1 files changed, 120 insertions, 0 deletions

diff --git a/kernel/drivers/staging/iio/resolver/ad2s90.c b/kernel/drivers/staging/iio/resolver/ad2s90.c
new file mode 100644
index 000000000..e24c58906
--- /dev/null
+++ b/kernel/drivers/staging/iio/resolver/ad2s90.c
@@ -0,0 +1,120 @@
+/*
+ * ad2s90.c simple support for the ADI Resolver to Digital Converters: AD2S90
+ *
+ * Copyright (c) 2010-2010 Analog Devices Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+#include <linux/types.h>
+#include <linux/mutex.h>
+#include <linux/device.h>
+#include <linux/spi/spi.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/module.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+struct ad2s90_state {
+	struct mutex lock;
+	struct spi_device *sdev;
+	u8 rx[2] ____cacheline_aligned;
+};
+
+static int ad2s90_read_raw(struct iio_dev *indio_dev,
+			   struct iio_chan_spec const *chan,
+			   int *val,
+			   int *val2,
+			   long m)
+{
+	int ret;
+	struct ad2s90_state *st = iio_priv(indio_dev);
+
+	mutex_lock(&st->lock);
+	ret = spi_read(st->sdev, st->rx, 2);
+	if (ret)
+		goto error_ret;
+	*val = (((u16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
+
+error_ret:
+	mutex_unlock(&st->lock);
+
+	return IIO_VAL_INT;
+}
+
+static const struct iio_info ad2s90_info = {
+	.read_raw = &ad2s90_read_raw,
+	.driver_module = THIS_MODULE,
+};
+
+static const struct iio_chan_spec ad2s90_chan = {
+	.type = IIO_ANGL,
+	.indexed = 1,
+	.channel = 0,
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+};
+
+static int ad2s90_probe(struct spi_device *spi)
+{
+	struct iio_dev *indio_dev;
+	struct ad2s90_state *st;
+	int ret = 0;
+
+	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
+	if (!indio_dev)
+		return -ENOMEM;
+	st = iio_priv(indio_dev);
+	spi_set_drvdata(spi, indio_dev);
+
+	mutex_init(&st->lock);
+	st->sdev = spi;
+	indio_dev->dev.parent = &spi->dev;
+	indio_dev->info = &ad2s90_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = &ad2s90_chan;
+	indio_dev->num_channels = 1;
+	indio_dev->name = spi_get_device_id(spi)->name;
+
+	ret = iio_device_register(indio_dev);
+	if (ret)
+		return ret;
+
+	/* need 600ns between CS and the first falling edge of SCLK */
+	spi->max_speed_hz = 830000;
+	spi->mode = SPI_MODE_3;
+	spi_setup(spi);
+
+	return 0;
+}
+
+static int ad2s90_remove(struct spi_device *spi)
+{
+	iio_device_unregister(spi_get_drvdata(spi));
+
+	return 0;
+}
+
+static const struct spi_device_id ad2s90_id[] = {
+	{ "ad2s90" },
+	{}
+};
+MODULE_DEVICE_TABLE(spi, ad2s90_id);
+
+static struct spi_driver ad2s90_driver = {
+	.driver = {
+		.name = "ad2s90",
+		.owner = THIS_MODULE,
+	},
+	.probe = ad2s90_probe,
+	.remove = ad2s90_remove,
+	.id_table = ad2s90_id,
+};
+module_spi_driver(ad2s90_driver);
+
+MODULE_AUTHOR("Graff Yang <graff.yang@gmail.com>");
+MODULE_DESCRIPTION("Analog Devices AD2S90 Resolver to Digital SPI driver");
+MODULE_LICENSE("GPL v2");