/* * 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");