| /* |
| * 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 "../iio.h" |
| #include "../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 = (vel << 4) >> 4; |
| *val = vel; |
| 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, |
| }, { |
| .type = IIO_ANGL_VEL, |
| .indexed = 1, |
| .channel = 0, |
| } |
| }; |
| |
| static const struct iio_info ad2s1200_info = { |
| .read_raw = &ad2s1200_read_raw, |
| .driver_module = THIS_MODULE, |
| }; |
| |
| static int __devinit 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++) |
| if (gpio_request_one(pins[pn], GPIOF_DIR_OUT, DRV_NAME)) { |
| pr_err("%s: request gpio pin %d failed\n", |
| DRV_NAME, pins[pn]); |
| goto error_ret; |
| } |
| indio_dev = iio_allocate_device(sizeof(*st)); |
| if (indio_dev == NULL) { |
| ret = -ENOMEM; |
| goto error_ret; |
| } |
| 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 = iio_device_register(indio_dev); |
| if (ret) |
| goto error_free_dev; |
| |
| spi->max_speed_hz = AD2S1200_HZ; |
| spi->mode = SPI_MODE_3; |
| spi_setup(spi); |
| |
| return 0; |
| |
| error_free_dev: |
| iio_free_device(indio_dev); |
| error_ret: |
| for (--pn; pn >= 0; pn--) |
| gpio_free(pins[pn]); |
| return ret; |
| } |
| |
| static int __devexit ad2s1200_remove(struct spi_device *spi) |
| { |
| iio_device_unregister(spi_get_drvdata(spi)); |
| iio_free_device(spi_get_drvdata(spi)); |
| |
| return 0; |
| } |
| |
| static const struct spi_device_id ad2s1200_id[] = { |
| { "ad2s1200" }, |
| { "ad2s1205" }, |
| {} |
| }; |
| |
| static struct spi_driver ad2s1200_driver = { |
| .driver = { |
| .name = DRV_NAME, |
| .owner = THIS_MODULE, |
| }, |
| .probe = ad2s1200_probe, |
| .remove = __devexit_p(ad2s1200_remove), |
| .id_table = ad2s1200_id, |
| }; |
| |
| static __init int ad2s1200_spi_init(void) |
| { |
| return spi_register_driver(&ad2s1200_driver); |
| } |
| module_init(ad2s1200_spi_init); |
| |
| static __exit void ad2s1200_spi_exit(void) |
| { |
| spi_unregister_driver(&ad2s1200_driver); |
| } |
| module_exit(ad2s1200_spi_exit); |
| |
| MODULE_AUTHOR("Graff Yang <graff.yang@gmail.com>"); |
| MODULE_DESCRIPTION("Analog Devices AD2S1200/1205 Resolver to Digital SPI driver"); |
| MODULE_LICENSE("GPL v2"); |