Quelle  ti-adc128s052.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2014 Angelo Compagnucci <angelo.compagnucci@gmail.com>
 *
 * Driver for Texas Instruments' ADC128S052, ADC122S021 and ADC124S021 ADC chip.
 * Datasheets can be found here:
 * https://www.ti.com/lit/ds/symlink/adc128s052.pdf
 * https://www.ti.com/lit/ds/symlink/adc122s021.pdf
 * https://www.ti.com/lit/ds/symlink/adc124s021.pdf
 */

#include <linux/cleanup.h>
#include <linux/err.h>
#include <linux/iio/iio.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/property.h>
#include <linux/regulator/consumer.h>
#include <linux/spi/spi.h>

struct adc128_configuration {
 const struct iio_chan_spec *channels;
 u8    num_channels;
 const char   *refname;
 int    num_other_regulators;
 const char * const  (*other_regulators)[];
};

struct adc128 {
 struct spi_device *spi;

 /*
 * Serialize the SPI 'write-channel + read data' accesses and protect
 * the shared buffer.
 */
 struct mutex lock;
 int vref_mv;
 union {
  __be16 buffer16;
  u8 buffer[2];
 } __aligned(IIO_DMA_MINALIGN);
};

static int adc128_adc_conversion(struct adc128 *adc, u8 channel)
{
 int ret;

 guard(mutex)(&adc->lock);

 adc->buffer[0] = channel << 3;
 adc->buffer[1] = 0;

 ret = spi_write(adc->spi, &adc->buffer, sizeof(adc->buffer));
 if (ret < 0)
  return ret;

 ret = spi_read(adc->spi, &adc->buffer16, sizeof(adc->buffer16));
 if (ret < 0)
  return ret;

 return be16_to_cpu(adc->buffer16) & 0xFFF;
}

static int adc128_read_raw(struct iio_dev *indio_dev,
      struct iio_chan_spec const *channel, int *val,
      int *val2, long mask)
{
 struct adc128 *adc = iio_priv(indio_dev);
 int ret;

 switch (mask) {
 case IIO_CHAN_INFO_RAW:

  ret = adc128_adc_conversion(adc, channel->channel);
  if (ret < 0)
   return ret;

  *val = ret;
  return IIO_VAL_INT;

 case IIO_CHAN_INFO_SCALE:

  *val = adc->vref_mv;
  *val2 = 12;
  return IIO_VAL_FRACTIONAL_LOG2;

 default:
  return -EINVAL;
 }

}

#define ADC128_VOLTAGE_CHANNEL(num) \
 { \
  .type = IIO_VOLTAGE, \
  .indexed = 1, \
  .channel = (num), \
  .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
  .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
 }

static const struct iio_chan_spec adc128s052_channels[] = {
 ADC128_VOLTAGE_CHANNEL(0),
 ADC128_VOLTAGE_CHANNEL(1),
 ADC128_VOLTAGE_CHANNEL(2),
 ADC128_VOLTAGE_CHANNEL(3),
 ADC128_VOLTAGE_CHANNEL(4),
 ADC128_VOLTAGE_CHANNEL(5),
 ADC128_VOLTAGE_CHANNEL(6),
 ADC128_VOLTAGE_CHANNEL(7),
};

static const struct iio_chan_spec adc122s021_channels[] = {
 ADC128_VOLTAGE_CHANNEL(0),
 ADC128_VOLTAGE_CHANNEL(1),
};

static const struct iio_chan_spec adc124s021_channels[] = {
 ADC128_VOLTAGE_CHANNEL(0),
 ADC128_VOLTAGE_CHANNEL(1),
 ADC128_VOLTAGE_CHANNEL(2),
 ADC128_VOLTAGE_CHANNEL(3),
};

static const char * const bd79104_regulators[] = { "iovdd" };

