iio: amplifiers: New driver for AD8366 Dual-Digital Variable Gain Amplifier (e71d42e0) · Commits · e / devices / android_kernel_fairphone_FP5

drivers/iio/Kconfig

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		@@ -48,4 +48,6 @@ config IIO_CONSUMERS_PER_TRIGGER
		This value controls the maximum number of consumers that a
		given trigger may handle. Default is 2.

		source "drivers/iio/amplifiers/Kconfig"

		endif # IIO

drivers/iio/Makefile

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		@@ -8,3 +8,5 @@ industrialio-$(CONFIG_IIO_BUFFER) += industrialio-buffer.o
		industrialio-$(CONFIG_IIO_TRIGGER) += industrialio-trigger.o

		obj-$(CONFIG_IIO_KFIFO_BUF) += kfifo_buf.o

		obj-y += amplifiers/

drivers/iio/amplifiers/Kconfig

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		#
		# Gain Amplifiers, etc.
		#
		menu "Amplifiers"

		config AD8366
		tristate "Analog Devices AD8366 VGA"
		depends on SPI
		select BITREVERSE
		help
		Say yes here to build support for Analog Devices AD8366
		SPI Dual-Digital Variable Gain Amplifier (VGA).

		To compile this driver as a module, choose M here: the
		module will be called ad8366.

		endmenu

drivers/iio/amplifiers/Makefile

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		#
		# Makefile iio/amplifiers
		#

		obj-$(CONFIG_AD8366) += ad8366.o

drivers/iio/amplifiers/ad8366.c

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		/*
		* 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, char unsigned 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 = IIO_CHAN_INFO_HARDWAREGAIN_SEPARATE_BIT,\
		}

		static const struct iio_chan_spec ad8366_channels[] = {
		AD8366_CHAN(0),
		AD8366_CHAN(1),
		};

		static int __devinit ad8366_probe(struct spi_device *spi)
		{
		struct iio_dev *indio_dev;
		struct ad8366_state *st;
		int ret;

		indio_dev = iio_device_alloc(sizeof(*st));
		if (indio_dev == NULL)
		return -ENOMEM;

		st = iio_priv(indio_dev);

		st->reg = regulator_get(&spi->dev, "vcc");
		if (!IS_ERR(st->reg)) {
		ret = regulator_enable(st->reg);
		if (ret)
		goto error_put_reg;
		}

		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);
		error_put_reg:
		if (!IS_ERR(st->reg))
		regulator_put(st->reg);

		iio_device_free(indio_dev);

		return ret;
		}

		static int __devexit 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);
		regulator_put(reg);
		}

		iio_device_free(indio_dev);

		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 = __devexit_p(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");