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] ____cacheline_aligned; 56 }; 57 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 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 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 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 }; 105 106 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 } 115 116 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 }; 165 166 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 } 190 191 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 } 223 224 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 }; 235 236 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 } 294 295 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