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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright (C) 2017 Axis Communications AB4 *5 * Driver for Texas Instruments' ADC084S021 ADC chip.6 * Datasheets can be found here:7 * https://www.ti.com/lit/ds/symlink/adc084s021.pdf8 */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 23struct 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 s64 ts __aligned(8);33 } scan;34 /*35 * DMA (thus cache coherency maintenance) may require the36 * 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 59static 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 */73static 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 89static 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 ret = iio_device_claim_direct_mode(indio_dev);100 if (ret < 0)101 return ret;102 103 ret = regulator_enable(adc->reg);104 if (ret) {105 iio_device_release_direct_mode(indio_dev);106 return ret;107 }108 109 adc->tx_buf[0] = channel->channel << 3;110 ret = adc084s021_adc_conversion(adc, &be_val);111 iio_device_release_direct_mode(indio_dev);112 regulator_disable(adc->reg);113 if (ret < 0)114 return ret;115 116 *val = be16_to_cpu(be_val);117 *val = (*val >> channel->scan_type.shift) & 0xff;118 119 return IIO_VAL_INT;120 case IIO_CHAN_INFO_SCALE:121 ret = regulator_enable(adc->reg);122 if (ret)123 return ret;124 125 ret = regulator_get_voltage(adc->reg);126 regulator_disable(adc->reg);127 if (ret < 0)128 return ret;129 130 *val = ret / 1000;131 132 return IIO_VAL_INT;133 default:134 return -EINVAL;135 }136}137 138/**139 * adc084s021_buffer_trigger_handler() - Read ADC channels and push to buffer.140 *141 * @irq: The interrupt number (not used).142 * @pollfunc: Pointer to the poll func.143 */144static irqreturn_t adc084s021_buffer_trigger_handler(int irq, void *pollfunc)145{146 struct iio_poll_func *pf = pollfunc;147 struct iio_dev *indio_dev = pf->indio_dev;148 struct adc084s021 *adc = iio_priv(indio_dev);149 150 mutex_lock(&adc->lock);151 152 if (adc084s021_adc_conversion(adc, adc->scan.channels) < 0)153 dev_err(&adc->spi->dev, "Failed to read data\n");154 155 iio_push_to_buffers_with_timestamp(indio_dev, &adc->scan,156 iio_get_time_ns(indio_dev));157 mutex_unlock(&adc->lock);158 iio_trigger_notify_done(indio_dev->trig);159 160 return IRQ_HANDLED;161}162 163static int adc084s021_buffer_preenable(struct iio_dev *indio_dev)164{165 struct adc084s021 *adc = iio_priv(indio_dev);166 int scan_index;167 int i = 0;168 169 iio_for_each_active_channel(indio_dev, scan_index) {170 const struct iio_chan_spec *channel =171 &indio_dev->channels[scan_index];172 adc->tx_buf[i++] = channel->channel << 3;173 }174 adc->spi_trans.len = 2 + (i * sizeof(__be16)); /* Trash + channels */175 176 return regulator_enable(adc->reg);177}178 179static int adc084s021_buffer_postdisable(struct iio_dev *indio_dev)180{181 struct adc084s021 *adc = iio_priv(indio_dev);182 183 adc->spi_trans.len = 4; /* Trash + single channel */184 185 return regulator_disable(adc->reg);186}187 188static const struct iio_info adc084s021_info = {189 .read_raw = adc084s021_read_raw,190};191 192static const struct iio_buffer_setup_ops adc084s021_buffer_setup_ops = {193 .preenable = adc084s021_buffer_preenable,194 .postdisable = adc084s021_buffer_postdisable,195};196 197static int adc084s021_probe(struct spi_device *spi)198{199 struct iio_dev *indio_dev;200 struct adc084s021 *adc;201 int ret;202 203 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));204 if (!indio_dev) {205 dev_err(&spi->dev, "Failed to allocate IIO device\n");206 return -ENOMEM;207 }208 209 adc = iio_priv(indio_dev);210 adc->spi = spi;211 212 /* Initiate the Industrial I/O device */213 indio_dev->name = spi_get_device_id(spi)->name;214 indio_dev->modes = INDIO_DIRECT_MODE;215 indio_dev->info = &adc084s021_info;216 indio_dev->channels = adc084s021_channels;217 indio_dev->num_channels = ARRAY_SIZE(adc084s021_channels);218 219 /* Create SPI transfer for channel reads */220 adc->spi_trans.tx_buf = adc->tx_buf;221 adc->spi_trans.rx_buf = adc->rx_buf;222 adc->spi_trans.len = 4; /* Trash + single channel */223 spi_message_init_with_transfers(&adc->message, &adc->spi_trans, 1);224 225 adc->reg = devm_regulator_get(&spi->dev, "vref");226 if (IS_ERR(adc->reg))227 return PTR_ERR(adc->reg);228 229 mutex_init(&adc->lock);230 231 /* Setup triggered buffer with pollfunction */232 ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, NULL,233 adc084s021_buffer_trigger_handler,234 &adc084s021_buffer_setup_ops);235 if (ret) {236 dev_err(&spi->dev, "Failed to setup triggered buffer\n");237 return ret;238 }239 240 return devm_iio_device_register(&spi->dev, indio_dev);241}242 243static const struct of_device_id adc084s021_of_match[] = {244 { .compatible = "ti,adc084s021", },245 { }246};247MODULE_DEVICE_TABLE(of, adc084s021_of_match);248 249static const struct spi_device_id adc084s021_id[] = {250 { ADC084S021_DRIVER_NAME, 0 },251 { }252};253MODULE_DEVICE_TABLE(spi, adc084s021_id);254 255static struct spi_driver adc084s021_driver = {256 .driver = {257 .name = ADC084S021_DRIVER_NAME,258 .of_match_table = adc084s021_of_match,259 },260 .probe = adc084s021_probe,261 .id_table = adc084s021_id,262};263module_spi_driver(adc084s021_driver);264 265MODULE_AUTHOR("Mårten Lindahl <martenli@axis.com>");266MODULE_DESCRIPTION("Texas Instruments ADC084S021");267MODULE_LICENSE("GPL v2");268MODULE_VERSION("1.0");269