179 lines
4.2 KiB
C
179 lines
4.2 KiB
C
/*
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* ad2s120x.c simple support for the ADI Resolver to Digital Converters: AD2S1200/1205
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*
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* Copyright (c) 2010-2010 Analog Devices Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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#include <linux/types.h>
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#include <linux/mutex.h>
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#include <linux/device.h>
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#include <linux/spi/spi.h>
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#include <linux/slab.h>
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#include <linux/sysfs.h>
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#include <linux/delay.h>
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#include <linux/gpio.h>
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#include <linux/module.h>
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#include "../iio.h"
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#include "../sysfs.h"
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#define DRV_NAME "ad2s120x"
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/* input pin sample and rdvel is controlled by driver */
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#define AD2S120X_PN 2
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/* input clock on serial interface */
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#define AD2S120X_HZ 8192000
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/* clock period in nano second */
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#define AD2S120X_TSCLK (1000000000/AD2S120X_HZ)
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struct ad2s120x_state {
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struct mutex lock;
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struct spi_device *sdev;
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int sample;
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int rdvel;
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u8 rx[2] ____cacheline_aligned;
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};
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static ssize_t ad2s120x_show_val(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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int ret = 0;
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ssize_t len = 0;
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u16 pos;
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s16 vel;
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u8 status;
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struct ad2s120x_state *st = iio_priv(dev_get_drvdata(dev));
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struct iio_dev_attr *iattr = to_iio_dev_attr(attr);
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mutex_lock(&st->lock);
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gpio_set_value(st->sample, 0);
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/* delay (6 * AD2S120X_TSCLK + 20) nano seconds */
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udelay(1);
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gpio_set_value(st->sample, 1);
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gpio_set_value(st->rdvel, iattr->address);
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ret = spi_read(st->sdev, st->rx, 2);
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if (ret < 0)
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goto error_ret;
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status = st->rx[1];
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if (iattr->address)
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pos = (((u16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
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else {
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vel = (st->rx[0] & 0x80) ? 0xf000 : 0;
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vel |= (((s16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
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}
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len = sprintf(buf, "%d %c%c%c%c ", iattr->address ? pos : vel,
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(status & 0x8) ? 'P' : 'V',
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(status & 0x4) ? 'd' : '_',
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(status & 0x2) ? 'l' : '_',
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(status & 0x1) ? '1' : '0');
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error_ret:
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/* delay (2 * AD2S120X_TSCLK + 20) ns for sample pulse */
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udelay(1);
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mutex_unlock(&st->lock);
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return ret ? ret : len;
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}
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static IIO_DEVICE_ATTR(pos, S_IRUGO, ad2s120x_show_val, NULL, 1);
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static IIO_DEVICE_ATTR(vel, S_IRUGO, ad2s120x_show_val, NULL, 0);
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static struct attribute *ad2s120x_attributes[] = {
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&iio_dev_attr_pos.dev_attr.attr,
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&iio_dev_attr_vel.dev_attr.attr,
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NULL,
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};
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static const struct attribute_group ad2s120x_attribute_group = {
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.attrs = ad2s120x_attributes,
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};
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static const struct iio_info ad2s120x_info = {
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.attrs = &ad2s120x_attribute_group,
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.driver_module = THIS_MODULE,
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};
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static int __devinit ad2s120x_probe(struct spi_device *spi)
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{
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struct ad2s120x_state *st;
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struct iio_dev *indio_dev;
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int pn, ret = 0;
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unsigned short *pins = spi->dev.platform_data;
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for (pn = 0; pn < AD2S120X_PN; pn++)
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if (gpio_request_one(pins[pn], GPIOF_DIR_OUT, DRV_NAME)) {
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pr_err("%s: request gpio pin %d failed\n",
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DRV_NAME, pins[pn]);
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goto error_ret;
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}
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indio_dev = iio_allocate_device(sizeof(*st));
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if (indio_dev == NULL) {
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ret = -ENOMEM;
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goto error_ret;
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}
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spi_set_drvdata(spi, indio_dev);
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st = iio_priv(indio_dev);
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mutex_init(&st->lock);
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st->sdev = spi;
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st->sample = pins[0];
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st->rdvel = pins[1];
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indio_dev->dev.parent = &spi->dev;
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indio_dev->info = &ad2s120x_info;
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indio_dev->modes = INDIO_DIRECT_MODE;
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ret = iio_device_register(indio_dev);
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if (ret)
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goto error_free_dev;
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spi->max_speed_hz = AD2S120X_HZ;
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spi->mode = SPI_MODE_3;
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spi_setup(spi);
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return 0;
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error_free_dev:
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iio_free_device(indio_dev);
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error_ret:
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for (--pn; pn >= 0; pn--)
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gpio_free(pins[pn]);
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return ret;
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}
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static int __devexit ad2s120x_remove(struct spi_device *spi)
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{
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iio_device_unregister(spi_get_drvdata(spi));
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return 0;
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}
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static struct spi_driver ad2s120x_driver = {
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.driver = {
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.name = DRV_NAME,
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.owner = THIS_MODULE,
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},
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.probe = ad2s120x_probe,
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.remove = __devexit_p(ad2s120x_remove),
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};
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static __init int ad2s120x_spi_init(void)
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{
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return spi_register_driver(&ad2s120x_driver);
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}
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module_init(ad2s120x_spi_init);
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static __exit void ad2s120x_spi_exit(void)
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{
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spi_unregister_driver(&ad2s120x_driver);
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}
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module_exit(ad2s120x_spi_exit);
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MODULE_AUTHOR("Graff Yang <graff.yang@gmail.com>");
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MODULE_DESCRIPTION("Analog Devices AD2S1200/1205 Resolver to Digital SPI driver");
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MODULE_LICENSE("GPL v2");
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