ti-dac7311.c

  1// SPDX-License-Identifier: GPL-2.0
  2/* ti-dac7311.c - Texas Instruments 8/10/12-bit 1-channel DAC driver
  3 *
  4 * Copyright (C) 2018 CMC NV
  5 *
  6 * https://www.ti.com/lit/ds/symlink/dac7311.pdf
  7 */
  8
  9#include <linux/iio/iio.h>
 10#include <linux/module.h>
 11#include <linux/regulator/consumer.h>
 12#include <linux/spi/spi.h>
 13
 14enum {
 15	ID_DAC5311 = 0,
 16	ID_DAC6311,
 17	ID_DAC7311,
 18};
 19
 20enum {
 21	POWER_1KOHM_TO_GND = 0,
 22	POWER_100KOHM_TO_GND,
 23	POWER_TRI_STATE,
 24};
 25
 26struct ti_dac_spec {
 27	u8 resolution;
 28};
 29
 30static const struct ti_dac_spec ti_dac_spec[] = {
 31	[ID_DAC5311] = { .resolution = 8 },
 32	[ID_DAC6311] = { .resolution = 10 },
 33	[ID_DAC7311] = { .resolution = 12 },
 34};
 35
 36/**
 37 * struct ti_dac_chip - TI DAC chip
 38 * @lock: protects write sequences
 39 * @vref: regulator generating Vref
 40 * @spi: SPI device to send data to the device
 41 * @val: cached value
 42 * @powerdown: whether the chip is powered down
 43 * @powerdown_mode: selected by the user
 44 * @resolution: resolution of the chip
 45 * @buf: buffer for transfer data
 46 */
 47struct ti_dac_chip {
 48	struct mutex lock;
 49	struct regulator *vref;
 50	struct spi_device *spi;
 51	u16 val;
 52	bool powerdown;
 53	u8 powerdown_mode;
 54	u8 resolution;
 55	u8 buf[2] __aligned(IIO_DMA_MINALIGN);
 56};
 57
 58static u8 ti_dac_get_power(struct ti_dac_chip *ti_dac, bool powerdown)
 59{
 60	if (powerdown)
 61		return ti_dac->powerdown_mode + 1;
 62
 63	return 0;
 64}
 65
 66static int ti_dac_cmd(struct ti_dac_chip *ti_dac, u8 power, u16 val)
 67{
 68	u8 shift = 14 - ti_dac->resolution;
 69
 70	ti_dac->buf[0] = (val << shift) & 0xFF;
 71	ti_dac->buf[1] = (power << 6) | (val >> (8 - shift));
 72	return spi_write(ti_dac->spi, ti_dac->buf, 2);
 73}
 74
 75static const char * const ti_dac_powerdown_modes[] = {
 76	"1kohm_to_gnd",
 77	"100kohm_to_gnd",
 78	"three_state",
 79};
 80
 81static int ti_dac_get_powerdown_mode(struct iio_dev *indio_dev,
 82				     const struct iio_chan_spec *chan)
 83{
 84	struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
 85
 86	return ti_dac->powerdown_mode;
 87}
 88
 89static int ti_dac_set_powerdown_mode(struct iio_dev *indio_dev,
 90				     const struct iio_chan_spec *chan,
 91				     unsigned int mode)
 92{
 93	struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
 94
 95	ti_dac->powerdown_mode = mode;
 96	return 0;
 97}
 98
 99static const struct iio_enum ti_dac_powerdown_mode = {
100	.items = ti_dac_powerdown_modes,
101	.num_items = ARRAY_SIZE(ti_dac_powerdown_modes),
102	.get = ti_dac_get_powerdown_mode,
103	.set = ti_dac_set_powerdown_mode,
104};
105
106static ssize_t ti_dac_read_powerdown(struct iio_dev *indio_dev,
107				     uintptr_t private,
108				     const struct iio_chan_spec *chan,
109				     char *buf)
110{
111	struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
112
113	return sysfs_emit(buf, "%d\n", ti_dac->powerdown);
114}
115
116static ssize_t ti_dac_write_powerdown(struct iio_dev *indio_dev,
117				      uintptr_t private,
118				      const struct iio_chan_spec *chan,
119				      const char *buf, size_t len)
120{
121	struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
122	bool powerdown;
123	u8 power;
124	int ret;
125
126	ret = kstrtobool(buf, &powerdown);
127	if (ret)
128		return ret;
129
130	power = ti_dac_get_power(ti_dac, powerdown);
131
132	mutex_lock(&ti_dac->lock);
133	ret = ti_dac_cmd(ti_dac, power, 0);
134	if (!ret)
135		ti_dac->powerdown = powerdown;
136	mutex_unlock(&ti_dac->lock);
137
138	return ret ? ret : len;
139}
140
141static const struct iio_chan_spec_ext_info ti_dac_ext_info[] = {
142	{
143		.name	   = "powerdown",
144		.read	   = ti_dac_read_powerdown,
145		.write	   = ti_dac_write_powerdown,
146		.shared	   = IIO_SHARED_BY_TYPE,
147	},
148	IIO_ENUM("powerdown_mode", IIO_SHARED_BY_TYPE, &ti_dac_powerdown_mode),
149	IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE, &ti_dac_powerdown_mode),
150	{ }
151};
152
153#define TI_DAC_CHANNEL(chan) {					\
154	.type = IIO_VOLTAGE,					\
155	.channel = (chan),					\
156	.output = true,						\
157	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
158	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
159	.ext_info = ti_dac_ext_info,				\
160}
161
162static const struct iio_chan_spec ti_dac_channels[] = {
163	TI_DAC_CHANNEL(0),
164};
