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 gpiod_set_value(ad7766->pd_gpio, 0); 107 108 return 0; 109 } 110 111 static int ad7766_postdisable(struct iio_dev *indio_dev) 112 { 113 struct ad7766 *ad7766 = iio_priv(indio_dev); 114 115 gpiod_set_value(ad7766->pd_gpio, 1); 116 117 /* 118 * The PD pin is synchronous to the clock, so give it some time to 119 * notice the change before we disable the clock. 120 */ 121 msleep(20); 122 123 clk_disable_unprepare(ad7766->mclk); 124 regulator_bulk_disable(ARRAY_SIZE(ad7766->reg), ad7766->reg); 125 126 return 0; 127 } 128 129 static int ad7766_read_raw(struct iio_dev *indio_dev, 130 const struct iio_chan_spec *chan, int *val, int *val2, long info) 131 { 132 struct ad7766 *ad7766 = iio_priv(indio_dev); 133 struct regulator *vref = ad7766->reg[AD7766_SUPPLY_VREF].consumer; 134 int scale_uv; 135 136 switch (info) { 137 case IIO_CHAN_INFO_SCALE: 138 scale_uv = regulator_get_voltage(vref); 139 if (scale_uv < 0) 140 return scale_uv; 141 *val = scale_uv / 1000; 142 *val2 = chan->scan_type.realbits; 143 return IIO_VAL_FRACTIONAL_LOG2; 144 case IIO_CHAN_INFO_SAMP_FREQ: 145 *val = clk_get_rate(ad7766->mclk) / 146 ad7766->chip_info->decimation_factor; 147 return IIO_VAL_INT; 148 } 149 return -EINVAL; 150 } 151 152 static const struct iio_chan_spec ad7766_channels[] = { 153 { 154 .type = IIO_VOLTAGE, 155 .indexed = 1, 156 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), 157 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), 158 .scan_type = { 159 .sign = 's', 160 .realbits = 24, 161 .storagebits = 32, 162 .endianness = IIO_BE, 163 }, 164 }, 165 IIO_CHAN_SOFT_TIMESTAMP(1), 166 }; 167 168 static const struct ad7766_chip_info ad7766_chip_info[] = { 169 [ID_AD7766] = { 170 .decimation_factor = 8, 171 }, 172 [ID_AD7766_1] = { 173 .decimation_factor = 16, 174 }, 175 [ID_AD7766_2] = { 176 .decimation_factor = 32, 177 }, 178 }; 179 180 static const struct iio_buffer_setup_ops ad7766_buffer_setup_ops = { 181 .preenable = &ad7766_preenable, 182 .postenable = &iio_triggered_buffer_postenable, 183 .predisable = &iio_triggered_buffer_predisable, 184 .postdisable = &ad7766_postdisable, 185 }; 186 187 static const struct iio_info ad7766_info = { 188 .read_raw = &ad7766_read_raw, 189 }; 190 191 static irqreturn_t ad7766_irq(int irq, void *private) 192 { 193 iio_trigger_poll(private); 194 return IRQ_HANDLED; 195 } 196 197 static int ad7766_set_trigger_state(struct iio_trigger *trig, bool enable) 198 { 199 struct ad7766 *ad7766 = iio_trigger_get_drvdata(trig); 200 201 if (enable) 202 enable_irq(ad7766->spi->irq); 203 else 204 disable_irq(ad7766->spi->irq); 205 206 return 0; 207 } 208 209 static const struct iio_trigger_ops ad7766_trigger_ops = { 210 .set_trigger_state = ad7766_set_trigger_state, 211 .validate_device = iio_trigger_validate_own_device, 212 }; 213 214 static int ad7766_probe(struct spi_device *spi) 215 { 216 const struct spi_device_id *id = spi_get_device_id(spi); 217 struct iio_dev *indio_dev; 218 struct ad7766 *ad7766; 219 int ret; 220 221 