1 // SPDX-License-Identifier: GPL-2.0-only 2 /** 3 * Copyright (C) 2017 Axis Communications AB 4 * 5 * Driver for Texas Instruments' ADC084S021 ADC chip. 6 * Datasheets can be found here: 7 * http://www.ti.com/lit/ds/symlink/adc084s021.pdf 8 */ 9 10 #include <linux/err.h> 11 #include <linux/spi/spi.h> 12 #include <linux/module.h> 13 #include <linux/interrupt.h> 14 #include <linux/iio/iio.h> 15 #include <linux/iio/buffer.h> 16 #include <linux/iio/triggered_buffer.h> 17 #include <linux/iio/trigger_consumer.h> 18 #include <linux/regulator/consumer.h> 19 20 #define ADC084S021_DRIVER_NAME "adc084s021" 21 22 struct adc084s021 { 23 struct spi_device *spi; 24 struct spi_message message; 25 struct spi_transfer spi_trans; 26 struct regulator *reg; 27 struct mutex lock; 28 /* 29 * DMA (thus cache coherency maintenance) requires the 30 * transfer buffers to live in their own cache line. 31 */ 32 u16 tx_buf[4] ____cacheline_aligned; 33 __be16 rx_buf[5]; /* First 16-bits are trash */ 34 }; 35 36 #define ADC084S021_VOLTAGE_CHANNEL(num) \ 37 { \ 38 .type = IIO_VOLTAGE, \ 39 .channel = (num), \ 40 .indexed = 1, \ 41 .scan_index = (num), \ 42 .scan_type = { \ 43 .sign = 'u', \ 44 .realbits = 8, \ 45 .storagebits = 16, \ 46 .shift = 4, \ 47 .endianness = IIO_BE, \ 48 }, \ 49 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 50 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),\ 51 } 52 53 static const struct iio_chan_spec adc084s021_channels[] = { 54 ADC084S021_VOLTAGE_CHANNEL(0), 55 ADC084S021_VOLTAGE_CHANNEL(1), 56 ADC084S021_VOLTAGE_CHANNEL(2), 57 ADC084S021_VOLTAGE_CHANNEL(3), 58 IIO_CHAN_SOFT_TIMESTAMP(4), 59 }; 60 61 /** 62 * Read an ADC channel and return its value. 63 * 64 * @adc: The ADC SPI data. 65 * @data: Buffer for converted data. 66 */ 67 static int adc084s021_adc_conversion(struct adc084s021 *adc, void *data) 68 { 69 int n_words = (adc->spi_trans.len >> 1) - 1; /* Discard first word */ 70 int ret, i = 0; 71 u16 *p = data; 72 73 /* Do the transfer */ 74 ret = spi_sync(adc->spi, &adc->message); 75 if (ret < 0) 76 return ret; 77 78 for (; i < n_words; i++) 79 *(p + i) = adc->rx_buf[i + 1]; 80 81 return ret; 82 } 83 84 static int adc084s021_read_raw(struct iio_dev *indio_dev, 85 struct iio_chan_spec const *channel, int *val, 86 int *val2, long mask) 87 { 88 struct adc084s021 *adc = iio_priv(indio_dev); 89 int ret; 90 91 switch (mask) { 92 case IIO_CHAN_INFO_RAW: 93 ret = iio_device_claim_direct_mode(indio_dev); 94 if (ret < 0) 95 return ret; 96 97 ret = regulator_enable(adc->reg); 98 if (ret) { 99 iio_device_release_direct_mode(indio_dev); 100 return ret; 101 } 102 103 adc->tx_buf[0] = channel->channel << 3; 104 ret = adc084s021_adc_conversion(adc, val); 105 iio_device_release_direct_mode(indio_dev); 106 regulator_disable(adc->reg); 107 if (ret < 0) 108 return ret; 109 110 *val = be16_to_cpu(*val); 111 *val = (*val >> channel->scan_type.shift) & 0xff; 112 113 return IIO_VAL_INT; 114 case IIO_CHAN_INFO_SCALE: 115 ret = regulator_enable(adc->reg); 116 if (ret) 117 return ret; 118 119 ret = regulator_get_voltage(adc->reg); 120 regulator_disable(adc->reg); 121 if (ret < 0) 122 return ret; 123 124 *val = ret / 1000; 125 126 return IIO_VAL_INT; 127 default: 128 return -EINVAL; 129 } 130 } 131 132 /** 133 * Read enabled ADC channels and push data to the buffer. 134 * 135 * @irq: The interrupt number (not used). 