1 /* 2 * AD7766/AD7767 SPI ADC driver 3 * 4 * Copyright 2016 Analog Devices Inc. 5 * 6 * Licensed under the GPL-2 or later. 7 */ 8 9 #include <linux/clk.h> 10 #include <linux/delay.h> 11 #include <linux/device.h> 12 #include <linux/err.h> 13 #include <linux/gpio/consumer.h> 14 #include <linux/module.h> 15 #include <linux/regulator/consumer.h> 16 #include <linux/slab.h> 17 #include <linux/spi/spi.h> 18 19 #include <linux/iio/iio.h> 20 #include <linux/iio/buffer.h> 21 #include <linux/iio/trigger.h> 22 #include <linux/iio/trigger_consumer.h> 23 #include <linux/iio/triggered_buffer.h> 24 25 struct ad7766_chip_info { 26 unsigned int decimation_factor; 27 }; 28 29 enum { 30 AD7766_SUPPLY_AVDD = 0, 31 AD7766_SUPPLY_DVDD = 1, 32 AD7766_SUPPLY_VREF = 2, 33 AD7766_NUM_SUPPLIES = 3 34 }; 35 36 struct ad7766 { 37 const struct ad7766_chip_info *chip_info; 38 struct spi_device *spi; 39 struct clk *mclk; 40 struct gpio_desc *pd_gpio; 41 struct regulator_bulk_data reg[AD7766_NUM_SUPPLIES]; 42 43 struct iio_trigger *trig; 44 45 struct spi_transfer xfer; 46 struct spi_message msg; 47 48 /* 49 * DMA (thus cache coherency maintenance) requires the 50 * transfer buffers to live in their own cache lines. 51 * Make the buffer large enough for one 24 bit sample and one 64 bit 52 * aligned 64 bit timestamp. 53 */ 54 unsigned char data[ALIGN(3, sizeof(s64)) + sizeof(s64)] 55 ____cacheline_aligned; 56 }; 57 58 /* 59 * AD7766 and AD7767 variations are interface compatible, the main difference is 60 * analog performance. Both parts will use the same ID. 61 */ 62 enum ad7766_device_ids { 63 ID_AD7766, 64 ID_AD7766_1, 65 ID_AD7766_2, 66 }; 67 68 static irqreturn_t ad7766_trigger_handler(int irq, void *p) 69 { 70 struct iio_poll_func *pf = p; 71 struct iio_dev *indio_dev = pf->indio_dev; 72 struct ad7766 *ad7766 = iio_priv(indio_dev); 73 int ret; 74 75 ret = spi_sync(ad7766->spi, &ad7766->msg); 76 if (ret < 0) 77 goto done; 78 79 iio_push_to_buffers_with_timestamp(indio_dev, ad7766->data, 80 pf->timestamp); 81 done: 82 iio_trigger_notify_done(indio_dev->trig); 83 84 return IRQ_HANDLED; 85 } 86 87 static int ad7766_preenable(struct iio_dev *indio_dev) 88 { 89 struct ad7766 *ad7766 = iio_priv(indio_dev); 90 int ret; 91 92 ret = regulator_bulk_enable(ARRAY_SIZE(ad7766->reg), ad7766->reg); 93 if (ret < 0) { 94 dev_err(&ad7766->spi->dev, "Failed to enable supplies: %d\n", 95 ret); 96 return ret; 97 } 98 99 ret = clk_prepare_enable(ad7766->mclk); 100 if (ret < 0) { 101 dev_err(&ad7766->spi->dev, "Failed to enable MCLK: %d\n", ret); 102 regulator_bulk_disable(ARRAY_SIZE(ad7766->reg), ad7766->reg); 103 return ret; 104 } 105 106 if (ad7766->pd_gpio) 107 gpiod_set_value(ad7766->pd_gpio, 0); 108 109 return 0; 110 } 111 112 static int ad7766_postdisable(struct iio_dev *indio_dev) 113 { 114 struct ad7766 *ad7766 = iio_priv(indio_dev); 115 116 if (ad7766->pd_gpio) 117 gpiod_set_value(ad7766->pd_gpio, 1); 118 119 /* 120 * The PD pin is synchronous to the clock, so give it some time to 121 * notice the change before we disable the clock. 