1 /* 2 * AD7466/7/8 AD7476/5/7/8 (A) SPI ADC driver 3 * 4 * Copyright 2010 Analog Devices Inc. 5 * 6 * Licensed under the GPL-2 or later. 7 */ 8 9 #include <linux/device.h> 10 #include <linux/kernel.h> 11 #include <linux/slab.h> 12 #include <linux/sysfs.h> 13 #include <linux/spi/spi.h> 14 #include <linux/regulator/consumer.h> 15 #include <linux/err.h> 16 #include <linux/module.h> 17 18 #include <linux/iio/iio.h> 19 #include <linux/iio/sysfs.h> 20 #include <linux/iio/buffer.h> 21 #include <linux/iio/trigger_consumer.h> 22 #include <linux/iio/triggered_buffer.h> 23 24 #define RES_MASK(bits) ((1 << (bits)) - 1) 25 26 struct ad7476_state; 27 28 struct ad7476_chip_info { 29 unsigned int int_vref_uv; 30 struct iio_chan_spec channel[2]; 31 void (*reset)(struct ad7476_state *); 32 }; 33 34 struct ad7476_state { 35 struct spi_device *spi; 36 const struct ad7476_chip_info *chip_info; 37 struct regulator *reg; 38 struct spi_transfer xfer; 39 struct spi_message msg; 40 /* 41 * DMA (thus cache coherency maintenance) requires the 42 * transfer buffers to live in their own cache lines. 43 * Make the buffer large enough for one 16 bit sample and one 64 bit 44 * aligned 64 bit timestamp. 45 */ 46 unsigned char data[ALIGN(2, sizeof(s64)) + sizeof(s64)] 47 ____cacheline_aligned; 48 }; 49 50 enum ad7476_supported_device_ids { 51 ID_AD7091R, 52 ID_AD7276, 53 ID_AD7277, 54 ID_AD7278, 55 ID_AD7466, 56 ID_AD7467, 57 ID_AD7468, 58 ID_AD7495, 59 ID_AD7940, 60 }; 61 62 static irqreturn_t ad7476_trigger_handler(int irq, void *p) 63 { 64 struct iio_poll_func *pf = p; 65 struct iio_dev *indio_dev = pf->indio_dev; 66 struct ad7476_state *st = iio_priv(indio_dev); 67 s64 time_ns; 68 int b_sent; 69 70 b_sent = spi_sync(st->spi, &st->msg); 71 if (b_sent < 0) 72 goto done; 73 74 time_ns = iio_get_time_ns(); 75 76 if (indio_dev->scan_timestamp) 77 ((s64 *)st->data)[1] = time_ns; 78 79 iio_push_to_buffers(indio_dev, st->data); 80 done: 81 iio_trigger_notify_done(indio_dev->trig); 82 83 return IRQ_HANDLED; 84 } 85 86 static void ad7091_reset(struct ad7476_state *st) 87 { 88 /* Any transfers with 8 scl cycles will reset the device */ 89 spi_read(st->spi, st->data, 1); 90 } 91 92 static int ad7476_scan_direct(struct ad7476_state *st) 93 { 94 int ret; 95 96 ret = spi_sync(st->spi, &st->msg); 97 if (ret) 98 return ret; 99 100 return be16_to_cpup((__be16 *)st->data); 101 } 102 103 static int ad7476_read_raw(struct iio_dev *indio_dev, 104 struct iio_chan_spec const *chan, 105 int *val, 106 int *val2, 107 long m) 108 { 109 int ret; 110 struct ad7476_state *st = iio_priv(indio_dev); 111 int scale_uv; 112 113 switch (m) { 114 case IIO_CHAN_INFO_RAW: 115 mutex_lock(&indio_dev->mlock); 116 if (iio_buffer_enabled(indio_dev)) 117 ret = -EBUSY; 118 else 119 ret = ad7476_scan_direct(st); 120 mutex_unlock(&indio_dev->mlock); 121 122 if (ret < 0) 123 return ret; 124 *val = (ret >> st->chip_info->channel[0].scan_type.shift) & 125 RES_MASK(st->chip_info->channel[0].scan_type.realbits); 126 return IIO_VAL_INT; 127 case IIO_CHAN_INFO_SCALE: 128 if (!st->chip_info->int_vref_uv) { 129 scale_uv = regulator_get_voltage(st->reg); 130 if (scale_uv < 0) 131 return scale_uv; 132 } else { 133 scale_uv = st->chip_info->int_vref_uv; 134 } 135 scale_uv >>= chan->scan_type.realbits; 136 *val = scale_uv / 1000; 137 *val2 = (scale_uv % 1000) * 1000; 138 return IIO_VAL_INT_PLUS_MICRO; 139 } 140 return -EINVAL; 141 } 142 143 #define _AD7476_CHAN(bits, _shift, _info_mask) \ 144 { \ 145 .type = IIO_VOLTAGE, \ 146 .indexed = 1, \ 147 .info_mask = _info_mask | \ 148 IIO_CHAN_INFO_SCALE_SHARED_BIT, \ 149 .scan_type = { \ 150 .sign = 'u', \ 151 .realbits = (bits), \ 152 .storagebits = 16, \ 153 .shift = (_shift), \ 154 .endianness = IIO_BE, \ 155 }, \ 156 } 157 158 #define AD7476_CHAN(bits) _AD7476_CHAN((bits), 13 - (bits), \ 159 IIO_CHAN_INFO_RAW_SEPARATE_BIT) 160 #define AD7940_CHAN(bits) _AD7476_CHAN((bits), 15 - (bits), \ 161 IIO_CHAN_INFO_RAW_SEPARATE_BIT) 162 #define AD7091R_CHAN(bits) _AD7476_CHAN((bits), 16 - (bits), 0) 163 164 static const struct ad7476_chip_info ad7476_chip_info_tbl[] = { 165 [ID_AD7091R] = { 166 .channel[0] = AD7091R_CHAN(12), 167 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1), 168 .reset = ad7091_reset, 169 }, 170 [ID_AD7276] = { 171 .channel[0] = AD7940_CHAN(12), 172 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1), 173 }, 174 [ID_AD7277] = { 175 .channel[0] = AD7940_CHAN(10), 176 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1), 177 }, 178 [ID_AD7278] = { 179 .channel[0] = AD7940_CHAN(8), 180 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1), 181 }, 182 [ID_AD7466] = { 183 .channel[0] = AD7476_CHAN(12), 184 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1), 185 }, 186 [ID_AD7467] = { 187 .channel[0] = AD7476_CHAN(10), 188 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1), 189 }, 190 [ID_AD7468] = { 191 .channel[0] = AD7476_CHAN(8), 192 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1), 193 }, 194 [ID_AD7495] = { 195 .channel[0] = AD7476_CHAN(12), 196 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1), 197 .int_vref_uv = 2500000, 198 }, 199 [ID_AD7940] = { 200 .channel[0] = AD7940_CHAN(14), 201 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1), 202 }, 203 }; 204 205 static const struct iio_info ad7476_info = { 206 .driver_module = THIS_MODULE, 207 .read_raw = &ad7476_read_raw, 208 }; 209 210 static int __devinit ad7476_probe(struct spi_device *spi) 211 { 212 struct ad7476_state *st; 213 struct iio_dev *indio_dev; 214 int ret; 215 216 indio_dev = iio_device_alloc(sizeof(*st)); 217 if (indio_dev == NULL) { 218 ret = -ENOMEM; 219 goto error_ret; 220 } 221 st = iio_priv(indio_dev); 222 st->chip_info = 223 &ad7476_chip_info_tbl[spi_get_device_id(spi)->driver_data]; 