staging: iio: resolver: new driver for AD2S90 devices (f46d9f15) · Commits · e / devices / android_kernel_teracube_2e

drivers/staging/iio/Kconfig

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		@@ -50,6 +50,7 @@ source "drivers/staging/iio/imu/Kconfig"
		source "drivers/staging/iio/light/Kconfig"
		source "drivers/staging/iio/magnetometer/Kconfig"
		source "drivers/staging/iio/meter/Kconfig"
		source "drivers/staging/iio/resolver/Kconfig"
		source "drivers/staging/iio/trigger/Kconfig"

		endif # IIO

drivers/staging/iio/Makefile

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		@@ -19,4 +19,5 @@ obj-y += imu/
		obj-y += light/
		obj-y += magnetometer/
		obj-y += meter/
		obj-y += resolver/
		obj-y += trigger/

drivers/staging/iio/resolver/Kconfig

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		#
		# Resolver/Synchro drivers
		#
		comment "Resolver to digital converters"

		config AD2S90
		tristate "Analog Devices ad2s90 driver"
		depends on SPI
		help
		Say yes here to build support for Analog Devices spi resolver
		to digital converters, ad2s90, provides direct access via sysfs.

drivers/staging/iio/resolver/Makefile

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		#
		# Makefile for Resolver/Synchro drivers
		#

		obj-$(CONFIG_AD2S90) += ad2s90.o

drivers/staging/iio/resolver/ad2s90.c

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		/*
		* 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 "../iio.h"
		#include "../sysfs.h"

		#define DRV_NAME "ad2s90"

		struct ad2s90_state {
		struct mutex lock;
		struct iio_dev *idev;
		struct spi_device *sdev;
		u8 rx[2];
		u8 tx[2];
		};

		static ssize_t ad2s90_show_angular(struct device *dev,
		struct device_attribute attr, char buf)
		{
		struct spi_message msg;
		struct spi_transfer xfer;
		int ret;
		ssize_t len = 0;
		u16 val;
		struct iio_dev *idev = dev_get_drvdata(dev);
		struct ad2s90_state *st = idev->dev_data;

		xfer.len = 1;
		xfer.tx_buf = st->tx;
		xfer.rx_buf = st->rx;
		mutex_lock(&st->lock);

		spi_message_init(&msg);
		spi_message_add_tail(&xfer, &msg);
		ret = spi_sync(st->sdev, &msg);
		if (ret)
		goto error_ret;
		val = (((u16)(st->rx[0])) << 4) \| ((st->rx[1] & 0xF0) >> 4);
		len = sprintf(buf, "%d\n", val);
		error_ret:
		mutex_unlock(&st->lock);

		return ret ? ret : len;
		}

		#define IIO_DEV_ATTR_SIMPLE_RESOLVER(_show) \
		IIO_DEVICE_ATTR(angular, S_IRUGO, _show, NULL, 0)

		static IIO_CONST_ATTR(description,
		"Low Cost, Complete 12-Bit Resolver-to-Digital Converter");
		static IIO_DEV_ATTR_SIMPLE_RESOLVER(ad2s90_show_angular);

		static struct attribute *ad2s90_attributes[] = {
		&iio_const_attr_description.dev_attr.attr,
		&iio_dev_attr_angular.dev_attr.attr,
		NULL,
		};

		static const struct attribute_group ad2s90_attribute_group = {
		.name = DRV_NAME,
		.attrs = ad2s90_attributes,
		};

		static int __devinit ad2s90_probe(struct spi_device *spi)
		{
		struct ad2s90_state *st;
		int ret = 0;

		st = kzalloc(sizeof(*st), GFP_KERNEL);
		if (st == NULL) {
		ret = -ENOMEM;
		goto error_ret;
		}
		spi_set_drvdata(spi, st);

		mutex_init(&st->lock);
		st->sdev = spi;

		st->idev = iio_allocate_device();
		if (st->idev == NULL) {
		ret = -ENOMEM;
		goto error_free_st;
		}
		st->idev->dev.parent = &spi->dev;
		st->idev->num_interrupt_lines = 0;
		st->idev->event_attrs = NULL;

		st->idev->attrs = &ad2s90_attribute_group;
		st->idev->dev_data = (void *)(st);
		st->idev->driver_module = THIS_MODULE;
		st->idev->modes = INDIO_DIRECT_MODE;

		ret = iio_device_register(st->idev);
		if (ret)
		goto error_free_dev;

		/* 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;

		error_free_dev:
		iio_free_device(st->idev);
		error_free_st:
		kfree(st);
		error_ret:
		return ret;
		}

		static int __devexit ad2s90_remove(struct spi_device *spi)
		{
		struct ad2s90_state *st = spi_get_drvdata(spi);

		iio_device_unregister(st->idev);
		kfree(st);

		return 0;
		}

		static struct spi_driver ad2s90_driver = {
		.driver = {
		.name = DRV_NAME,
		.owner = THIS_MODULE,
		},
		.probe = ad2s90_probe,
		.remove = __devexit_p(ad2s90_remove),
		};

		static __init int ad2s90_spi_init(void)
		{
		return spi_register_driver(&ad2s90_driver);
		}
		module_init(ad2s90_spi_init);

		static __exit void ad2s90_spi_exit(void)
		{
		spi_unregister_driver(&ad2s90_driver);
		}
		module_exit(ad2s90_spi_exit);

		MODULE_AUTHOR("Graff Yang <graff.yang@gmail.com>");
		MODULE_DESCRIPTION("Analog Devices AD2S90 Resolver to Digital SPI driver");
		MODULE_LICENSE("GPL v2");