi)->driver_data == ID_AD5501)
314		indio_dev->num_channels = 1;
315	else
316		indio_dev->num_channels = 4;
317	indio_dev->channels = ad5504_channels;
318	indio_dev->modes = INDIO_DIRECT_MODE;
319
320	if (spi->irq) {
321		ret = devm_request_threaded_irq(&spi->dev, spi->irq,
322					   NULL,
323					   &ad5504_event_handler,
324					   IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
325					   spi_get_device_id(st->spi)->name,
326					   indio_dev);
327		if (ret)
328			goto error_disable_reg;
329	}
330
331	ret = iio_device_register(indio_dev);
332	if (ret)
333		goto error_disable_reg;
334
335	return 0;
336
337error_disable_reg:
338	if (!IS_ERR(reg))
339		regulator_disable(reg);
340
341	return ret;
342}
343
344static int ad5504_remove(struct spi_device *spi)
345{
346	struct iio_dev *indio_dev = spi_get_drvdata(spi);
347	struct ad5504_state *st = iio_priv(indio_dev);
348
349	iio_device_unregister(indio_dev);
350
351	if (!IS_ERR(st->reg))
352		regulator_disable(st->reg);
353
354	return 0;
355}
356
357static const struct spi_device_id ad5504_id[] = {
358	{"ad5504", ID_AD5504},
359	{"ad5501", ID_AD5501},
360	{}
361};
362MODULE_DEVICE_TABLE(spi, ad5504_id);
363
364static struct spi_driver ad5504_driver = {
365	.driver = {
366		   .name = "ad5504",
367		   .owner = THIS_MODULE,
368		   },
369	.probe = ad5504_probe,
370	.remove = ad5504_remove,
371	.id_table = ad5504_id,
372};
373module_spi_driver(ad5504_driver);
374
375MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
376MODULE_DESCRIPTION("Analog Devices AD5501/AD5501 DAC");
377MODULE_LICENSE("GPL v2");
378