/drivers/staging/iio/resolver/ad2s90.c
https://bitbucket.org/slukk/jb-tsm-kernel-4.2 · C · 161 lines · 122 code · 28 blank · 11 comment · 6 complexity · a4c5d420f8706db6eb5715c6569d251d MD5 · raw file
- /*
- * 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 const struct iio_info ad2s90_info = {
- .attrs = &ad2s90_attribute_group,
- .driver_module = THIS_MODULE,
- };
- 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(0);
- if (st->idev == NULL) {
- ret = -ENOMEM;
- goto error_free_st;
- }
- st->idev->dev.parent = &spi->dev;
- st->idev->info = &ad2s90_info;
- st->idev->dev_data = (void *)(st);
- 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");