static const struct adc128_configuration adc128_config[] = {
 {
  .channels = adc128s052_channels,
  .num_channels = ARRAY_SIZE(adc128s052_channels),
  .refname = "vref",
 }, {
  .channels = adc122s021_channels,
  .num_channels = ARRAY_SIZE(adc122s021_channels),
  .refname = "vref",
 }, {
  .channels = adc124s021_channels,
  .num_channels = ARRAY_SIZE(adc124s021_channels),
  .refname = "vref",
 }, {
  .channels = adc128s052_channels,
  .num_channels = ARRAY_SIZE(adc128s052_channels),
  .refname = "vdd",
  .other_regulators = &bd79104_regulators,
  .num_other_regulators = 1,
 },
};

static const struct iio_info adc128_info = {
 .read_raw = adc128_read_raw,
};

static int adc128_probe(struct spi_device *spi)
{
 const struct adc128_configuration *config;
 struct iio_dev *indio_dev;
 struct adc128 *adc;
 int ret;

 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
 if (!indio_dev)
  return -ENOMEM;

 adc = iio_priv(indio_dev);
 adc->spi = spi;

 indio_dev->name = spi_get_device_id(spi)->name;
 indio_dev->modes = INDIO_DIRECT_MODE;
 indio_dev->info = &adc128_info;

 config = spi_get_device_match_data(spi);

 indio_dev->channels = config->channels;
 indio_dev->num_channels = config->num_channels;

 ret = devm_regulator_get_enable_read_voltage(&spi->dev,
           config->refname);
 if (ret < 0)
  return dev_err_probe(&spi->dev, ret,
         "failed to read '%s' voltage",
         config->refname);

 adc->vref_mv = ret / 1000;

 if (config->num_other_regulators) {
  ret = devm_regulator_bulk_get_enable(&spi->dev,
      config->num_other_regulators,
      *config->other_regulators);
  if (ret)
   return dev_err_probe(&spi->dev, ret,
          "Failed to enable regulators\n");
 }

 ret = devm_mutex_init(&spi->dev, &adc->lock);
 if (ret)
  return ret;

 return devm_iio_device_register(&spi->dev, indio_dev);
}

static const struct of_device_id adc128_of_match[] = {
 { .compatible = "ti,adc128s052", .data = &adc128_config[0] },
 { .compatible = "ti,adc122s021", .data = &adc128_config[1] },
 { .compatible = "ti,adc122s051", .data = &adc128_config[1] },
 { .compatible = "ti,adc122s101", .data = &adc128_config[1] },
 { .compatible = "ti,adc124s021", .data = &adc128_config[2] },
 { .compatible = "ti,adc124s051", .data = &adc128_config[2] },
 { .compatible = "ti,adc124s101", .data = &adc128_config[2] },
 { .compatible = "rohm,bd79104", .data = &adc128_config[3] },
 { }
};
MODULE_DEVICE_TABLE(of, adc128_of_match);

static const struct spi_device_id adc128_id[] = {
 { "adc128s052", (kernel_ulong_t)&adc128_config[0] },
 { "adc122s021", (kernel_ulong_t)&adc128_config[1] },
 { "adc122s051", (kernel_ulong_t)&adc128_config[1] },
 { "adc122s101", (kernel_ulong_t)&adc128_config[1] },
 { "adc124s021", (kernel_ulong_t)&adc128_config[2] },
 { "adc124s051", (kernel_ulong_t)&adc128_config[2] },
 { "adc124s101", (kernel_ulong_t)&adc128_config[2] },
 { "bd79104", (kernel_ulong_t)&adc128_config[3] },
 { }
};
MODULE_DEVICE_TABLE(spi, adc128_id);

static const struct acpi_device_id adc128_acpi_match[] = {
 { "AANT1280", (kernel_ulong_t)&adc128_config[2] },
 { }
};
MODULE_DEVICE_TABLE(acpi, adc128_acpi_match);

static struct spi_driver adc128_driver = {
 .driver = {
  .name = "adc128s052",
  .of_match_table = adc128_of_match,
  .acpi_match_table = adc128_acpi_match,
 },
 .probe = adc128_probe,
 .id_table = adc128_id,
};
module_spi_driver(adc128_driver);

MODULE_AUTHOR("Angelo Compagnucci ");
MODULE_DESCRIPTION("Texas Instruments ADC128S052");
MODULE_LICENSE("GPL v2");