--- /dev/null
+/*
+ * 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");
Code Review / kvmfornfv.git / blobdiff