iio: amplifiers: New driver for AD8366 Dual-Digital Variable Gain Amplifier

Changes since V1:

Apply review feedback:
	Introduce and use IIO_CHAN_INFO_HARDWAREGAIN
	Introduce and use Use IIO_VAL_INT_PLUS_MICRO_DB

Modify out of staging include paths.
Convert to new iio core API naming.

Changes since V2:

more sanity checking in write_raw

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
index 3ab7d48d0b0aaa819ee24f6c14ef68d7ca8d757d..bb1e35c811da5acf3a711fdd0243b935e7d68533 100644 (file)
--- a/drivers/iio/Kconfig
+++ b/drivers/iio/Kconfig
@@ -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

diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile
index d5fc57d12eac3b77c67ea73089be660b9fdd5346..55524916aa56c002f0c941461e8bd9344ea9384c 100644 (file)
--- a/drivers/iio/Makefile
+++ b/drivers/iio/Makefile
@@ -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/

diff --git a/drivers/iio/amplifiers/Kconfig b/drivers/iio/amplifiers/Kconfig
new file mode 100644 (file)
index 0000000..05d707e
--- /dev/null
+++ b/drivers/iio/amplifiers/Kconfig
@@ -0,0 +1,17 @@
+#
+# 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

diff --git a/drivers/iio/amplifiers/Makefile b/drivers/iio/amplifiers/Makefile
new file mode 100644 (file)
index 0000000..a6ca366
--- /dev/null
+++ b/drivers/iio/amplifiers/Makefile
@@ -0,0 +1,5 @@
+#
+# Makefile iio/amplifiers
+#
+
+obj-$(CONFIG_AD8366) += ad8366.o

diff --git a/drivers/iio/amplifiers/ad8366.c b/drivers/iio/amplifiers/ad8366.c
new file mode 100644 (file)
index 0000000..d8281cd
--- /dev/null
+++ b/drivers/iio/amplifiers/ad8366.c
@@ -0,0 +1,222 @@
+/*
+ * 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");