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*ad7766)); 222 if (!indio_dev) 223 return -ENOMEM; 224 225 ad7766 = iio_priv(indio_dev); 226 ad7766->chip_info = &ad7766_chip_info[id->driver_data]; 227 228 ad7766->mclk = devm_clk_get(&spi->dev, "mclk"); 229 if (IS_ERR(ad7766->mclk)) 230 return PTR_ERR(ad7766->mclk); 231 232 ad7766->reg[AD7766_SUPPLY_AVDD].supply = "avdd"; 233 ad7766->reg[AD7766_SUPPLY_DVDD].supply = "dvdd"; 234 ad7766->reg[AD7766_SUPPLY_VREF].supply = "vref"; 235 236 ret = devm_regulator_bulk_get(&spi->dev, ARRAY_SIZE(ad7766->reg), 237 ad7766->reg); 238 if (ret) 239 return ret; 240 241 ad7766->pd_gpio = devm_gpiod_get_optional(&spi->dev, "powerdown", 242 GPIOD_OUT_HIGH); 243 if (IS_ERR(ad7766->pd_gpio)) 244 return PTR_ERR(ad7766->pd_gpio); 245 246 indio_dev->dev.parent = &spi->dev; 247 indio_dev->name = spi_get_device_id(spi)->name; 248 indio_dev->modes = INDIO_DIRECT_MODE; 249 indio_dev->channels = ad7766_channels; 250 indio_dev->num_channels = ARRAY_SIZE(ad7766_channels); 251 indio_dev->info = &ad7766_info; 252 253 if (spi->irq > 0) { 254 ad7766->trig = devm_iio_trigger_alloc(&spi->dev, "%s-dev%d", 255 indio_dev->name, indio_dev->id); 256 if (!ad7766->trig) 257 return -ENOMEM; 258 259 ad7766->trig->ops = &ad7766_trigger_ops; 260 ad7766->trig->dev.parent = &spi->dev; 261 iio_trigger_set_drvdata(ad7766->trig, ad7766); 262 263 ret = devm_request_irq(&spi->dev, spi->irq, ad7766_irq, 264 IRQF_TRIGGER_FALLING, dev_name(&spi->dev), 265 ad7766->trig); 266 if (ret < 0) 267 return ret; 268 269 /* 270 * The device generates interrupts as long as it is powered up. 271 * Some platforms might not allow the option to power it down so 272 * disable the interrupt to avoid extra load on the system 273 */ 274 disable_irq(spi->irq); 275 276 ret = devm_iio_trigger_register(&spi->dev, ad7766->trig); 277 if (ret) 278 return ret; 279 } 280 281 spi_set_drvdata(spi, indio_dev); 282 283 ad7766->spi = spi; 284 285 /* First byte always 0 */ 286 ad7766->xfer.rx_buf = &ad7766->data[1]; 287 ad7766->xfer.len = 3; 288 289 spi_message_init(&ad7766->msg); 290 spi_message_add_tail(&ad7766->xfer, &ad7766->msg); 291 292 ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, 293 &iio_pollfunc_store_time, &ad7766_trigger_handler, 294 &ad7766_buffer_setup_ops); 295 if (ret) 296 return ret; 297 298 ret = devm_iio_device_register(&spi->dev, indio_dev); 299 if (ret) 300 return ret; 301 return 0; 302 } 303 304 static const struct spi_device_id ad7766_id[] = { 305 {"ad7766", ID_AD7766}, 306 {"ad7766-1", ID_AD7766_1}, 307 {"ad7766-2", ID_AD7766_2}, 308 {"ad7767", ID_AD7766}, 309 {"ad7767-1", ID_AD7766_1}, 310 {"ad7767-2", ID_AD7766_2}, 311 {} 312 }; 313 MODULE_DEVICE_TABLE(spi, ad7766_id); 314 315 static struct spi_driver ad7766_driver = { 316 .driver = { 317 .name = "ad7766", 318 }, 319 .probe = ad7766_probe, 320 .id_table = ad7766_id, 321 }; 322 module_spi_driver(ad7766_driver); 323 324 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); 325 MODULE_DESCRIPTION("Analog Devices AD7766 and AD7767 ADCs driver support"); 326 MODULE_LICENSE("GPL v2"); 327