1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * MAX1117/MAX1118/MAX1119 8-bit, dual-channel ADCs driver 4 * 5 * Copyright (c) 2017 Akinobu Mita <akinobu.mita@gmail.com> 6 * 7 * Datasheet: https://datasheets.maximintegrated.com/en/ds/MAX1117-MAX1119.pdf 8 * 9 * SPI interface connections 10 * 11 * SPI MAXIM 12 * Master Direction MAX1117/8/9 13 * ------ --------- ----------- 14 * nCS --> CNVST 15 * SCK --> SCLK 16 * MISO <-- DOUT 17 * ------ --------- ----------- 18 */ 19 20 #include <linux/module.h> 21 #include <linux/spi/spi.h> 22 #include <linux/iio/iio.h> 23 #include <linux/iio/buffer.h> 24 #include <linux/iio/triggered_buffer.h> 25 #include <linux/iio/trigger_consumer.h> 26 #include <linux/regulator/consumer.h> 27 28 enum max1118_id { 29 max1117, 30 max1118, 31 max1119, 32 }; 33 34 struct max1118 { 35 struct spi_device *spi; 36 struct mutex lock; 37 struct regulator *reg; 38 39 u8 data ____cacheline_aligned; 40 }; 41 42 #define MAX1118_CHANNEL(ch) \ 43 { \ 44 .type = IIO_VOLTAGE, \ 45 .indexed = 1, \ 46 .channel = (ch), \ 47 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 48 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ 49 .scan_index = ch, \ 50 .scan_type = { \ 51 .sign = 'u', \ 52 .realbits = 8, \ 53 .storagebits = 8, \ 54 }, \ 55 } 56 57 static const struct iio_chan_spec max1118_channels[] = { 58 MAX1118_CHANNEL(0), 59 MAX1118_CHANNEL(1), 60 IIO_CHAN_SOFT_TIMESTAMP(2), 61 }; 62 63 static int max1118_read(struct spi_device *spi, int channel) 64 { 65 struct iio_dev *indio_dev = spi_get_drvdata(spi); 66 struct max1118 *adc = iio_priv(indio_dev); 67 struct spi_transfer xfers[] = { 68 /* 69 * To select CH1 for conversion, CNVST pin must be brought high 70 * and low for a second time. 71 */ 72 { 73 .len = 0, 74 .delay = { /* > CNVST Low Time 100 ns */ 75 .value = 1, 76 .unit = SPI_DELAY_UNIT_USECS 77 }, 78 .cs_change = 1, 79 }, 80 /* 81 * The acquisition interval begins with the falling edge of 82 * CNVST. The total acquisition and conversion process takes 83 * <7.5us. 84 */ 85 { 86 .len = 0, 87 .delay = { 88 .value = 8, 89 .unit = SPI_DELAY_UNIT_USECS 90 }, 91 }, 92 { 93 .rx_buf = &adc->data, 94 .len = 1, 95 }, 96 }; 97 int ret; 98 99 if (channel == 0) 100 ret = spi_sync_transfer(spi, xfers + 1, 2); 101 else 102 ret = spi_sync_transfer(spi, xfers, 3); 103 104 if (ret) 105 return ret; 106 107 return adc->data; 108 } 109 110 static int max1118_get_vref_mV(struct spi_device *spi) 111 { 112 struct iio_dev *indio_dev = spi_get_drvdata(spi); 113 struct max1118 *adc = iio_priv(indio_dev); 114 const struct spi_device_id *id = spi_get_device_id(spi); 115 int vref_uV; 116 117 switch (id->driver_data) { 118 case max1117: 119 return 2048; 120 case max1119: 121 return 4096; 122 case max1118: 123 vref_uV = regulator_get_voltage(adc->reg); 124 if (vref_uV < 0) 125 return vref_uV; 126 return vref_uV / 1000; 127 } 128 129 return -ENODEV; 130 } 131 132 static int max1118_read_raw(struct iio_dev *indio_dev, 133 struct iio_chan_spec const *chan, 134 int *val, int *val2, long mask) 135 { 136 struct max1118 *adc = iio_priv(indio_dev); 137 138 switch (mask) { 139 case IIO_CHAN_INFO_RAW: 140 mutex_lock(&adc->lock); 141 *val = max1118_read(adc->spi, chan->channel); 142 mutex_unlock(&adc->lock); 143 if (*val < 0) 144 return *val; 145 146 return IIO_VAL_INT; 147 case IIO_CHAN_INFO_SCALE: 148 *val = max1118_get_vref_mV(adc->spi); 149 if (*val < 0) 150 return *val; 151 *val2 = 8; 152 153 return IIO_VAL_FRACTIONAL_LOG2; 154 } 155 156 return -EINVAL; 157 } 158 159 static const struct iio_info max1118_info = { 160 .read_raw = max1118_read_raw, 161 }; 162 163 static irqreturn_t max1118_trigger_handler(int irq, void *p) 164 { 165 struct iio_poll_func *pf = p; 166 struct iio_dev *indio_dev = pf->indio_dev; 167 struct max1118 *adc = iio_priv(indio_dev); 168 u8 data[16] = { }; /* 