122 */ 123 msleep(20); 124 125 clk_disable_unprepare(ad7766->mclk); 126 regulator_bulk_disable(ARRAY_SIZE(ad7766->reg), ad7766->reg); 127 128 return 0; 129 } 130 131 static int ad7766_read_raw(struct iio_dev *indio_dev, 132 const struct iio_chan_spec *chan, int *val, int *val2, long info) 133 { 134 struct ad7766 *ad7766 = iio_priv(indio_dev); 135 struct regulator *vref = ad7766->reg[AD7766_SUPPLY_VREF].consumer; 136 int scale_uv; 137 138 switch (info) { 139 case IIO_CHAN_INFO_SCALE: 140 scale_uv = regulator_get_voltage(vref); 141 if (scale_uv < 0) 142 return scale_uv; 143 *val = scale_uv / 1000; 144 *val2 = chan->scan_type.realbits; 145 return IIO_VAL_FRACTIONAL_LOG2; 146 case IIO_CHAN_INFO_SAMP_FREQ: 147 *val = clk_get_rate(ad7766->mclk) / 148 ad7766->chip_info->decimation_factor; 149 return IIO_VAL_INT; 150 } 151 return -EINVAL; 152 } 153 154 static const struct iio_chan_spec ad7766_channels[] = { 155 { 156 .type = IIO_VOLTAGE, 157 .indexed = 1, 158 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), 159 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), 160 .scan_type = { 161 .sign = 's', 162 .realbits = 24, 163 .storagebits = 32, 164 .endianness = IIO_BE, 165 }, 166 }, 167 IIO_CHAN_SOFT_TIMESTAMP(1), 168 }; 169 170 static const struct ad7766_chip_info ad7766_chip_info[] = { 171 [ID_AD7766] = { 172 .decimation_factor = 8, 173 }, 174 [ID_AD7766_1] = { 175 .decimation_factor = 16, 176 }, 177 [ID_AD7766_2] = { 178 .decimation_factor = 32, 179 }, 180 }; 181 182 static const struct iio_buffer_setup_ops ad7766_buffer_setup_ops = { 183 .preenable = &ad7766_preenable, 184 .postenable = &iio_triggered_buffer_postenable, 185 .predisable = &iio_triggered_buffer_predisable, 186 .postdisable = &ad7766_postdisable, 187 }; 188 189 static const struct iio_info ad7766_info = { 190 .driver_module = THIS_MODULE, 191 .read_raw = &ad7766_read_raw, 192 }; 193 194 static irqreturn_t ad7766_irq(int irq, void *private) 195 { 196 iio_trigger_poll(private); 197 return IRQ_HANDLED; 198 } 199 200 static int ad7766_set_trigger_state(struct iio_trigger *trig, bool enable) 201 { 202 struct ad7766 *ad7766 = iio_trigger_get_drvdata(trig); 203 204 if (enable) 205 enable_irq(ad7766->spi->irq); 206 else 207 disable_irq(ad7766->spi->irq); 208 209 return 0; 210 } 211 212 static const struct iio_trigger_ops ad7766_trigger_ops = { 213 .owner = THIS_MODULE, 214 .set_trigger_state = ad7766_set_trigger_state, 215 .validate_device = iio_trigger_validate_own_device, 216 }; 217 218 static int ad7766_probe(struct spi_device *spi) 219 { 220 const struct spi_device_id *id = spi_get_device_id(spi); 221 struct iio_dev *indio_dev; 222 struct ad7766 *ad7766; 223 int ret; 224 225 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*ad7766)); 226 if (!indio_dev) 227 return -ENOMEM; 228 229 ad7766 = iio_priv(indio_dev); 230 