1/* 2 * AD7298 SPI ADC driver 3 * 4 * Copyright 2011 Analog Devices Inc. 5 * 6 * Licensed under the GPL-2. 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/delay.h> 17#include <linux/module.h> 18 19#include "../iio.h" 20#include "../sysfs.h" 21#include "../buffer.h" 22 23#include "ad7298.h" 24 25static struct iio_chan_spec ad7298_channels[] = { 26 IIO_CHAN(IIO_TEMP, 0, 1, 0, NULL, 0, 0, 27 IIO_CHAN_INFO_SCALE_SEPARATE_BIT, 28 9, AD7298_CH_TEMP, IIO_ST('s', 32, 32, 0), 0), 29 IIO_CHAN(IIO_VOLTAGE, 0, 1, 0, NULL, 0, 0, 30 IIO_CHAN_INFO_SCALE_SHARED_BIT, 31 0, 0, IIO_ST('u', 12, 16, 0), 0), 32 IIO_CHAN(IIO_VOLTAGE, 0, 1, 0, NULL, 1, 0, 33 IIO_CHAN_INFO_SCALE_SHARED_BIT, 34 1, 1, IIO_ST('u', 12, 16, 0), 0), 35 IIO_CHAN(IIO_VOLTAGE, 0, 1, 0, NULL, 2, 0, 36 IIO_CHAN_INFO_SCALE_SHARED_BIT, 37 2, 2, IIO_ST('u', 12, 16, 0), 0), 38 IIO_CHAN(IIO_VOLTAGE, 0, 1, 0, NULL, 3, 0, 39 IIO_CHAN_INFO_SCALE_SHARED_BIT, 40 3, 3, IIO_ST('u', 12, 16, 0), 0), 41 IIO_CHAN(IIO_VOLTAGE, 0, 1, 0, NULL, 4, 0, 42 IIO_CHAN_INFO_SCALE_SHARED_BIT, 43 4, 4, IIO_ST('u', 12, 16, 0), 0), 44 IIO_CHAN(IIO_VOLTAGE, 0, 1, 0, NULL, 5, 0, 45 IIO_CHAN_INFO_SCALE_SHARED_BIT, 46 5, 5, IIO_ST('u', 12, 16, 0), 0), 47 IIO_CHAN(IIO_VOLTAGE, 0, 1, 0, NULL, 6, 0, 48 IIO_CHAN_INFO_SCALE_SHARED_BIT, 49 6, 6, IIO_ST('u', 12, 16, 0), 0), 50 IIO_CHAN(IIO_VOLTAGE, 0, 1, 0, NULL, 7, 0, 51 IIO_CHAN_INFO_SCALE_SHARED_BIT, 52 7, 7, IIO_ST('u', 12, 16, 0), 0), 53 IIO_CHAN_SOFT_TIMESTAMP(8), 54}; 55 56static int ad7298_scan_direct(struct ad7298_state *st, unsigned ch) 57{ 58 int ret; 59 st->tx_buf[0] = cpu_to_be16(AD7298_WRITE | st->ext_ref | 60 (AD7298_CH(0) >> ch)); 61 62 ret = spi_sync(st->spi, &st->scan_single_msg); 63 if (ret) 64 return ret; 65 66 return be16_to_cpu(st->rx_buf[0]); 67} 68 69static int ad7298_scan_temp(struct ad7298_state *st, int *val) 70{ 71 int tmp, ret; 72 __be16 buf; 73 74 buf = cpu_to_be16(AD7298_WRITE | AD7298_TSENSE | 75 AD7298_TAVG | st->ext_ref); 76 77 ret = spi_write(st->spi, (u8 *)&buf, 2); 78 if (ret) 79 return ret; 80 81 buf = cpu_to_be16(0); 82 83 ret = spi_write(st->spi, (u8 *)&buf, 2); 84 if (ret) 85 return ret; 86 87 usleep_range(101, 1000); /* sleep > 100us */ 88 89 ret = spi_read(st->spi, (u8 *)&buf, 2); 90 if (ret) 91 return ret; 92 93 tmp = be16_to_cpu(buf) & RES_MASK(AD7298_BITS); 94 95 /* 96 * One LSB of the ADC corresponds to 0.25 deg C. 97 * The temperature reading is in 12-bit twos complement format 98 */ 99 100 if (tmp & (1 << (AD7298_BITS - 1))) { 101 tmp = (4096 - tmp) * 250; 102 tmp -= (2 * tmp); 103 104 } else { 105 tmp *= 250; /* temperature in milli degrees Celsius */ 106 } 107 108 *val = tmp; 109 110 return 0; 111} 112 113static int ad7298_read_raw(struct iio_dev *indio_dev, 114 struct iio_chan_spec const *chan, 115 int *val, 116 int *val2, 117 long m) 118{ 119 int ret; 120 struct ad7298_state *st = iio_priv(indio_dev); 121 unsigned int scale_uv; 122 123 switch (m) { 124 case 0: 125 mutex_lock(&indio_dev->mlock); 126 if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) { 127 ret = -EBUSY; 128 } else { 129 if (chan->address == AD7298_CH_TEMP) 130 ret = ad7298_scan_temp(st, val); 131 else 132 ret = ad7298_scan_direct(st, chan->address); 133 } 134 mutex_unlock(&indio_dev->mlock); 135 136 if (ret < 0) 137 return ret; 138 139 if (chan->address != AD7298_CH_TEMP) 140 *val = ret & RES_MASK(AD7298_BITS); 141 142 return IIO_VAL_INT; 143 case IIO_CHAN_INFO_SCALE: 144 switch (chan->type) { 145 case IIO_VOLTAGE: 146 scale_uv = (st->int_vref_mv * 1000) >> AD7298_BITS; 147 *val = scale_uv / 1000; 148 *val2 = (scale_uv % 1000) * 1000; 149 return IIO_VAL_INT_PLUS_MICRO; 150 