1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * ti-dac082s085.c - Texas Instruments 8/10/12-bit 2/4-channel DAC driver
4 *
5 * Copyright (C) 2017 KUNBUS GmbH
6 *
7 * https://www.ti.com/lit/ds/symlink/dac082s085.pdf
8 * https://www.ti.com/lit/ds/symlink/dac102s085.pdf
9 * https://www.ti.com/lit/ds/symlink/dac122s085.pdf
10 * https://www.ti.com/lit/ds/symlink/dac084s085.pdf
11 * https://www.ti.com/lit/ds/symlink/dac104s085.pdf
12 * https://www.ti.com/lit/ds/symlink/dac124s085.pdf
13 */
14
15#include <linux/iio/iio.h>
16#include <linux/module.h>
17#include <linux/mod_devicetable.h>
18#include <linux/regulator/consumer.h>
19#include <linux/spi/spi.h>
20
21enum { dual_8bit, dual_10bit, dual_12bit, quad_8bit, quad_10bit, quad_12bit };
22
23struct ti_dac_spec {
24	u8 num_channels;
25	u8 resolution;
26};
27
28static const struct ti_dac_spec ti_dac_spec[] = {
29	[dual_8bit]  = { .num_channels = 2, .resolution = 8  },
30	[dual_10bit] = { .num_channels = 2, .resolution = 10 },
31	[dual_12bit] = { .num_channels = 2, .resolution = 12 },
32	[quad_8bit]  = { .num_channels = 4, .resolution = 8  },
33	[quad_10bit] = { .num_channels = 4, .resolution = 10 },
34	[quad_12bit] = { .num_channels = 4, .resolution = 12 },
35};
36
37/**
38 * struct ti_dac_chip - TI DAC chip
39 * @lock: protects write sequences
40 * @vref: regulator generating Vref
41 * @mesg: SPI message to perform a write
42 * @xfer: SPI transfer used by @mesg
43 * @val: cached value of each output
44 * @powerdown: whether the chip is powered down
45 * @powerdown_mode: selected by the user
46 * @resolution: resolution of the chip
47 * @buf: buffer for @xfer
48 */
49struct ti_dac_chip {
50	struct mutex lock;
51	struct regulator *vref;
52	struct spi_message mesg;
53	struct spi_transfer xfer;
54	u16 val[4];
55	bool powerdown;
56	u8 powerdown_mode;
57	u8 resolution;
58	u8 buf[2] ____cacheline_aligned;
59};
60
61#define WRITE_NOT_UPDATE(chan)	(0x00 | (chan) << 6)
62#define WRITE_AND_UPDATE(chan)	(0x10 | (chan) << 6)
63#define WRITE_ALL_UPDATE	 0x20
64#define POWERDOWN(mode) 	(0x30 | ((mode) + 1) << 6)
65
66static int ti_dac_cmd(struct ti_dac_chip *ti_dac, u8 cmd, u16 val)
67{
68	u8 shift = 12 - ti_dac->resolution;
69
70	ti_dac->buf[0] = cmd | (val >> (8 - shift));
71	ti_dac->buf[1] = (val << shift) & 0xff;
72	return spi_sync(ti_dac->mesg.spi, &ti_dac->mesg);
73}
74
75static const char * const ti_dac_powerdown_modes[] = {
76	"2.5kohm_to_gnd", "100kohm_to_gnd", "three_state",
77};
78
79static int ti_dac_get_powerdown_mode(struct iio_dev *indio_dev,
80				     const struct iio_chan_spec *chan)
81{
82	struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
83
84	return ti_dac->powerdown_mode;
85}
86
87static int ti_dac_set_powerdown_mode(struct iio_dev *indio_dev,
88				     const struct iio_chan_spec *chan,
89				     unsigned int mode)
90{
91	struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
92	int ret = 0;
93
94	if (ti_dac->powerdown_mode == mode)
95		return 0;
96
97	mutex_lock(&ti_dac->lock);
98	if (ti_dac->powerdown) {
99		ret = ti_dac_cmd(ti_dac, POWERDOWN(mode), 0);
100		if (ret)
101			goto out;
102	}
103	ti_dac->powerdown_mode = mode;
104
105out:
106	mutex_unlock(&ti_dac->lock);
107	return ret;
108}
109
110static const struct iio_enum ti_dac_powerdown_mode = {
111	.items = ti_dac_powerdown_modes,
112	.num_items = ARRAY_SIZE(ti_dac_powerdown_modes),
