diff options
Diffstat (limited to 'drivers/iio/adc/ad7476.c')
| -rw-r--r-- | drivers/iio/adc/ad7476.c | 315 |
1 files changed, 315 insertions, 0 deletions
diff --git a/drivers/iio/adc/ad7476.c b/drivers/iio/adc/ad7476.c new file mode 100644 index 000000000..ce400ec17 --- /dev/null +++ b/drivers/iio/adc/ad7476.c @@ -0,0 +1,315 @@ +/* + * AD7466/7/8 AD7476/5/7/8 (A) SPI ADC driver + * + * Copyright 2010 Analog Devices Inc. + * + * Licensed under the GPL-2 or later. + */ + +#include <linux/device.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/sysfs.h> +#include <linux/spi/spi.h> +#include <linux/regulator/consumer.h> +#include <linux/err.h> +#include <linux/module.h> +#include <linux/bitops.h> + +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> +#include <linux/iio/buffer.h> +#include <linux/iio/trigger_consumer.h> +#include <linux/iio/triggered_buffer.h> + +struct ad7476_state; + +struct ad7476_chip_info { + unsigned int int_vref_uv; + struct iio_chan_spec channel[2]; + void (*reset)(struct ad7476_state *); +}; + +struct ad7476_state { + struct spi_device *spi; + const struct ad7476_chip_info *chip_info; + struct regulator *reg; + struct spi_transfer xfer; + struct spi_message msg; + /* + * DMA (thus cache coherency maintenance) requires the + * transfer buffers to live in their own cache lines. + * Make the buffer large enough for one 16 bit sample and one 64 bit + * aligned 64 bit timestamp. + */ + unsigned char data[ALIGN(2, sizeof(s64)) + sizeof(s64)] + ____cacheline_aligned; +}; + +enum ad7476_supported_device_ids { + ID_AD7091R, + ID_AD7276, + ID_AD7277, + ID_AD7278, + ID_AD7466, + ID_AD7467, + ID_AD7468, + ID_AD7495, + ID_AD7940, +}; + +static irqreturn_t ad7476_trigger_handler(int irq, void *p) +{ + struct iio_poll_func *pf = p; + struct iio_dev *indio_dev = pf->indio_dev; + struct ad7476_state *st = iio_priv(indio_dev); + int b_sent; + + b_sent = spi_sync(st->spi, &st->msg); + if (b_sent < 0) + goto done; + + iio_push_to_buffers_with_timestamp(indio_dev, st->data, + iio_get_time_ns()); +done: + iio_trigger_notify_done(indio_dev->trig); + + return IRQ_HANDLED; +} + +static void ad7091_reset(struct ad7476_state *st) +{ + /* Any transfers with 8 scl cycles will reset the device */ + spi_read(st->spi, st->data, 1); +} + +static int ad7476_scan_direct(struct ad7476_state *st) +{ + int ret; + + ret = spi_sync(st->spi, &st->msg); + if (ret) + return ret; + + return be16_to_cpup((__be16 *)st->data); +} + +static int ad7476_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, + int *val2, + long m) +{ + int ret; + struct ad7476_state *st = iio_priv(indio_dev); + int scale_uv; + + switch (m) { + case IIO_CHAN_INFO_RAW: + mutex_lock(&indio_dev->mlock); + if (iio_buffer_enabled(indio_dev)) + ret = -EBUSY; + else + ret = ad7476_scan_direct(st); + mutex_unlock(&indio_dev->mlock); + + if (ret < 0) + return ret; + *val = (ret >> st->chip_info->channel[0].scan_type.shift) & + GENMASK(st->chip_info->channel[0].scan_type.realbits - 1, 0); + return IIO_VAL_INT; + case IIO_CHAN_INFO_SCALE: + if (!st->chip_info->int_vref_uv) { + scale_uv = regulator_get_voltage(st->reg); + if (scale_uv < 0) + return scale_uv; + } else { + scale_uv = st->chip_info->int_vref_uv; + } + *val = scale_uv / 1000; + *val2 = chan->scan_type.realbits; + return IIO_VAL_FRACTIONAL_LOG2; + } + return -EINVAL; +} + +#define _AD7476_CHAN(bits, _shift, _info_mask_sep) \ + { \ + .type = IIO_VOLTAGE, \ + .indexed = 1, \ + .info_mask_separate = _info_mask_sep, \ + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ + .scan_type = { \ + .sign = 'u', \ + .realbits = (bits), \ + .storagebits = 16, \ + .shift = (_shift), \ + .endianness = IIO_BE, \ + }, \ +} + +#define AD7476_CHAN(bits) _AD7476_CHAN((bits), 13 - (bits), \ + BIT(IIO_CHAN_INFO_RAW)) +#define AD7940_CHAN(bits) _AD7476_CHAN((bits), 15 - (bits), \ + BIT(IIO_CHAN_INFO_RAW)) +#define AD7091R_CHAN(bits) _AD7476_CHAN((bits), 16 - (bits), 0) + +static const struct ad7476_chip_info ad7476_chip_info_tbl[] = { + [ID_AD7091R] = { + .channel[0] = AD7091R_CHAN(12), + .