ad7766->chip_info = &ad7766_chip_info[id->driver_data]; 231 232 ad7766->mclk = devm_clk_get(&spi->dev, "mclk"); 233 if (IS_ERR(ad7766->mclk)) 234 return PTR_ERR(ad7766->mclk); 235 236 ad7766->reg[AD7766_SUPPLY_AVDD].supply = "avdd"; 237 ad7766->reg[AD7766_SUPPLY_DVDD].supply = "dvdd"; 238 ad7766->reg[AD7766_SUPPLY_VREF].supply = "vref"; 239 240 ret = devm_regulator_bulk_get(&spi->dev, ARRAY_SIZE(ad7766->reg), 241 ad7766->reg); 242 if (ret) 243 return ret; 244 245 ad7766->pd_gpio = devm_gpiod_get_optional(&spi->dev, "powerdown", 246 GPIOD_OUT_HIGH); 247 if (IS_ERR(ad7766->pd_gpio)) 248 return PTR_ERR(ad7766->pd_gpio); 249 250 indio_dev->dev.parent = &spi->dev; 251 indio_dev->name = spi_get_device_id(spi)->name; 252 indio_dev->modes = INDIO_DIRECT_MODE; 253 indio_dev->channels = ad7766_channels; 254 indio_dev->num_channels = ARRAY_SIZE(ad7766_channels); 255 indio_dev->info = &ad7766_info; 256 257 if (spi->irq > 0) { 258 ad7766->trig = devm_iio_trigger_alloc(&spi->dev, "%s-dev%d", 259 indio_dev->name, indio_dev->id); 260 if (!ad7766->trig) 261 return -ENOMEM; 262 263 ad7766->trig->ops = &ad7766_trigger_ops; 264 ad7766->trig->dev.parent = &spi->dev; 265 iio_trigger_set_drvdata(ad7766->trig, ad7766); 266 267 ret = devm_request_irq(&spi->dev, spi->irq, ad7766_irq, 268 IRQF_TRIGGER_FALLING, dev_name(&spi->dev), 269 ad7766->trig); 270 if (ret < 0) 271 return ret; 272 273 /* 274 * The device generates interrupts as long as it is powered up. 275 * Some platforms might not allow the option to power it down so 276 * disable the interrupt to avoid extra load on the system 277 */ 278 disable_irq(spi->irq); 279 280 ret = devm_iio_trigger_register(&spi->dev, ad7766->trig); 281 if (ret) 282 return ret; 283 } 284 285 spi_set_drvdata(spi, indio_dev); 286 287 ad7766->spi = spi; 288 289 /* First byte always 0 */ 290 ad7766->xfer.rx_buf = &ad7766->data[1]; 291 ad7766->xfer.len = 3; 292 293 spi_message_init(&ad7766->msg); 294 spi_message_add_tail(&ad7766->xfer, &ad7766->msg); 295 296 ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, 297 &iio_pollfunc_store_time, &ad7766_trigger_handler, 298 &ad7766_buffer_setup_ops); 299 if (ret) 300 return ret; 301 302 ret = devm_iio_device_register(&spi->dev, indio_dev); 303 if (ret) 304 return ret; 305 return 0; 306 } 307 308 static const struct spi_device_id ad7766_id[] = { 309 {"ad7766", ID_AD7766}, 310 {"ad7766-1", ID_AD7766_1}, 311 {"ad7766-2", ID_AD7766_2}, 312 {"ad7767", ID_AD7766}, 313 {"ad7767-1", ID_AD7766_1}, 314 {"ad7767-2", ID_AD7766_2}, 315 {} 316 }; 317 MODULE_DEVICE_TABLE(spi, ad7766_id); 318 319 static struct spi_driver ad7766_driver = { 320 .driver = { 321 .name = "ad7766", 322 }, 323 .probe = ad7766_probe, 324 .id_table = ad7766_id, 325 }; 326 module_spi_driver(ad7766_driver); 327 328 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); 329 MODULE_DESCRIPTION("Analog Devices AD7766 and AD7767 ADCs driver support"); 330 MODULE_LICENSE("GPL v2"); 331