2x 8-bit ADC data + padding + 8 bytes timestamp */ 169 int scan_index; 170 int i = 0; 171 172 mutex_lock(&adc->lock); 173 174 for_each_set_bit(scan_index, indio_dev->active_scan_mask, 175 indio_dev->masklength) { 176 const struct iio_chan_spec *scan_chan = 177 &indio_dev->channels[scan_index]; 178 int ret = max1118_read(adc->spi, scan_chan->channel); 179 180 if (ret < 0) { 181 dev_warn(&adc->spi->dev, 182 "failed to get conversion data\n"); 183 goto out; 184 } 185 186 data[i] = ret; 187 i++; 188 } 189 iio_push_to_buffers_with_timestamp(indio_dev, data, 190 iio_get_time_ns(indio_dev)); 191 out: 192 mutex_unlock(&adc->lock); 193 194 iio_trigger_notify_done(indio_dev->trig); 195 196 return IRQ_HANDLED; 197 } 198 199 static int max1118_probe(struct spi_device *spi) 200 { 201 struct iio_dev *indio_dev; 202 struct max1118 *adc; 203 const struct spi_device_id *id = spi_get_device_id(spi); 204 int ret; 205 206 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc)); 207 if (!indio_dev) 208 return -ENOMEM; 209 210 adc = iio_priv(indio_dev); 211 adc->spi = spi; 212 mutex_init(&adc->lock); 213 214 if (id->driver_data == max1118) { 215 adc->reg = devm_regulator_get(&spi->dev, "vref"); 216 if (IS_ERR(adc->reg)) { 217 dev_err(&spi->dev, "failed to get vref regulator\n"); 218 return PTR_ERR(adc->reg); 219 } 220 ret = regulator_enable(adc->reg); 221 if (ret) 222 return ret; 223 } 224 225 spi_set_drvdata(spi, indio_dev); 226 227 indio_dev->name = spi_get_device_id(spi)->name; 228 indio_dev->dev.parent = &spi->dev; 229 indio_dev->info = &max1118_info; 230 indio_dev->modes = INDIO_DIRECT_MODE; 231 indio_dev->channels = max1118_channels; 232 indio_dev->num_channels = ARRAY_SIZE(max1118_channels); 233 234 /* 235 * To reinitiate a conversion on CH0, it is necessary to allow for a 236 * conversion to be complete and all of the data to be read out. Once 237 * a conversion has been completed, the MAX1117/MAX1118/MAX1119 will go 238 * into AutoShutdown mode until the next conversion is initiated. 239 */ 240 max1118_read(spi, 0); 241 242 ret = iio_triggered_buffer_setup(indio_dev, NULL, 243 max1118_trigger_handler, NULL); 244 if (ret) 245 goto err_reg_disable; 246 247 ret = iio_device_register(indio_dev); 248 if (ret) 249 goto err_buffer_cleanup; 250 251 return 0; 252 253 err_buffer_cleanup: 254 iio_triggered_buffer_cleanup(indio_dev); 255 err_reg_disable: 256 if (id->driver_data == max1118) 257 regulator_disable(adc->reg); 258 259 return ret; 260 } 261 262 static int max1118_remove(struct spi_device *spi) 263 { 264 struct iio_dev *indio_dev = spi_get_drvdata(spi); 265 struct max1118 *adc = iio_priv(indio_dev); 266 const struct spi_device_id *id = spi_get_device_id(spi); 267 268 iio_device_unregister(indio_dev); 269 iio_triggered_buffer_cleanup(indio_dev); 270 if (id->driver_data == max1118) 271 return regulator_disable(adc->reg); 272 273 return 0; 274 } 275 276 static const struct spi_device_id max1118_id[] = { 277 { "max1117", max1117 }, 278 { "max1118", max1118 }, 279 { "max1119", max1119 }, 280 {} 281 }; 282 MODULE_DEVICE_TABLE(spi, max1118_id); 283 284 #ifdef CONFIG_OF 285 286 static const struct of_device_id max1118_dt_ids[] = { 287 { .compatible = "maxim,max1117" }, 288 { .compatible = "maxim,max1118" }, 289 { .compatible = "maxim,max1119" }, 290 {}, 291 }; 292 MODULE_DEVICE_TABLE(of, max1118_dt_ids); 293 294 #endif 295 296 static struct spi_driver max1118_spi_driver = { 297 .driver = { 298 .name = "max1118", 299 .of_match_table = of_match_ptr(max1118_dt_ids), 300 }, 301 .probe = max1118_probe, 302 .remove = max1118_remove, 303 .id_table = max1118_id, 304 }; 305 module_spi_driver(max1118_spi_driver); 306 307 MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>"); 308 MODULE_DESCRIPTION("MAXIM MAX1117/MAX1118/MAX1119 ADCs driver"); 309 MODULE_LICENSE("GPL v2"); 310