224 225 st->reg = regulator_get(&spi->dev, "vcc"); 226 if (IS_ERR(st->reg)) { 227 ret = PTR_ERR(st->reg); 228 goto error_free_dev; 229 } 230 231 ret = regulator_enable(st->reg); 232 if (ret) 233 goto error_put_reg; 234 235 spi_set_drvdata(spi, indio_dev); 236 237 st->spi = spi; 238 239 /* Establish that the iio_dev is a child of the spi device */ 240 indio_dev->dev.parent = &spi->dev; 241 indio_dev->name = spi_get_device_id(spi)->name; 242 indio_dev->modes = INDIO_DIRECT_MODE; 243 indio_dev->channels = st->chip_info->channel; 244 indio_dev->num_channels = 2; 245 indio_dev->info = &ad7476_info; 246 /* Setup default message */ 247 248 st->xfer.rx_buf = &st->data; 249 st->xfer.len = st->chip_info->channel[0].scan_type.storagebits / 8; 250 251 spi_message_init(&st->msg); 252 spi_message_add_tail(&st->xfer, &st->msg); 253 254 ret = iio_triggered_buffer_setup(indio_dev, NULL, 255 &ad7476_trigger_handler, NULL); 256 if (ret) 257 goto error_disable_reg; 258 259 if (st->chip_info->reset) 260 st->chip_info->reset(st); 261 262 ret = iio_device_register(indio_dev); 263 if (ret) 264 goto error_ring_unregister; 265 return 0; 266 267 error_ring_unregister: 268 iio_triggered_buffer_cleanup(indio_dev); 269 error_disable_reg: 270 regulator_disable(st->reg); 271 error_put_reg: 272 regulator_put(st->reg); 273 error_free_dev: 274 iio_device_free(indio_dev); 275 276 error_ret: 277 return ret; 278 } 279 280 static int __devexit ad7476_remove(struct spi_device *spi) 281 { 282 struct iio_dev *indio_dev = spi_get_drvdata(spi); 283 struct ad7476_state *st = iio_priv(indio_dev); 284 285 iio_device_unregister(indio_dev); 286 iio_triggered_buffer_cleanup(indio_dev); 287 regulator_disable(st->reg); 288 regulator_put(st->reg); 289 iio_device_free(indio_dev); 290 291 return 0; 292 } 293 294 static const struct spi_device_id ad7476_id[] = { 295 {"ad7091r", ID_AD7091R}, 296 {"ad7273", ID_AD7277}, 297 {"ad7274", ID_AD7276}, 298 {"ad7276", ID_AD7276}, 299 {"ad7277", ID_AD7277}, 300 {"ad7278", ID_AD7278}, 301 {"ad7466", ID_AD7466}, 302 {"ad7467", ID_AD7467}, 303 {"ad7468", ID_AD7468}, 304 {"ad7475", ID_AD7466}, 305 {"ad7476", ID_AD7466}, 306 {"ad7476a", ID_AD7466}, 307 {"ad7477", ID_AD7467}, 308 {"ad7477a", ID_AD7467}, 309 {"ad7478", ID_AD7468}, 310 {"ad7478a", ID_AD7468}, 311 {"ad7495", ID_AD7495}, 312 {"ad7910", ID_AD7467}, 313 {"ad7920", ID_AD7466}, 314 {"ad7940", ID_AD7940}, 315 {} 316 }; 317 MODULE_DEVICE_TABLE(spi, ad7476_id); 318 319 static struct spi_driver ad7476_driver = { 320 .driver = { 321 .name = "ad7476", 322 .owner = THIS_MODULE, 323 }, 324 .probe = ad7476_probe, 325 .remove = __devexit_p(ad7476_remove), 326 .id_table = ad7476_id, 327 }; 328 module_spi_driver(ad7476_driver); 329 330 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>"); 331 MODULE_DESCRIPTION("Analog Devices AD7476 and similar 1-channel ADCs"); 332 MODULE_LICENSE("GPL v2"); 333