2 * LTC2632 Digital to analog convertors spi driver
4 * Copyright 2017 Maxime Roussin-BĂ©langer
6 * Licensed under the GPL-2.
9 #include <linux/device.h>
10 #include <linux/spi/spi.h>
11 #include <linux/module.h>
12 #include <linux/iio/iio.h>
14 #define LTC2632_DAC_CHANNELS 2
16 #define LTC2632_ADDR_DAC0 0x0
17 #define LTC2632_ADDR_DAC1 0x1
19 #define LTC2632_CMD_WRITE_INPUT_N 0x0
20 #define LTC2632_CMD_UPDATE_DAC_N 0x1
21 #define LTC2632_CMD_WRITE_INPUT_N_UPDATE_ALL 0x2
22 #define LTC2632_CMD_WRITE_INPUT_N_UPDATE_N 0x3
23 #define LTC2632_CMD_POWERDOWN_DAC_N 0x4
24 #define LTC2632_CMD_POWERDOWN_CHIP 0x5
25 #define LTC2632_CMD_INTERNAL_REFER 0x6
26 #define LTC2632_CMD_EXTERNAL_REFER 0x7
29 * struct ltc2632_chip_info - chip specific information
30 * @channels: channel spec for the DAC
31 * @vref_mv: reference voltage
33 struct ltc2632_chip_info {
34 const struct iio_chan_spec *channels;
39 * struct ltc2632_state - driver instance specific data
40 * @spi_dev: pointer to the spi_device struct
41 * @powerdown_cache_mask used to show current channel powerdown state
43 struct ltc2632_state {
44 struct spi_device *spi_dev;
45 unsigned int powerdown_cache_mask;
48 enum ltc2632_supported_device_ids {
57 static int ltc2632_spi_write(struct spi_device *spi,
58 u8 cmd, u8 addr, u16 val, u8 shift)
64 * The input shift register is 24 bits wide.
65 * The next four are the command bits, C3 to C0,
66 * followed by the 4-bit DAC address, A3 to A0, and then the
67 * 12-, 10-, 8-bit data-word. The data-word comprises the 12-,
68 * 10-, 8-bit input code followed by 4, 6, or 8 don't care bits.
70 data = (cmd << 20) | (addr << 16) | (val << shift);
75 return spi_write(spi, msg, sizeof(msg));
78 static int ltc2632_read_raw(struct iio_dev *indio_dev,
79 struct iio_chan_spec const *chan,
84 struct ltc2632_chip_info *chip_info;
86 const struct ltc2632_state *st = iio_priv(indio_dev);
87 const struct spi_device_id *spi_dev_id = spi_get_device_id(st->spi_dev);
89 chip_info = (struct ltc2632_chip_info *)spi_dev_id->driver_data;
92 case IIO_CHAN_INFO_SCALE:
93 *val = chip_info->vref_mv;
94 *val2 = chan->scan_type.realbits;
95 return IIO_VAL_FRACTIONAL_LOG2;
100 static int ltc2632_write_raw(struct iio_dev *indio_dev,
101 struct iio_chan_spec const *chan,
106 struct ltc2632_state *st = iio_priv(indio_dev);
109 case IIO_CHAN_INFO_RAW:
110 if (val >= (1 << chan->scan_type.realbits) || val < 0)
113 return ltc2632_spi_write(st->spi_dev,
114 LTC2632_CMD_WRITE_INPUT_N_UPDATE_N,
116 chan->scan_type.shift);
122 static ssize_t ltc2632_read_dac_powerdown(struct iio_dev *indio_dev,
124 const struct iio_chan_spec *chan,
127 struct ltc2632_state *st = iio_priv(indio_dev);
129 return sprintf(buf, "%d\n",
130 !!(st->powerdown_cache_mask & (1 << chan->channel)));
133 static ssize_t ltc2632_write_dac_powerdown(struct iio_dev *indio_dev,
135 const struct iio_chan_spec *chan,
141 struct ltc2632_state *st = iio_priv(indio_dev);
143 ret = strtobool(buf, &pwr_down);
148 st->powerdown_cache_mask |= (1 << chan->channel);
150 st->powerdown_cache_mask &= ~(1 << chan->channel);
152 ret = ltc2632_spi_write(st->spi_dev,
153 LTC2632_CMD_POWERDOWN_DAC_N,
154 chan->channel, 0, 0);
156 return ret ? ret : len;
159 static const struct iio_info ltc2632_info = {
160 .write_raw = ltc2632_write_raw,
161 .read_raw = ltc2632_read_raw,
162 .driver_module = THIS_MODULE,
165 static const struct iio_chan_spec_ext_info ltc2632_ext_info[] = {
168 .read = ltc2632_read_dac_powerdown,
169 .write = ltc2632_write_dac_powerdown,
170 .shared = IIO_SEPARATE,