165
166static int ti_dac_read_raw(struct iio_dev *indio_dev,
167			   struct iio_chan_spec const *chan,
168			   int *val, int *val2, long mask)
169{
170	struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
171	int ret;
172
173	switch (mask) {
174	case IIO_CHAN_INFO_RAW:
175		*val = ti_dac->val;
176		return IIO_VAL_INT;
177
178	case IIO_CHAN_INFO_SCALE:
179		ret = regulator_get_voltage(ti_dac->vref);
180		if (ret < 0)
181			return ret;
182
183		*val = ret / 1000;
184		*val2 = ti_dac->resolution;
185		return IIO_VAL_FRACTIONAL_LOG2;
186	}
187
188	return -EINVAL;
189}
190
191static int ti_dac_write_raw(struct iio_dev *indio_dev,
192			    struct iio_chan_spec const *chan,
193			    int val, int val2, long mask)
194{
195	struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
196	u8 power = ti_dac_get_power(ti_dac, ti_dac->powerdown);
197	int ret;
198
199	switch (mask) {
200	case IIO_CHAN_INFO_RAW:
201		if (ti_dac->val == val)
202			return 0;
203
204		if (val >= (1 << ti_dac->resolution) || val < 0)
205			return -EINVAL;
206
207		if (ti_dac->powerdown)
208			return -EBUSY;
209
210		mutex_lock(&ti_dac->lock);
211		ret = ti_dac_cmd(ti_dac, power, val);
212		if (!ret)
213			ti_dac->val = val;
214		mutex_unlock(&ti_dac->lock);
215		break;
216
217	default:
218		ret = -EINVAL;
219	}
220
221	return ret;
222}
223
224static int ti_dac_write_raw_get_fmt(struct iio_dev *indio_dev,
225				    struct iio_chan_spec const *chan, long mask)
226{
227	return IIO_VAL_INT;
228}
229
230static const struct iio_info ti_dac_info = {
231	.read_raw	   = ti_dac_read_raw,
232	.write_raw	   = ti_dac_write_raw,
233	.write_raw_get_fmt = ti_dac_write_raw_get_fmt,
234};
235
236static int ti_dac_probe(struct spi_device *spi)
237{
238	struct device *dev = &spi->dev;
239	const struct ti_dac_spec *spec;
240	struct ti_dac_chip *ti_dac;
241	struct iio_dev *indio_dev;
242	int ret;
243
244	indio_dev = devm_iio_device_alloc(dev, sizeof(*ti_dac));
245	if (!indio_dev)
246		return -ENOMEM;
247
248	spi->mode = SPI_MODE_1;
249	spi->bits_per_word = 16;
250	ret = spi_setup(spi);
251	if (ret < 0)
252		return dev_err_probe(dev, ret, "spi_setup failed\n");
253
254	indio_dev->info = &ti_dac_info;
255	indio_dev->name = spi_get_device_id(spi)->name;
256	indio_dev->modes = INDIO_DIRECT_MODE;
257	indio_dev->channels = ti_dac_channels;
258	spi_set_drvdata(spi, indio_dev);
259
260	ti_dac = iio_priv(indio_dev);
261	ti_dac->powerdown = false;
262	ti_dac->spi = spi;
263
264	spec = &ti_dac_spec[spi_get_device_id(spi)->driver_data];
265	indio_dev->num_channels = 1;
266	ti_dac->resolution = spec->resolution;
267
268	ti_dac->vref = devm_regulator_get(dev, "vref");
269	if (IS_ERR(ti_dac->vref))
270		return dev_err_probe(dev, PTR_ERR(ti_dac->vref),
271				     "error to get regulator\n");
272
273	ret = regulator_enable(ti_dac->vref);
274	if (ret < 0) {
275		dev_err(dev, "can not enable regulator\n");
276		return ret;
277	}
278
279	mutex_init(&ti_dac->lock);
280
281	ret = iio_device_register(indio_dev);
282	if (ret) {
283		dev_err(dev, "fail to register iio device: %d\n", ret);
284		goto err;
285	}
286
287	return 0;
288
289err:
290	mutex_destroy(&ti_dac->lock);
291	regulator_disable(ti_dac->vref);
292	return ret;
293}
294
295static void ti_dac_remove(struct spi_device *spi)
296{
297	struct iio_dev *indio_dev = spi_get_drvdata(spi);
298	struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
299
300	iio_device_unregister(indio_dev);
301	mutex_destroy(&ti_dac->lock);
302	regulator_disable(ti_dac->vref);
303}
304
305static const struct of_device_id ti_dac_of_id[] = {
306	{ .compatible = "ti,dac5311" },
307	{ .compatible = "ti,dac6311" },
308	{ .compatible = "ti,dac7311" },
309	{ }
310};
311MODULE_DEVICE_TABLE(of, ti_dac_of_id);
312
313static const struct spi_device_id ti_dac_spi_id[] = {
314	{ "dac5311", ID_DAC5311  },
315	{ "dac6311", ID_DAC6311 },
316	{ "dac7311", ID_DAC7311 },
317	{ }
318};
319MODULE_DEVICE_TABLE(spi, ti_dac_spi_id);
320
321static struct spi_driver ti_dac_driver = {
322	.driver = {
323		.name		= "ti-dac7311",
324		.of_match_table	= ti_dac_of_id,
325	},
326	.probe	  = ti_dac_probe,
327	.remove   = ti_dac_remove,
328	.id_table = ti_dac_spi_id,
329};
330module_spi_driver(ti_dac_driver);
331
332MODULE_AUTHOR("Charles-Antoine Couret <charles-antoine.couret@essensium.com>");
333MODULE_DESCRIPTION("Texas Instruments 8/10/12-bit 1-channel DAC driver");
334MODULE_LICENSE("GPL v2");