xref: /openbmc/linux/drivers/iio/dac/ti-dac7311.c (revision 3637c49e)
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 
14 enum {
15 	ID_DAC5311 = 0,
16 	ID_DAC6311,
17 	ID_DAC7311,
18 };
19 
20 enum {
21 	POWER_1KOHM_TO_GND = 0,
22 	POWER_100KOHM_TO_GND,
23 	POWER_TRI_STATE,
24 };
25 
26 struct ti_dac_spec {
27 	u8 resolution;
28 };
29 
30 static 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  */
47 struct 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 
ti_dac_get_power(struct ti_dac_chip * ti_dac,bool powerdown)58 static 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 
ti_dac_cmd(struct ti_dac_chip * ti_dac,u8 power,u16 val)66 static 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 
75 static const char * const ti_dac_powerdown_modes[] = {
76 	"1kohm_to_gnd",
77 	"100kohm_to_gnd",
78 	"three_state",
79 };
80 
ti_dac_get_powerdown_mode(struct iio_dev * indio_dev,const struct iio_chan_spec * chan)81 static 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 
ti_dac_set_powerdown_mode(struct iio_dev * indio_dev,const struct iio_chan_spec * chan,unsigned int mode)89 static 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 
99 static 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 
ti_dac_read_powerdown(struct iio_dev * indio_dev,uintptr_t private,const struct iio_chan_spec * chan,char * buf)106 static 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 
ti_dac_write_powerdown(struct iio_dev * indio_dev,uintptr_t private,const struct iio_chan_spec * chan,const char * buf,size_t len)116 static 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 
141 static 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 
162 static const struct iio_chan_spec ti_dac_channels[] = {
163 	TI_DAC_CHANNEL(0),
164 };
165 
ti_dac_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)166 static 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 
ti_dac_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)191 static 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 
ti_dac_write_raw_get_fmt(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,long mask)224 static 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 
230 static 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 
ti_dac_probe(struct spi_device * spi)236 static 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 		dev_err(dev, "can not allocate iio device\n");
247 		return -ENOMEM;
248 	}
249 
250 	spi->mode = SPI_MODE_1;
251 	spi->bits_per_word = 16;
252 	spi_setup(spi);
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 
289 err:
290 	mutex_destroy(&ti_dac->lock);
291 	regulator_disable(ti_dac->vref);
292 	return ret;
293 }
294 
ti_dac_remove(struct spi_device * spi)295 static 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 
305 static const struct of_device_id ti_dac_of_id[] = {
306 	{ .compatible = "ti,dac5311" },
307 	{ .compatible = "ti,dac6311" },
308 	{ .compatible = "ti,dac7311" },
309 	{ }
310 };
311 MODULE_DEVICE_TABLE(of, ti_dac_of_id);
312 
313 static const struct spi_device_id ti_dac_spi_id[] = {
314 	{ "dac5311", ID_DAC5311  },
315 	{ "dac6311", ID_DAC6311 },
316 	{ "dac7311", ID_DAC7311 },
317 	{ }
318 };
319 MODULE_DEVICE_TABLE(spi, ti_dac_spi_id);
320 
321 static 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 };
330 module_spi_driver(ti_dac_driver);
331 
332 MODULE_AUTHOR("Charles-Antoine Couret <charles-antoine.couret@essensium.com>");
333 MODULE_DESCRIPTION("Texas Instruments 8/10/12-bit 1-channel DAC driver");
334 MODULE_LICENSE("GPL v2");
335