case IIO_TEMP: 151 *val = 1; 152 *val2 = 0; 153 return IIO_VAL_INT_PLUS_MICRO; 154 default: 155 return -EINVAL; 156 } 157 } 158 return -EINVAL; 159} 160 161static const struct iio_info ad7298_info = { 162 .read_raw = &ad7298_read_raw, 163 .driver_module = THIS_MODULE, 164}; 165 166static int __devinit ad7298_probe(struct spi_device *spi) 167{ 168 struct ad7298_platform_data *pdata = spi->dev.platform_data; 169 struct ad7298_state *st; 170 int ret; 171 struct iio_dev *indio_dev = iio_allocate_device(sizeof(*st)); 172 173 if (indio_dev == NULL) 174 return -ENOMEM; 175 176 st = iio_priv(indio_dev); 177 178 st->reg = regulator_get(&spi->dev, "vcc"); 179 if (!IS_ERR(st->reg)) { 180 ret = regulator_enable(st->reg); 181 if (ret) 182 goto error_put_reg; 183 } 184 185 spi_set_drvdata(spi, indio_dev); 186 187 st->spi = spi; 188 189 indio_dev->name = spi_get_device_id(spi)->name; 190 indio_dev->dev.parent = &spi->dev; 191 indio_dev->modes = INDIO_DIRECT_MODE; 192 indio_dev->channels = ad7298_channels; 193 indio_dev->num_channels = ARRAY_SIZE(ad7298_channels); 194 indio_dev->info = &ad7298_info; 195 196 /* Setup default message */ 197 198 st->scan_single_xfer[0].tx_buf = &st->tx_buf[0]; 199 st->scan_single_xfer[0].len = 2; 200 st->scan_single_xfer[0].cs_change = 1; 201 st->scan_single_xfer[1].tx_buf = &st->tx_buf[1]; 202 st->scan_single_xfer[1].len = 2; 203 st->scan_single_xfer[1].cs_change = 1; 204 st->scan_single_xfer[2].rx_buf = &st->rx_buf[0]; 205 st->scan_single_xfer[2].len = 2; 206 207 spi_message_init(&st->scan_single_msg); 208 spi_message_add_tail(&st->scan_single_xfer[0], &st->scan_single_msg); 209 spi_message_add_tail(&st->scan_single_xfer[1], &st->scan_single_msg); 210 spi_message_add_tail(&st->scan_single_xfer[2], &st->scan_single_msg); 211 212 if (pdata && pdata->vref_mv) { 213 st->int_vref_mv = pdata->vref_mv; 214 st->ext_ref = AD7298_EXTREF; 215 } else { 216 st->int_vref_mv = AD7298_INTREF_mV; 217 } 218 219 ret = ad7298_register_ring_funcs_and_init(indio_dev); 220 if (ret) 221 goto error_disable_reg; 222 223 ret = iio_buffer_register(indio_dev, 224 &ad7298_channels[1], /* skip temp0 */ 225 ARRAY_SIZE(ad7298_channels) - 1); 226 if (ret) 227 goto error_cleanup_ring; 228 ret = iio_device_register(indio_dev); 229 if (ret) 230 goto error_unregister_ring; 231 232 return 0; 233 234error_unregister_ring: 235 iio_buffer_unregister(indio_dev); 236error_cleanup_ring: 237 ad7298_ring_cleanup(indio_dev); 238error_disable_reg: 239 if (!IS_ERR(st->reg)) 240 regulator_disable(st->reg); 241error_put_reg: 242 if (!IS_ERR(st->reg)) 243 regulator_put(st->reg); 244 iio_free_device(indio_dev); 245 246 return ret; 247} 248 249static int __devexit ad7298_remove(struct spi_device *spi) 250{ 251 struct iio_dev *indio_dev = spi_get_drvdata(spi); 252 struct ad7298_state *st = iio_priv(indio_dev); 253 254 iio_device_unregister(indio_dev); 255 iio_buffer_unregister(indio_dev); 256 ad7298_ring_cleanup(indio_dev); 257 if (!IS_ERR(st->reg)) { 258 regulator_disable(st->reg); 259 regulator_put(st->reg); 260 } 261 iio_free_device(indio_dev); 262 263 return 0; 264} 265 266static const struct spi_device_id ad7298_id[] = { 267 {"ad7298", 0}, 268 {} 269}; 270MODULE_DEVICE_TABLE(spi, ad7298_id); 271 272static struct spi_driver ad7298_driver = { 273 .driver = { 274 .name = "ad7298", 275 .owner = THIS_MODULE, 276 }, 277 .probe = ad7298_probe, 278 .remove = __devexit_p(ad7298_remove), 279 .id_table = ad7298_id, 280}; 281module_spi_driver(ad7298_driver); 282 283MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>"); 284MODULE_DESCRIPTION("Analog Devices AD7298 ADC"); 285MODULE_LICENSE("GPL v2"); 286