diff options
Diffstat (limited to 'kernel/drivers/iio/amplifiers/ad8366.c')
| -rw-r--r-- | kernel/drivers/iio/amplifiers/ad8366.c | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/kernel/drivers/iio/amplifiers/ad8366.c b/kernel/drivers/iio/amplifiers/ad8366.c new file mode 100644 index 000000000..c0d364eba --- /dev/null +++ b/kernel/drivers/iio/amplifiers/ad8366.c @@ -0,0 +1,213 @@ +/* + * AD8366 SPI Dual-Digital Variable Gain Amplifier (VGA) + * + * Copyright 2012 Analog Devices Inc. + * + * Licensed under the GPL-2. + */ + +#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/bitrev.h> + +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> + +struct ad8366_state { + struct spi_device *spi; + struct regulator *reg; + unsigned char ch[2]; + /* + * DMA (thus cache coherency maintenance) requires the + * transfer buffers to live in their own cache lines. + */ + unsigned char data[2] ____cacheline_aligned; +}; + +static int ad8366_write(struct iio_dev *indio_dev, + unsigned char ch_a, unsigned char ch_b) +{ + struct ad8366_state *st = iio_priv(indio_dev); + int ret; + + ch_a = bitrev8(ch_a & 0x3F); + ch_b = bitrev8(ch_b & 0x3F); + + st->data[0] = ch_b >> 4; + st->data[1] = (ch_b << 4) | (ch_a >> 2); + + ret = spi_write(st->spi, st->data, ARRAY_SIZE(st->data)); + if (ret < 0) + dev_err(&indio_dev->dev, "write failed (%d)", ret); + + return ret; +} + +static int ad8366_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, + int *val2, + long m) +{ + struct ad8366_state *st = iio_priv(indio_dev); + int ret; + unsigned code; + + mutex_lock(&indio_dev->mlock); + switch (m) { + case IIO_CHAN_INFO_HARDWAREGAIN: + code = st->ch[chan->channel]; + + /* Values in dB */ + code = code * 253 + 4500; + *val = code / 1000; + *val2 = (code % 1000) * 1000; + + ret = IIO_VAL_INT_PLUS_MICRO_DB; + break; + default: + ret = -EINVAL; + } + mutex_unlock(&indio_dev->mlock); + + return ret; +}; + +static int ad8366_write_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int val, + int val2, + long mask) +{ + struct ad8366_state *st = iio_priv(indio_dev); + unsigned code; + int ret; + + if (val < 0 || val2 < 0) + return -EINVAL; + + /* Values in dB */ + code = (((u8)val * 1000) + ((u32)val2 / 1000)); + + if (code > 20500 || code < 4500) + return -EINVAL; + + code = (code - 4500) / 253; + + mutex_lock(&indio_dev->mlock); + switch (mask) { + case IIO_CHAN_INFO_HARDWAREGAIN: + st->ch[chan->channel] = code; + ret = ad8366_write(indio_dev, st->ch[0], st->ch[1]); + break; + default: + ret = -EINVAL; + } + mutex_unlock(&indio_dev->mlock); + + return ret; +} + +static const struct iio_info ad8366_info = { + .read_raw = &ad8366_read_raw, + .write_raw = &ad8366_write_raw, + .driver_module = THIS_MODULE, +}; + +#define AD8366_CHAN(_channel) { \ + .type = IIO_VOLTAGE, \ + .output = 1, \ + .indexed = 1, \ + .channel = _channel, \ + .info_mask_separate = BIT(IIO_CHAN_INFO_HARDWAREGAIN),\ +} + +static const struct iio_chan_spec ad8366_channels[] = { + AD8366_CHAN(0), + AD8366_CHAN(1), +}; + +static int ad8366_probe(struct spi_device *spi) +{ + struct iio_dev *indio_dev; + struct ad8366_state *st; + int ret; + + indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); + if (indio_dev == NULL) + return -ENOMEM; + + st = iio_priv(indio_dev); + + st->reg = devm_regulator_get(&spi->dev, "vcc"); + if (!IS_ERR(st->reg)) { + ret = regulator_enable(st->reg); + if (ret) + return ret; + } + + spi_set_drvdata(spi, indio_dev); + st->spi = spi; + + indio_dev->dev.parent = &spi->dev; + indio_dev->name = spi_get_device_id(spi)->name; + indio_dev->info = &ad8366_info; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->channels = ad8366_channels; + indio_dev->num_channels = ARRAY_SIZE(ad8366_channels); + + ret = iio_device_register(indio_dev); + if (ret) + goto error_disable_reg; + + ad8366_write(indio_dev, 0, 0); + + return 0; + +error_disable_reg: + if (!IS_ERR(st->reg)) + regulator_disable(st->reg); + + return ret; +} + +static int ad8366_remove(struct spi_device *spi) +{ + struct iio_dev *indio_dev = spi_get_drvdata(spi); + struct ad8366_state *st = iio_priv(indio_dev); + struct regulator *reg = st->reg; + + iio_device_unregister(indio_dev); + + if (!IS_ERR(reg)) + regulator_disable(reg); + + return 0; +} + +static const struct spi_device_id ad8366_id[] = { + {"ad8366", 0}, + {} +}; + +static struct spi_driver ad8366_driver = { + .driver = { + .name = KBUILD_MODNAME, + .owner = THIS_MODULE, + }, + .probe = ad8366_probe, + .remove = ad8366_remove, + .id_table = ad8366_id, +}; + +module_spi_driver(ad8366_driver); + +MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>"); +MODULE_DESCRIPTION("Analog Devices AD8366 VGA"); +MODULE_LICENSE("GPL v2"); |