113	.get = ti_dac_get_powerdown_mode,
114	.set = ti_dac_set_powerdown_mode,
115};
116
117static ssize_t ti_dac_read_powerdown(struct iio_dev *indio_dev,
118				     uintptr_t private,
119				     const struct iio_chan_spec *chan,
120				     char *buf)
121{
122	struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
123
124	return sprintf(buf, "%d\n", ti_dac->powerdown);
125}
126
127static ssize_t ti_dac_write_powerdown(struct iio_dev *indio_dev,
128				      uintptr_t private,
129				      const struct iio_chan_spec *chan,
130				      const char *buf, size_t len)
131{
132	struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
133	bool powerdown;
134	int ret;
135
136	ret = strtobool(buf, &powerdown);
137	if (ret)
138		return ret;
139
140	if (ti_dac->powerdown == powerdown)
141		return len;
142
143	mutex_lock(&ti_dac->lock);
144	if (powerdown)
145		ret = ti_dac_cmd(ti_dac, POWERDOWN(ti_dac->powerdown_mode), 0);
146	else
147		ret = ti_dac_cmd(ti_dac, WRITE_AND_UPDATE(0), ti_dac->val[0]);
148	if (!ret)
149		ti_dac->powerdown = powerdown;
150	mutex_unlock(&ti_dac->lock);
151
152	return ret ? ret : len;
153}
154
155static const struct iio_chan_spec_ext_info ti_dac_ext_info[] = {
156	{
157		.name	   = "powerdown",
158		.read	   = ti_dac_read_powerdown,
159		.write	   = ti_dac_write_powerdown,
160		.shared	   = IIO_SHARED_BY_TYPE,
161	},
162	IIO_ENUM("powerdown_mode", IIO_SHARED_BY_TYPE, &ti_dac_powerdown_mode),
163	IIO_ENUM_AVAILABLE("powerdown_mode", &ti_dac_powerdown_mode),
164	{ },
165};
166
167#define TI_DAC_CHANNEL(chan) {					\
168	.type = IIO_VOLTAGE,					\
169	.channel = (chan),					\
170	.address = (chan),					\
171	.indexed = true,					\
172	.output = true,						\
173	.datasheet_name = (const char[]){ 'A' + (chan), 0 },	\
174	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
175	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
176	.ext_info = ti_dac_ext_info,				\
177}
178
179static const struct iio_chan_spec ti_dac_channels[] = {
180	TI_DAC_CHANNEL(0),
181	TI_DAC_CHANNEL(1),
182	TI_DAC_CHANNEL(2),
183	TI_DAC_CHANNEL(3),
184};
185
186static int ti_dac_read_raw(struct iio_dev *indio_dev,
187			   struct iio_chan_spec const *chan,
188			   int *val, int *val2, long mask)
189{
190	struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
191	int ret;
192
193	switch (mask) {
194	case IIO_CHAN_INFO_RAW:
195		*val = ti_dac->val[chan->channel];
196		ret = IIO_VAL_INT;
197		break;
198
199	case IIO_CHAN_INFO_SCALE:
200		ret = regulator_get_voltage(ti_dac->vref);
201		if (ret < 0)
202			return ret;
203
204		*val = ret / 1000;
205		*val2 = ti_dac->resolution;
206		ret = IIO_VAL_FRACTIONAL_LOG2;
207		break;
208
209	default:
210		ret = -EINVAL;
211	}
212
213	return ret;
214}
215
216static int ti_dac_write_raw(struct iio_dev *indio_dev,
217			    struct iio_chan_spec const *chan,
218			    int val, int val2, long mask)
219{
220	struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
221	int ret;
222
223	switch (mask) {
224	case IIO_CHAN_INFO_RAW:
225		if (ti_dac->val[chan->channel] == val)
226			return 0;
227
228		if (val >= (1 << ti_dac->resolution) || val < 0)
229			return -EINVAL;
230
231		if (ti_dac->powerdown)
232			return -EBUSY;
233
234		mutex_lock(&ti_dac->lock);
235		ret = ti_dac_cmd(ti_dac, WRITE_AND_UPDATE(chan->channel), val);
236		if (!ret)
237			ti_dac->val[chan->channel] = val;
