diff options
Diffstat (limited to 'drivers/staging/iio/resolver/ad2s1200.c')
| -rw-r--r-- | drivers/staging/iio/resolver/ad2s1200.c | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/drivers/staging/iio/resolver/ad2s1200.c b/drivers/staging/iio/resolver/ad2s1200.c new file mode 100644 index 000000000..c17893b49 --- /dev/null +++ b/drivers/staging/iio/resolver/ad2s1200.c @@ -0,0 +1,167 @@ +/* + * ad2s1200.c simple support for the ADI Resolver to Digital Converters: + * AD2S1200/1205 + * + * 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/delay.h> +#include <linux/gpio.h> +#include <linux/module.h> +#include <linux/bitops.h> + +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> + +#define DRV_NAME "ad2s1200" + +/* input pin sample and rdvel is controlled by driver */ +#define AD2S1200_PN 2 + +/* input clock on serial interface */ +#define AD2S1200_HZ 8192000 +/* clock period in nano second */ +#define AD2S1200_TSCLK (1000000000/AD2S1200_HZ) + +struct ad2s1200_state { + struct mutex lock; + struct spi_device *sdev; + int sample; + int rdvel; + u8 rx[2] ____cacheline_aligned; +}; + +static int ad2s1200_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, + int *val2, + long m) +{ + int ret = 0; + s16 vel; + struct ad2s1200_state *st = iio_priv(indio_dev); + + mutex_lock(&st->lock); + gpio_set_value(st->sample, 0); + /* delay (6 * AD2S1200_TSCLK + 20) nano seconds */ + udelay(1); + gpio_set_value(st->sample, 1); + gpio_set_value(st->rdvel, !!(chan->type == IIO_ANGL)); + ret = spi_read(st->sdev, st->rx, 2); + if (ret < 0) { + mutex_unlock(&st->lock); + return ret; + } + + switch (chan->type) { + case IIO_ANGL: + *val = (((u16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4); + break; + case IIO_ANGL_VEL: + vel = (((s16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4); + vel = sign_extend32(vel, 11); + *val = vel; + break; + default: + mutex_unlock(&st->lock); + return -EINVAL; + } + /* delay (2 * AD2S1200_TSCLK + 20) ns for sample pulse */ + udelay(1); + mutex_unlock(&st->lock); + return IIO_VAL_INT; +} + +static const struct iio_chan_spec ad2s1200_channels[] = { + { + .type = IIO_ANGL, + .indexed = 1, + .channel = 0, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), + }, { + .type = IIO_ANGL_VEL, + .indexed = 1, + .channel = 0, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), + } +}; + +static const struct iio_info ad2s1200_info = { + .read_raw = &ad2s1200_read_raw, + .driver_module = THIS_MODULE, +}; + +static int ad2s1200_probe(struct spi_device *spi) +{ + struct ad2s1200_state *st; + struct iio_dev *indio_dev; + int pn, ret = 0; + unsigned short *pins = spi->dev.platform_data; + + for (pn = 0; pn < AD2S1200_PN; pn++) { + ret = devm_gpio_request_one(&spi->dev, pins[pn], GPIOF_DIR_OUT, + DRV_NAME); + if (ret) { + dev_err(&spi->dev, "request gpio pin %d failed\n", + pins[pn]); + return ret; + } + } + indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); + if (!indio_dev) + return -ENOMEM; + spi_set_drvdata(spi, indio_dev); + st = iio_priv(indio_dev); + mutex_init(&st->lock); + st->sdev = spi; + st->sample = pins[0]; + st->rdvel = pins[1]; + + indio_dev->dev.parent = &spi->dev; + indio_dev->info = &ad2s1200_info; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->channels = ad2s1200_channels; + indio_dev->num_channels = ARRAY_SIZE(ad2s1200_channels); + indio_dev->name = spi_get_device_id(spi)->name; + + ret = devm_iio_device_register(&spi->dev, indio_dev); + if (ret) + return ret; + + spi->max_speed_hz = AD2S1200_HZ; + spi->mode = SPI_MODE_3; + spi_setup(spi); + + return 0; +} + +static const struct spi_device_id ad2s1200_id[] = { + { "ad2s1200" }, + { "ad2s1205" }, + {} +}; +MODULE_DEVICE_TABLE(spi, ad2s1200_id); + +static struct spi_driver ad2s1200_driver = { + .driver = { + .name = DRV_NAME, + .owner = THIS_MODULE, + }, + .probe = ad2s1200_probe, + .id_table = ad2s1200_id, +}; +module_spi_driver(ad2s1200_driver); + +MODULE_AUTHOR("Graff Yang <graff.yang@gmail.com>"); +MODULE_DESCRIPTION("Analog Devices AD2S1200/1205 Resolver to Digital SPI driver"); +MODULE_LICENSE("GPL v2"); |