diff options
Diffstat (limited to 'drivers/iio/resolver/ad2s1200.c')
| -rw-r--r-- | drivers/iio/resolver/ad2s1200.c | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/drivers/iio/resolver/ad2s1200.c b/drivers/iio/resolver/ad2s1200.c new file mode 100644 index 0000000..28e618a --- /dev/null +++ b/drivers/iio/resolver/ad2s1200.c @@ -0,0 +1,210 @@ +/* + * ad2s1200.c simple support for the ADI Resolver to Digital Converters: + * AD2S1200/1205 + * + * Copyright (c) 2018-2018 David Veenstra <davidjulianveenstra@gmail.com> + * 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/bitops.h> +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/gpio.h> +#include <linux/gpio/consumer.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/spi/spi.h> +#include <linux/sysfs.h> +#include <linux/types.h> + +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> + +#define DRV_NAME "ad2s1200" + +/* input clock on serial interface */ +#define AD2S1200_HZ 8192000 +/* clock period in nano second */ +#define AD2S1200_TSCLK (1000000000 / AD2S1200_HZ) + +/** + * struct ad2s1200_state - driver instance specific data. + * @lock: protects both the GPIO pins and the rx buffer. + * @sdev: spi device. + * @sample: GPIO pin SAMPLE. + * @rdvel: GPIO pin RDVEL. + * @rx: buffer for spi transfers. + */ +struct ad2s1200_state { + struct mutex lock; + struct spi_device *sdev; + struct gpio_desc *sample; + struct gpio_desc *rdvel; + __be16 rx ____cacheline_aligned; +}; + +static int ad2s1200_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, + int *val2, + long m) +{ + struct ad2s1200_state *st = iio_priv(indio_dev); + int ret; + + switch (m) { + case IIO_CHAN_INFO_SCALE: + switch (chan->type) { + case IIO_ANGL: + /* 2 * Pi / (2^12 - 1) ~= 0.001534355 */ + *val = 0; + *val2 = 1534355; + return IIO_VAL_INT_PLUS_NANO; + case IIO_ANGL_VEL: + /* 2 * Pi ~= 6.283185 */ + *val = 6; + *val2 = 283185; + return IIO_VAL_INT_PLUS_MICRO; + default: + return -EINVAL; + } + break; + case IIO_CHAN_INFO_RAW: + mutex_lock(&st->lock); + gpiod_set_value(st->sample, 0); + + /* delay (6 * AD2S1200_TSCLK + 20) nano seconds */ + udelay(1); + gpiod_set_value(st->sample, 1); + gpiod_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 = be16_to_cpup(&st->rx) >> 4; + break; + case IIO_ANGL_VEL: + *val = sign_extend32(be16_to_cpup(&st->rx) >> 4, 11); + 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; + default: + break; + } + + return -EINVAL; +} + +static const struct iio_chan_spec ad2s1200_channels[] = { + { + .type = IIO_ANGL, + .indexed = 1, + .channel = 0, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), + }, { + .type = IIO_ANGL_VEL, + .indexed = 1, + .channel = 0, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), + } +}; + +static const struct iio_info ad2s1200_info = { + .read_raw = ad2s1200_read_raw, +}; + +static int ad2s1200_probe(struct spi_device *spi) +{ + struct ad2s1200_state *st; + struct iio_dev *indio_dev; + int 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 = devm_gpiod_get(&spi->dev, "adi,sample", GPIOD_OUT_LOW); + if (IS_ERR(st->sample)) { + dev_err(&spi->dev, "Failed to claim SAMPLE gpio: err=%ld\n", + PTR_ERR(st->sample)); + return PTR_ERR(st->sample); + } + + st->rdvel = devm_gpiod_get(&spi->dev, "adi,rdvel", GPIOD_OUT_LOW); + if (IS_ERR(st->rdvel)) { + dev_err(&spi->dev, "Failed to claim RDVEL gpio: err=%ld\n", + PTR_ERR(st->rdvel)); + return PTR_ERR(st->rdvel); + } + + 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; + + spi->max_speed_hz = AD2S1200_HZ; + spi->mode = SPI_MODE_3; + ret = spi_setup(spi); + + if (ret < 0) { + dev_err(&spi->dev, "spi_setup failed!\n"); + return ret; + } + + return devm_iio_device_register(&spi->dev, indio_dev); +} + +static const struct of_device_id ad2s1200_of_match[] = { + { .compatible = "adi,ad2s1200", }, + { .compatible = "adi,ad2s1205", }, + { } +}; +MODULE_DEVICE_TABLE(of, ad2s1200_of_match); + +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, + .of_match_table = of_match_ptr(ad2s1200_of_match), + }, + .probe = ad2s1200_probe, + .id_table = ad2s1200_id, +}; +module_spi_driver(ad2s1200_driver); + +MODULE_AUTHOR("David Veenstra <davidjulianveenstra@gmail.com>"); +MODULE_AUTHOR("Graff Yang <graff.yang@gmail.com>"); +MODULE_DESCRIPTION("Analog Devices AD2S1200/1205 Resolver to Digital SPI driver"); +MODULE_LICENSE("GPL v2"); |
