265 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * TI tlc4541 ADC Driver4 *5 * Copyright (C) 2017 Phil Reid6 *7 * Datasheets can be found here:8 * https://www.ti.com/lit/gpn/tlc35419 * https://www.ti.com/lit/gpn/tlc454110 *11 * The tlc4541 requires 24 clock cycles to start a transfer.12 * Conversion then takes 2.94us to complete before data is ready13 * Data is returned MSB first.14 */15 16#include <linux/delay.h>17#include <linux/device.h>18#include <linux/err.h>19#include <linux/interrupt.h>20#include <linux/iio/iio.h>21#include <linux/iio/sysfs.h>22#include <linux/iio/buffer.h>23#include <linux/iio/trigger_consumer.h>24#include <linux/iio/triggered_buffer.h>25#include <linux/kernel.h>26#include <linux/module.h>27#include <linux/mod_devicetable.h>28#include <linux/regulator/consumer.h>29#include <linux/slab.h>30#include <linux/spi/spi.h>31#include <linux/sysfs.h>32 33struct tlc4541_state {34 struct spi_device *spi;35 struct regulator *reg;36 struct spi_transfer scan_single_xfer[3];37 struct spi_message scan_single_msg;38 39 /*40 * DMA (thus cache coherency maintenance) may require the41 * transfer buffers to live in their own cache lines.42 * 2 bytes data + 6 bytes padding + 8 bytes timestamp when43 * call iio_push_to_buffers_with_timestamp.44 */45 __be16 rx_buf[8] __aligned(IIO_DMA_MINALIGN);46};47 48struct tlc4541_chip_info {49 const struct iio_chan_spec *channels;50 unsigned int num_channels;51};52 53enum tlc4541_id {54 TLC3541,55 TLC4541,56};57 58#define TLC4541_V_CHAN(bits, bitshift) { \59 .type = IIO_VOLTAGE, \60 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \61 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \62 .scan_type = { \63 .sign = 'u', \64 .realbits = (bits), \65 .storagebits = 16, \66 .shift = (bitshift), \67 .endianness = IIO_BE, \68 }, \69 }70 71#define DECLARE_TLC4541_CHANNELS(name, bits, bitshift) \72const struct iio_chan_spec name ## _channels[] = { \73 TLC4541_V_CHAN(bits, bitshift), \74 IIO_CHAN_SOFT_TIMESTAMP(1), \75}76 77static DECLARE_TLC4541_CHANNELS(tlc3541, 14, 2);78static DECLARE_TLC4541_CHANNELS(tlc4541, 16, 0);79 80static const struct tlc4541_chip_info tlc4541_chip_info[] = {81 [TLC3541] = {82 .channels = tlc3541_channels,83 .num_channels = ARRAY_SIZE(tlc3541_channels),84 },85 [TLC4541] = {86 .channels = tlc4541_channels,87 .num_channels = ARRAY_SIZE(tlc4541_channels),88 },89};90 91static irqreturn_t tlc4541_trigger_handler(int irq, void *p)92{93 struct iio_poll_func *pf = p;94 struct iio_dev *indio_dev = pf->indio_dev;95 struct tlc4541_state *st = iio_priv(indio_dev);96 int ret;97 98 ret = spi_sync(st->spi, &st->scan_single_msg);99 if (ret < 0)100 goto done;101 102 iio_push_to_buffers_with_timestamp(indio_dev, st->rx_buf,103 iio_get_time_ns(indio_dev));104 105done:106 iio_trigger_notify_done(indio_dev->trig);107 return IRQ_HANDLED;108}109 110static int tlc4541_get_range(struct tlc4541_state *st)111{112 int vref;113 114 vref = regulator_get_voltage(st->reg);115 if (vref < 0)116 return vref;117 118 vref /= 1000;119 120 return vref;121}122 123static int tlc4541_read_raw(struct iio_dev *indio_dev,124 struct iio_chan_spec const *chan,125 int *val,126 int *val2,127 long m)128{129 int ret = 0;130 struct tlc4541_state *st = iio_priv(indio_dev);131 132 switch (m) {133 case IIO_CHAN_INFO_RAW:134 ret = iio_device_claim_direct_mode(indio_dev);135 if (ret)136 return ret;137 ret = spi_sync(st->spi, &st->scan_single_msg);138 iio_device_release_direct_mode(indio_dev);139 if (ret < 0)140 return ret;141 *val = be16_to_cpu(st->rx_buf[0]);142 *val = *val >> chan->scan_type.shift;143 *val &= GENMASK(chan->scan_type.realbits - 1, 0);144 return IIO_VAL_INT;145 case IIO_CHAN_INFO_SCALE:146 ret = tlc4541_get_range(st);147 if (ret < 0)148 return ret;149 *val = ret;150 *val2 = chan->scan_type.realbits;151 return IIO_VAL_FRACTIONAL_LOG2;152 }153 return -EINVAL;154}155 156static const struct iio_info tlc4541_info = {157 .read_raw = &tlc4541_read_raw,158};159 160static int tlc4541_probe(struct spi_device *spi)161{162 struct tlc4541_state *st;163 struct iio_dev *indio_dev;164 const struct tlc4541_chip_info *info;165 int ret;166 int8_t device_init = 0;167 168 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));169 if (indio_dev == NULL)170 return -ENOMEM;171 172 st = iio_priv(indio_dev);173 174 spi_set_drvdata(spi, indio_dev);175 176 st->spi = spi;177 178 info = &tlc4541_chip_info[spi_get_device_id(spi)->driver_data];179 180 indio_dev->name = spi_get_device_id(spi)->name;181 indio_dev->modes = INDIO_DIRECT_MODE;182 indio_dev->channels = info->channels;183 indio_dev->num_channels = info->num_channels;184 indio_dev->info = &tlc4541_info;185 186 /* perform reset */187 spi_write(spi, &device_init, 1);188 189 /* Setup default message */190 st->scan_single_xfer[0].rx_buf = &st->rx_buf[0];191 st->scan_single_xfer[0].len = 3;192 st->scan_single_xfer[1].delay.value = 3;193 st->scan_single_xfer[1].delay.unit = SPI_DELAY_UNIT_NSECS;194 st->scan_single_xfer[2].rx_buf = &st->rx_buf[0];195 st->scan_single_xfer[2].len = 2;196 197 spi_message_init_with_transfers(&st->scan_single_msg,198 st->scan_single_xfer, 3);199 200 st->reg = devm_regulator_get(&spi->dev, "vref");201 if (IS_ERR(st->reg))202 return PTR_ERR(st->reg);203 204 ret = regulator_enable(st->reg);205 if (ret)206 return ret;207 208 ret = iio_triggered_buffer_setup(indio_dev, NULL,209 &tlc4541_trigger_handler, NULL);210 if (ret)211 goto error_disable_reg;212 213 ret = iio_device_register(indio_dev);214 if (ret)215 goto error_cleanup_buffer;216 217 return 0;218 219error_cleanup_buffer:220 iio_triggered_buffer_cleanup(indio_dev);221error_disable_reg:222 regulator_disable(st->reg);223 224 return ret;225}226 227static void tlc4541_remove(struct spi_device *spi)228{229 struct iio_dev *indio_dev = spi_get_drvdata(spi);230 struct tlc4541_state *st = iio_priv(indio_dev);231 232 iio_device_unregister(indio_dev);233 iio_triggered_buffer_cleanup(indio_dev);234 regulator_disable(st->reg);235}236 237static const struct of_device_id tlc4541_dt_ids[] = {238 { .compatible = "ti,tlc3541", },239 { .compatible = "ti,tlc4541", },240 { }241};242MODULE_DEVICE_TABLE(of, tlc4541_dt_ids);243 244static const struct spi_device_id tlc4541_id[] = {245 { "tlc3541", TLC3541 },246 { "tlc4541", TLC4541 },247 { }248};249MODULE_DEVICE_TABLE(spi, tlc4541_id);250 251static struct spi_driver tlc4541_driver = {252 .driver = {253 .name = "tlc4541",254 .of_match_table = tlc4541_dt_ids,255 },256 .probe = tlc4541_probe,257 .remove = tlc4541_remove,258 .id_table = tlc4541_id,259};260module_spi_driver(tlc4541_driver);261 262MODULE_AUTHOR("Phil Reid <preid@electromag.com.au>");263MODULE_DESCRIPTION("Texas Instruments TLC4541 ADC");264MODULE_LICENSE("GPL v2");265