diff options
Diffstat (limited to 'drivers/staging/iio/resolver/ad2s90.c')
| -rw-r--r-- | drivers/staging/iio/resolver/ad2s90.c | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/drivers/staging/iio/resolver/ad2s90.c b/drivers/staging/iio/resolver/ad2s90.c new file mode 100644 index 000000000000..4143535242d9 --- /dev/null +++ b/drivers/staging/iio/resolver/ad2s90.c @@ -0,0 +1,159 @@ +/* + * 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"); |