| /* |
| * 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 = devm_iio_device_register(indio_dev->dev.parent, 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 const struct spi_device_id ad2s90_id[] = { |
| { "ad2s90" }, |
| {} |
| }; |
| MODULE_DEVICE_TABLE(spi, ad2s90_id); |
| |
| static struct spi_driver ad2s90_driver = { |
| .driver = { |
| .name = "ad2s90", |
| }, |
| .probe = ad2s90_probe, |
| .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"); |