175 #define LTC2632_CHANNEL(_chan, _bits) { \
176 .type = IIO_VOLTAGE, \
179 .channel = (_chan), \
180 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
181 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
182 .address = (_chan), \
184 .realbits = (_bits), \
185 .shift = 16 - (_bits), \
187 .ext_info = ltc2632_ext_info, \
190 #define DECLARE_LTC2632_CHANNELS(_name, _bits) \
191 const struct iio_chan_spec _name ## _channels[] = { \
192 LTC2632_CHANNEL(0, _bits), \
193 LTC2632_CHANNEL(1, _bits), \
196 static DECLARE_LTC2632_CHANNELS(ltc2632l12, 12);
197 static DECLARE_LTC2632_CHANNELS(ltc2632l10, 10);
198 static DECLARE_LTC2632_CHANNELS(ltc2632l8, 8);
200 static DECLARE_LTC2632_CHANNELS(ltc2632h12, 12);
201 static DECLARE_LTC2632_CHANNELS(ltc2632h10, 10);
202 static DECLARE_LTC2632_CHANNELS(ltc2632h8, 8);
204 static const struct ltc2632_chip_info ltc2632_chip_info_tbl[] = {
206 .channels = ltc2632l12_channels,
210 .channels = ltc2632l10_channels,
214 .channels = ltc2632l8_channels,
218 .channels = ltc2632h12_channels,
222 .channels = ltc2632h10_channels,
226 .channels = ltc2632h8_channels,
231 static int ltc2632_probe(struct spi_device *spi)
233 struct ltc2632_state *st;
234 struct iio_dev *indio_dev;
235 struct ltc2632_chip_info *chip_info;
238 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
242 st = iio_priv(indio_dev);
244 spi_set_drvdata(spi, indio_dev);
247 chip_info = (struct ltc2632_chip_info *)
248 spi_get_device_id(spi)->driver_data;
250 indio_dev->dev.parent = &spi->dev;
251 indio_dev->name = dev_of_node(&spi->dev) ? dev_of_node(&spi->dev)->name
252 : spi_get_device_id(spi)->name;
253 indio_dev->info = <c2632_info;
254 indio_dev->modes = INDIO_DIRECT_MODE;
255 indio_dev->channels = chip_info->channels;
256 indio_dev->num_channels = LTC2632_DAC_CHANNELS;
258 ret = ltc2632_spi_write(spi, LTC2632_CMD_INTERNAL_REFER, 0, 0, 0);
261 "Set internal reference command failed, %d\n", ret);
265 return devm_iio_device_register(&spi->dev, indio_dev);
268 static const struct spi_device_id ltc2632_id[] = {
269 { "ltc2632-l12", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2632L12] },
270 { "ltc2632-l10", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2632L10] },
271 { "ltc2632-l8", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2632L8] },
272 { "ltc2632-h12", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2632H12] },
273 { "ltc2632-h10", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2632H10] },
274 { "ltc2632-h8", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2632H8] },
277 MODULE_DEVICE_TABLE(spi, ltc2632_id);
279 static struct spi_driver ltc2632_driver = {
283 .probe = ltc2632_probe,
284 .id_table = ltc2632_id,
286 module_spi_driver(ltc2632_driver);
288 static const struct of_device_id ltc2632_of_match[] = {
290 .compatible = "lltc,ltc2632-l12",
291 .data = <c2632_chip_info_tbl[ID_LTC2632L12]
293 .compatible = "lltc,ltc2632-l10",
294 .data = <c2632_chip_info_tbl[ID_LTC2632L10]
296 .compatible = "lltc,ltc2632-l8",
297 .data = <c2632_chip_info_tbl[ID_LTC2632L8]
299 .compatible = "lltc,ltc2632-h12",
300 .data = <c2632_chip_info_tbl[ID_LTC2632H12]
302 .compatible = "lltc,ltc2632-h10",
303 .data = <c2632_chip_info_tbl[ID_LTC2632H10]
305 .compatible = "lltc,ltc2632-h8",
306 .data = <c2632_chip_info_tbl[ID_LTC2632H8]
310 MODULE_DEVICE_TABLE(of, ltc2632_of_match);
312 MODULE_AUTHOR("Maxime Roussin-Belanger <maxime.roussinbelanger@gmail.com>");
313 MODULE_DESCRIPTION("LTC2632 DAC SPI driver");
314 MODULE_LICENSE("GPL v2");