238		mutex_unlock(&ti_dac->lock);
239		break;
240
241	default:
242		ret = -EINVAL;
243	}
244
245	return ret;
246}
247
248static int ti_dac_write_raw_get_fmt(struct iio_dev *indio_dev,
249				    struct iio_chan_spec const *chan, long mask)
250{
251	return IIO_VAL_INT;
252}
253
254static const struct iio_info ti_dac_info = {
255	.read_raw	   = ti_dac_read_raw,
256	.write_raw	   = ti_dac_write_raw,
257	.write_raw_get_fmt = ti_dac_write_raw_get_fmt,
258};
259
260static int ti_dac_probe(struct spi_device *spi)
261{
262	struct device *dev = &spi->dev;
263	const struct ti_dac_spec *spec;
264	struct ti_dac_chip *ti_dac;
265	struct iio_dev *indio_dev;
266	int ret;
267
268	indio_dev = devm_iio_device_alloc(dev, sizeof(*ti_dac));
269	if (!indio_dev)
270		return -ENOMEM;
271
272	indio_dev->info = &ti_dac_info;
273	indio_dev->name = spi->modalias;
274	indio_dev->modes = INDIO_DIRECT_MODE;
275	indio_dev->channels = ti_dac_channels;
276	spi_set_drvdata(spi, indio_dev);
277
278	ti_dac = iio_priv(indio_dev);
279	ti_dac->xfer.tx_buf = &ti_dac->buf;
280	ti_dac->xfer.len = sizeof(ti_dac->buf);
281	spi_message_init_with_transfers(&ti_dac->mesg, &ti_dac->xfer, 1);
282	ti_dac->mesg.spi = spi;
283
284	spec = &ti_dac_spec[spi_get_device_id(spi)->driver_data];
285	indio_dev->num_channels = spec->num_channels;
286	ti_dac->resolution = spec->resolution;
287
288	ti_dac->vref = devm_regulator_get(dev, "vref");
289	if (IS_ERR(ti_dac->vref))
290		return PTR_ERR(ti_dac->vref);
291
292	ret = regulator_enable(ti_dac->vref);
293	if (ret < 0)
294		return ret;
295
296	mutex_init(&ti_dac->lock);
297
298	ret = ti_dac_cmd(ti_dac, WRITE_ALL_UPDATE, 0);
299	if (ret) {
300		dev_err(dev, "failed to initialize outputs to 0\n");
301		goto err;
302	}
303
304	ret = iio_device_register(indio_dev);
305	if (ret)
306		goto err;
307
308	return 0;
309
310err:
311	mutex_destroy(&ti_dac->lock);
312	regulator_disable(ti_dac->vref);
313	return ret;
314}
315
316static int ti_dac_remove(struct spi_device *spi)
317{
318	struct iio_dev *indio_dev = spi_get_drvdata(spi);
319	struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
320
321	iio_device_unregister(indio_dev);
322	mutex_destroy(&ti_dac->lock);
323	regulator_disable(ti_dac->vref);
324
325	return 0;
326}
327
328static const struct of_device_id ti_dac_of_id[] = {
329	{ .compatible = "ti,dac082s085" },
330	{ .compatible = "ti,dac102s085" },
331	{ .compatible = "ti,dac122s085" },
332	{ .compatible = "ti,dac084s085" },
333	{ .compatible = "ti,dac104s085" },
334	{ .compatible = "ti,dac124s085" },
335	{ }
336};
337MODULE_DEVICE_TABLE(of, ti_dac_of_id);
338
339static const struct spi_device_id ti_dac_spi_id[] = {
340	{ "dac082s085", dual_8bit  },
341	{ "dac102s085", dual_10bit },
342	{ "dac122s085", dual_12bit },
343	{ "dac084s085", quad_8bit  },
344	{ "dac104s085", quad_10bit },
345	{ "dac124s085", quad_12bit },
346	{ }
347};
348MODULE_DEVICE_TABLE(spi, ti_dac_spi_id);
349
350static struct spi_driver ti_dac_driver = {
351	.driver = {
352		.name		= "ti-dac082s085",
353		.of_match_table	= ti_dac_of_id,
354	},
355	.probe	  = ti_dac_probe,
356	.remove   = ti_dac_remove,
357	.id_table = ti_dac_spi_id,
358};
359module_spi_driver(ti_dac_driver);
360
361MODULE_AUTHOR("Lukas Wunner <lukas@wunner.de>");
362MODULE_DESCRIPTION("Texas Instruments 8/10/12-bit 2/4-channel DAC driver");
363MODULE_LICENSE("GPL v2");
364