136 * @pollfunc: Pointer to the poll func. 137 */ 138 static irqreturn_t adc084s021_buffer_trigger_handler(int irq, void *pollfunc) 139 { 140 struct iio_poll_func *pf = pollfunc; 141 struct iio_dev *indio_dev = pf->indio_dev; 142 struct adc084s021 *adc = iio_priv(indio_dev); 143 __be16 data[8] = {0}; /* 4 * 16-bit words of data + 8 bytes timestamp */ 144 145 mutex_lock(&adc->lock); 146 147 if (adc084s021_adc_conversion(adc, &data) < 0) 148 dev_err(&adc->spi->dev, "Failed to read data\n"); 149 150 iio_push_to_buffers_with_timestamp(indio_dev, data, 151 iio_get_time_ns(indio_dev)); 152 mutex_unlock(&adc->lock); 153 iio_trigger_notify_done(indio_dev->trig); 154 155 return IRQ_HANDLED; 156 } 157 158 static int adc084s021_buffer_preenable(struct iio_dev *indio_dev) 159 { 160 struct adc084s021 *adc = iio_priv(indio_dev); 161 int scan_index; 162 int i = 0; 163 164 for_each_set_bit(scan_index, indio_dev->active_scan_mask, 165 indio_dev->masklength) { 166 const struct iio_chan_spec *channel = 167 &indio_dev->channels[scan_index]; 168 adc->tx_buf[i++] = channel->channel << 3; 169 } 170 adc->spi_trans.len = 2 + (i * sizeof(__be16)); /* Trash + channels */ 171 172 return regulator_enable(adc->reg); 173 } 174 175 static int adc084s021_buffer_postdisable(struct iio_dev *indio_dev) 176 { 177 struct adc084s021 *adc = iio_priv(indio_dev); 178 179 adc->spi_trans.len = 4; /* Trash + single channel */ 180 181 return regulator_disable(adc->reg); 182 } 183 184 static const struct iio_info adc084s021_info = { 185 .read_raw = adc084s021_read_raw, 186 }; 187 188 static const struct iio_buffer_setup_ops adc084s021_buffer_setup_ops = { 189 .preenable = adc084s021_buffer_preenable, 190 .postenable = iio_triggered_buffer_postenable, 191 .predisable = iio_triggered_buffer_predisable, 192 .postdisable = adc084s021_buffer_postdisable, 193 }; 194 195 static int adc084s021_probe(struct spi_device *spi) 196 { 197 struct iio_dev *indio_dev; 198 struct adc084s021 *adc; 199 int ret; 200 201 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc)); 202 if (!indio_dev) { 203 dev_err(&spi->dev, "Failed to allocate IIO device\n"); 204 return -ENOMEM; 205 } 206 207 adc = iio_priv(indio_dev); 208 adc->spi = spi; 209 210 /* Connect the SPI device and the iio dev */ 211 spi_set_drvdata(spi, indio_dev); 212 213 /* Initiate the Industrial I/O device */ 214 indio_dev->dev.parent = &spi->dev; 215 indio_dev->dev.of_node = spi->dev.of_node; 216 indio_dev->name = spi_get_device_id(spi)->name; 217 indio_dev->modes = INDIO_DIRECT_MODE; 218 indio_dev->info = &adc084s021_info; 219 indio_dev->channels = adc084s021_channels; 220 indio_dev->num_channels = ARRAY_SIZE(adc084s021_channels); 221 222 /* Create SPI transfer for channel reads */ 223 adc->spi_trans.tx_buf = adc->tx_buf; 224 adc->spi_trans.rx_buf = adc->rx_buf; 225 adc->spi_trans.len = 4; /* Trash + single channel */ 226 spi_message_init_with_transfers(&adc->message, &adc->spi_trans, 1); 227 228 adc->reg = devm_regulator_get(&spi->dev, "vref"); 229 if (IS_ERR(adc->reg)) 230 return PTR_ERR(adc->reg); 231 232 mutex_init(&adc->lock); 233 234 /* Setup triggered buffer with pollfunction */ 235 ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, NULL, 236 adc084s021_buffer_trigger_handler, 237 &adc084s021_buffer_setup_ops); 238 if (ret) { 239 dev_err(&spi->dev, "Failed to setup triggered buffer\n"); 240 return ret; 241 } 242 243 return devm_iio_device_register(&spi->dev, indio_dev); 244 } 245 246 static const struct of_device_id adc084s021_of_match[] = { 247 { .compatible = "ti,adc084s021", }, 248 {}, 249 }; 250 MODULE_DEVICE_TABLE(of, adc084s021_of_match); 251 252 static const struct spi_device_id adc084s021_id[] = { 253 { ADC084S021_DRIVER_NAME, 0}, 254 {} 255 }; 256 MODULE_DEVICE_TABLE(spi, adc084s021_id); 257 258 static struct spi_driver adc084s021_driver = { 259 .driver = { 260 .name = ADC084S021_DRIVER_NAME, 261 .of_match_table = of_match_ptr(adc084s021_of_match), 262 }, 263 .probe = adc084s021_probe, 264 .id_table = adc084s021_id, 265 }; 266 module_spi_driver(adc084s021_driver); 267 268 MODULE_AUTHOR("Mårten Lindahl <martenli@axis.com>"); 269 MODULE_DESCRIPTION("Texas Instruments ADC084S021"); 270 MODULE_LICENSE("GPL v2"); 271 MODULE_VERSION("1.0"); 272