| /* |
| * 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"); |