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 * https://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/mod_devicetable.h> 14 #include <linux/interrupt.h> 15 #include <linux/iio/iio.h> 16 #include <linux/iio/buffer.h> 17 #include <linux/iio/triggered_buffer.h> 18 #include <linux/iio/trigger_consumer.h> 19 #include <linux/regulator/consumer.h> 20 21 #define ADC084S021_DRIVER_NAME "adc084s021" 22 23 struct adc084s021 { 24 struct spi_device *spi; 25 struct spi_message message; 26 struct spi_transfer spi_trans; 27 struct regulator *reg; 28 struct mutex lock; 29 /* Buffer used to align data */ 30 struct { 31 __be16 channels[4]; 32 aligned_s64 ts; 33 } scan; 34 /* 35 * DMA (thus cache coherency maintenance) may require the 36 * transfer buffers to live in their own cache line. 37 */ 38 u16 tx_buf[4] __aligned(IIO_DMA_MINALIGN); 39 __be16 rx_buf[5]; /* First 16-bits are trash */ 40 }; 41 42 #define ADC084S021_VOLTAGE_CHANNEL(num) \ 43 { \ 44 .type = IIO_VOLTAGE, \ 45 .channel = (num), \ 46 .indexed = 1, \ 47 .scan_index = (num), \ 48 .scan_type = { \ 49 .sign = 'u', \ 50 .realbits = 8, \ 51 .storagebits = 16, \ 52 .shift = 4, \ 53 .endianness = IIO_BE, \ 54 }, \ 55 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 56 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),\ 57 } 58 59 static const struct iio_chan_spec adc084s021_channels[] = { 60 ADC084S021_VOLTAGE_CHANNEL(0), 61 ADC084S021_VOLTAGE_CHANNEL(1), 62 ADC084S021_VOLTAGE_CHANNEL(2), 63 ADC084S021_VOLTAGE_CHANNEL(3), 64 IIO_CHAN_SOFT_TIMESTAMP(4), 65 }; 66 67 /** 68 * adc084s021_adc_conversion() - Read an ADC channel and return its value. 69 * 70 * @adc: The ADC SPI data. 71 * @data: Buffer for converted data. 72 */ 73 static int adc084s021_adc_conversion(struct adc084s021 *adc, __be16 *data) 74 { 75 int n_words = (adc->spi_trans.len >> 1) - 1; /* Discard first word */ 76 int ret, i = 0; 77 78 /* Do the transfer */ 79 ret = spi_sync(adc->spi, &adc->message); 80 if (ret < 0) 81 return ret; 82 83 for (; i < n_words; i++) 84 *(data + i) = adc->rx_buf[i + 1]; 85 86 return ret; 87 } 88 89 static int adc084s021_read_raw(struct iio_dev *indio_dev, 90 struct iio_chan_spec const *channel, int *val, 91 int *val2, long mask) 92 { 93 struct adc084s021 *adc = iio_priv(indio_dev); 94 int ret; 95 __be16 be_val; 96 97 switch (mask) { 98 case IIO_CHAN_INFO_RAW: 99 if (!iio_device_claim_direct(indio_dev)) 100 return -EBUSY; 101 102 ret = regulator_enable(adc->reg); 103 if (ret) { 104 iio_device_release_direct(indio_dev); 105 return ret; 106 } 107 108 adc->tx_buf[0] = channel->channel << 3; 109 ret = adc084s021_adc_conversion(adc, &be_val); 110 iio_device_release_direct(indio_dev); 111 regulator_disable(adc->reg); 112 if (ret < 0) 113 return ret; 114 115 *val = be16_to_cpu(be_val); 116 *val = (*val >> channel->scan_type.shift) & 0xff; 117 118 return IIO_VAL_INT; 119 case IIO_CHAN_INFO_SCALE: 120 ret = regulator_enable(adc->reg); 121 if (ret) 122 return ret; 123 124 ret = regulator_get_voltage(adc->reg); 125 regulator_disable(adc->reg); 126 if (ret < 0) 127 return ret; 128 129 *val = ret / 1000; 130 131 return IIO_VAL_INT; 132 default: 133 return -EINVAL; 134 } 135 } 136 137 /** 138 * adc084s021_buffer_trigger_handler() - Read ADC channels and push to buffer. 139 * 140 * @irq: The interrupt number (not used). 