diff options
Diffstat (limited to 'drivers/iio/adc/ti-adc128s052.c')
| -rw-r--r-- | drivers/iio/adc/ti-adc128s052.c | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/drivers/iio/adc/ti-adc128s052.c b/drivers/iio/adc/ti-adc128s052.c new file mode 100644 index 000000000..655cb564e --- /dev/null +++ b/drivers/iio/adc/ti-adc128s052.c @@ -0,0 +1,179 @@ +/* + * Copyright (C) 2014 Angelo Compagnucci <angelo.compagnucci@gmail.com> + * + * Driver for Texas Instruments' ADC128S052 ADC chip. + * Datasheet can be found here: + * http://www.ti.com/lit/ds/symlink/adc128s052.pdf + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/err.h> +#include <linux/spi/spi.h> +#include <linux/module.h> +#include <linux/iio/iio.h> +#include <linux/regulator/consumer.h> + +struct adc128 { + struct spi_device *spi; + + struct regulator *reg; + struct mutex lock; + + u8 buffer[2] ____cacheline_aligned; +}; + +static int adc128_adc_conversion(struct adc128 *adc, u8 channel) +{ + int ret; + + mutex_lock(&adc->lock); + + adc->buffer[0] = channel << 3; + adc->buffer[1] = 0; + + ret = spi_write(adc->spi, &adc->buffer, 2); + if (ret < 0) { + mutex_unlock(&adc->lock); + return ret; + } + + ret = spi_read(adc->spi, &adc->buffer, 2); + + mutex_unlock(&adc->lock); + + if (ret < 0) + return ret; + + return ((adc->buffer[0] << 8 | adc->buffer[1]) & 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: + + ret = regulator_get_voltage(adc->reg); + if (ret < 0) + return ret; + + *val = ret / 1000; + *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 adc128_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_info adc128_info = { + .read_raw = adc128_read_raw, + .driver_module = THIS_MODULE, +}; + +static int adc128_probe(struct spi_device *spi) +{ + 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; + + spi_set_drvdata(spi, indio_dev); + + indio_dev->dev.parent = &spi->dev; + indio_dev->name = spi_get_device_id(spi)->name; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->info = &adc128_info; + + indio_dev->channels = adc128_channels; + indio_dev->num_channels = ARRAY_SIZE(adc128_channels); + + adc->reg = devm_regulator_get(&spi->dev, "vref"); + if (IS_ERR(adc->reg)) + return PTR_ERR(adc->reg); + + ret = regulator_enable(adc->reg); + if (ret < 0) + return ret; + + mutex_init(&adc->lock); + + ret = iio_device_register(indio_dev); + + return ret; +} + +static int adc128_remove(struct spi_device *spi) +{ + struct iio_dev *indio_dev = spi_get_drvdata(spi); + struct adc128 *adc = iio_priv(indio_dev); + + iio_device_unregister(indio_dev); + regulator_disable(adc->reg); + + return 0; +} + +static const struct spi_device_id adc128_id[] = { + { "adc128s052", 0}, + { } +}; +MODULE_DEVICE_TABLE(spi, adc128_id); + +static struct spi_driver adc128_driver = { + .driver = { + .name = "adc128s052", + .owner = THIS_MODULE, + }, + .probe = adc128_probe, + .remove = adc128_remove, + .id_table = adc128_id, +}; +module_spi_driver(adc128_driver); + +MODULE_AUTHOR("Angelo Compagnucci <angelo.compagnucci@gmail.com>"); +MODULE_DESCRIPTION("Texas Instruments ADC128S052"); +MODULE_LICENSE("GPL v2"); |