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1), + .reset = ad7091_reset, + }, + [ID_AD7276] = { + .channel[0] = AD7940_CHAN(12), + .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1), + }, + [ID_AD7277] = { + .channel[0] = AD7940_CHAN(10), + .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1), + }, + [ID_AD7278] = { + .channel[0] = AD7940_CHAN(8), + .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1), + }, + [ID_AD7466] = { + .channel[0] = AD7476_CHAN(12), + .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1), + }, + [ID_AD7467] = { + .channel[0] = AD7476_CHAN(10), + .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1), + }, + [ID_AD7468] = { + .channel[0] = AD7476_CHAN(8), + .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1), + }, + [ID_AD7495] = { + .channel[0] = AD7476_CHAN(12), + .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1), + .int_vref_uv = 2500000, + }, + [ID_AD7940] = { + .channel[0] = AD7940_CHAN(14), + .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1), + }, +}; + +static const struct iio_info ad7476_info = { + .driver_module = THIS_MODULE, + .read_raw = &ad7476_read_raw, +}; + +static int ad7476_probe(struct spi_device *spi) +{ + struct ad7476_state *st; + struct iio_dev *indio_dev; + int ret; + + indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); + if (!indio_dev) + return -ENOMEM; + + st = iio_priv(indio_dev); + st->chip_info = + &ad7476_chip_info_tbl[spi_get_device_id(spi)->driver_data]; + + st->reg = devm_regulator_get(&spi->dev, "vcc"); + if (IS_ERR(st->reg)) + return PTR_ERR(st->reg); + + ret = regulator_enable(st->reg); + if (ret) + return ret; + + spi_set_drvdata(spi, indio_dev); + + st->spi = spi; + + /* Establish that the iio_dev is a child of the spi device */ + indio_dev->dev.parent = &spi->dev; + indio_dev->name = spi_get_device_id(spi)->name; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->channels = st->chip_info->channel; + indio_dev->num_channels = 2; + indio_dev->info = &ad7476_info; + /* Setup default message */ + + st->xfer.rx_buf = &st->data; + st->xfer.len = st->chip_info->channel[0].scan_type.storagebits / 8; + + spi_message_init(&st->msg); + spi_message_add_tail(&st->xfer, &st->msg); + + ret = iio_triggered_buffer_setup(indio_dev, NULL, + &ad7476_trigger_handler, NULL); + if (ret) + goto error_disable_reg; + + if (st->chip_info->reset) + st->chip_info->reset(st); + + ret = iio_device_register(indio_dev); + if (ret) + goto error_ring_unregister; + return 0; + +error_ring_unregister: + iio_triggered_buffer_cleanup(indio_dev); +error_disable_reg: + regulator_disable(st->reg); + + return ret; +} + +static int ad7476_remove(struct spi_device *spi) +{ + struct iio_dev *indio_dev = spi_get_drvdata(spi); + struct ad7476_state *st = iio_priv(indio_dev); + + iio_device_unregister(indio_dev); + iio_triggered_buffer_cleanup(indio_dev); + regulator_disable(st->reg); + + return 0; +} + +static const struct spi_device_id ad7476_id[] = { + {"ad7091r", ID_AD7091R}, + {"ad7273", ID_AD7277}, + {"ad7274", ID_AD7276}, + {"ad7276", ID_AD7276}, + {"ad7277", ID_AD7277}, + {"ad7278", ID_AD7278}, + {"ad7466", ID_AD7466}, + {"ad7467", ID_AD7467}, + {"ad7468", ID_AD7468}, + {"ad7475", ID_AD7466}, + {"ad7476", ID_AD7466}, + {"ad7476a", ID_AD7466}, + {"ad7477", ID_AD7467}, + {"ad7477a", ID_AD7467}, + {"ad7478", ID_AD7468}, + {"ad7478a", ID_AD7468}, + {"ad7495", ID_AD7495}, + {"ad7910", ID_AD7467}, + {"ad7920", ID_AD7466}, + {"ad7940", ID_AD7940}, + {} +}; +MODULE_DEVICE_TABLE(spi, ad7476_id); + +static struct spi_driver ad7476_driver = { + .driver = { + .name = "ad7476", + .owner = THIS_MODULE, + }, + .probe = ad7476_probe, + .remove = ad7476_remove, + .id_table = ad7476_id, +}; +module_spi_driver(ad7476_driver); + +MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>"); +MODULE_DESCRIPTION("Analog Devices AD7476 and similar 1-channel ADCs"); +MODULE_LICENSE("GPL v2"); |