141 * @pollfunc: Pointer to the poll func. 142 */ 143 static irqreturn_t adc084s021_buffer_trigger_handler(int irq, void *pollfunc) 144 { 145 struct iio_poll_func *pf = pollfunc; 146 struct iio_dev *indio_dev = pf->indio_dev; 147 struct adc084s021 *adc = iio_priv(indio_dev); 148 149 mutex_lock(&adc->lock); 150 151 if (adc084s021_adc_conversion(adc, adc->scan.channels) < 0) 152 dev_err(&adc->spi->dev, "Failed to read data\n"); 153 154 iio_push_to_buffers_with_ts(indio_dev, &adc->scan, sizeof(adc->scan), 155 iio_get_time_ns(indio_dev)); 156 mutex_unlock(&adc->lock); 157 iio_trigger_notify_done(indio_dev->trig); 158 159 return IRQ_HANDLED; 160 } 161 162 static int adc084s021_buffer_preenable(struct iio_dev *indio_dev) 163 { 164 struct adc084s021 *adc = iio_priv(indio_dev); 165 int scan_index; 166 int i = 0; 167 168 iio_for_each_active_channel(indio_dev, scan_index) { 169 const struct iio_chan_spec *channel = 170 &indio_dev->channels[scan_index]; 171 adc->tx_buf[i++] = channel->channel << 3; 172 } 173 adc->spi_trans.len = 2 + (i * sizeof(__be16)); /* Trash + channels */ 174 175 return regulator_enable(adc->reg); 176 } 177 178 static int adc084s021_buffer_postdisable(struct iio_dev *indio_dev) 179 { 180 struct adc084s021 *adc = iio_priv(indio_dev); 181 182 adc->spi_trans.len = 4; /* Trash + single channel */ 183 184 return regulator_disable(adc->reg); 185 } 186 187 static const struct iio_info adc084s021_info = { 188 .read_raw = adc084s021_read_raw, 189 }; 190 191 static const struct iio_buffer_setup_ops adc084s021_buffer_setup_ops = { 192 .preenable = adc084s021_buffer_preenable, 193 .postdisable = adc084s021_buffer_postdisable, 194 }; 195 196 static int adc084s021_probe(struct spi_device *spi) 197 { 198 struct iio_dev *indio_dev; 199 struct adc084s021 *adc; 200 int ret; 201 202 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc)); 203 if (!indio_dev) { 204 dev_err(&spi->dev, "Failed to allocate IIO device\n"); 205 return -ENOMEM; 206 } 207 208 adc = iio_priv(indio_dev); 209 adc->spi = spi; 210 211 /* Initiate the Industrial I/O device */ 212 indio_dev->name = spi_get_device_id(spi)->name; 213 indio_dev->modes = INDIO_DIRECT_MODE; 214 indio_dev->info = &adc084s021_info; 215 indio_dev->channels = adc084s021_channels; 216 indio_dev->num_channels = ARRAY_SIZE(adc084s021_channels); 217 218 /* Create SPI transfer for channel reads */ 219 adc->spi_trans.tx_buf = adc->tx_buf; 220 adc->spi_trans.rx_buf = adc->rx_buf; 221 adc->spi_trans.len = 4; /* Trash + single channel */ 222 spi_message_init_with_transfers(&adc->message, &adc->spi_trans, 1); 223 224 adc->reg = devm_regulator_get(&spi->dev, "vref"); 225 if (IS_ERR(adc->reg)) 226 return PTR_ERR(adc->reg); 227 228 mutex_init(&adc->lock); 229 230 /* Setup triggered buffer with pollfunction */ 231 ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, NULL, 232 adc084s021_buffer_trigger_handler, 233 &adc084s021_buffer_setup_ops); 234 if (ret) { 235 dev_err(&spi->dev, "Failed to setup triggered buffer\n"); 236 return ret; 237 } 238 239 return devm_iio_device_register(&spi->dev, indio_dev); 240 } 241 242 static const struct of_device_id adc084s021_of_match[] = { 243 { .compatible = "ti,adc084s021", }, 244 { } 245 }; 246 MODULE_DEVICE_TABLE(of, adc084s021_of_match); 247 248 static const struct spi_device_id adc084s021_id[] = { 249 { ADC084S021_DRIVER_NAME, 0 }, 250 { } 251 }; 252 MODULE_DEVICE_TABLE(spi, adc084s021_id); 253 254 static struct spi_driver adc084s021_driver = { 255 .driver = { 256 .name = ADC084S021_DRIVER_NAME, 257 .of_match_table = adc084s021_of_match, 258 }, 259 .probe = adc084s021_probe, 260 .id_table = adc084s021_id, 261 }; 262 module_spi_driver(adc084s021_driver); 263 264 MODULE_AUTHOR("Mårten Lindahl <martenli@axis.com>"); 265 MODULE_DESCRIPTION("Texas Instruments ADC084S021"); 266 MODULE_LICENSE("GPL v2"); 267 MODULE_VERSION("1.0"); 268