- 根目录:
- drivers
- staging
- iio
- resolver
- ad2s120x.c
/*
* ad2s120x.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 "../iio.h"
#include "../sysfs.h"
#define DRV_NAME "ad2s120x"
/* input pin sample and rdvel is controlled by driver */
#define AD2S120X_PN 2
/* input clock on serial interface */
#define AD2S120X_HZ 8192000
/* clock period in nano second */
#define AD2S120X_TSCLK (1000000000/AD2S120X_HZ)
struct ad2s120x_state {
struct mutex lock;
struct iio_dev *idev;
struct spi_device *sdev;
unsigned short sample;
unsigned short rdvel;
u8 rx[2];
u8 tx[2];
};
static ssize_t ad2s120x_show_pos_vel(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct spi_message msg;
struct spi_transfer xfer;
int ret = 0;
ssize_t len = 0;
u16 pos;
s16 vel;
u8 status;
struct iio_dev *idev = dev_get_drvdata(dev);
struct ad2s120x_state *st = idev->dev_data;
xfer.len = 1;
xfer.tx_buf = st->tx;
xfer.rx_buf = st->rx;
mutex_lock(&st->lock);
gpio_set_value(st->sample, 0);
/* delay (6 * AD2S120X_TSCLK + 20) nano seconds */
udelay(1);
gpio_set_value(st->sample, 1);
spi_message_init(&msg);
spi_message_add_tail(&xfer, &msg);
ret = spi_sync(st->sdev, &msg);
if (ret)
goto error_ret;
status = st->rx[1];
pos = (((u16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
len = sprintf(buf, "%d %c%c%c%c ", pos,
(status & 0x8) ? 'P' : 'V',
(status & 0x4) ? 'd' : '_',
(status & 0x2) ? 'l' : '_',
(status & 0x1) ? '1' : '0');
/* delay 18 ns */
/* ndelay(18); */
gpio_set_value(st->rdvel, 0);
/* ndelay(5);*/
spi_message_init(&msg);
spi_message_add_tail(&xfer, &msg);
ret = spi_sync(st->sdev, &msg);
if (ret)
goto error_ret;
status = st->rx[1];
vel = (st->rx[0] & 0x80) ? 0xf000 : 0;
vel |= (((s16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
len += sprintf(buf + len, "%d %c%c%c%c\n", vel,
(status & 0x8) ? 'P' : 'V',
(status & 0x4) ? 'd' : '_',
(status & 0x2) ? 'l' : '_',
(status & 0x1) ? '1' : '0');
error_ret:
gpio_set_value(st->rdvel, 1);
/* delay (2 * AD2S120X_TSCLK + 20) ns for sample pulse */
udelay(1);
mutex_unlock(&st->lock);
return ret ? ret : len;
}
static ssize_t ad2s120x_show_pos(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct spi_message msg;
struct spi_transfer xfer;
int ret = 0;
ssize_t len = 0;
u16 pos;
u8 status;
struct iio_dev *idev = dev_get_drvdata(dev);
struct ad2s120x_state *st = idev->dev_data;
xfer.len = 1;
xfer.tx_buf = st->tx;
xfer.rx_buf = st->rx;
mutex_lock(&st->lock);
gpio_set_value(st->sample, 0);
/* delay (6 * AD2S120X_TSCLK + 20) nano seconds */
udelay(1);
gpio_set_value(st->sample, 1);
gpio_set_value(st->rdvel, 1);
spi_message_init(&msg);
spi_message_add_tail(&xfer, &msg);
ret = spi_sync(st->sdev, &msg);
if (ret)
goto error_ret;
status = st->rx[1];
pos = (((u16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
len = sprintf(buf, "%d %c%c%c%c ", pos,
(status & 0x8) ? 'P' : 'V',
(status & 0x4) ? 'd' : '_',
(status & 0x2) ? 'l' : '_',
(status & 0x1) ? '1' : '0');
error_ret:
/* delay (2 * AD2S120X_TSCLK + 20) ns for sample pulse */
udelay(1);
mutex_unlock(&st->lock);
return ret ? ret : len;
}
static ssize_t ad2s120x_show_vel(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct spi_message msg;
struct spi_transfer xfer;
int ret = 0;
ssize_t len = 0;
s16 vel;
u8 status;
struct iio_dev *idev = dev_get_drvdata(dev);
struct ad2s120x_state *st = idev->dev_data;
xfer.len = 1;
xfer.tx_buf = st->tx;
xfer.rx_buf = st->rx;
mutex_lock(&st->lock);
gpio_set_value(st->sample, 0);
/* delay (6 * AD2S120X_TSCLK + 20) nano seconds */
udelay(1);
gpio_set_value(st->sample, 1);
gpio_set_value(st->rdvel, 0);
/* ndelay(5);*/
spi_message_init(&msg);
spi_message_add_tail(&xfer, &msg);
ret = spi_sync(st->sdev, &msg);
if (ret)
goto error_ret;
status = st->rx[1];
vel = (st->rx[0] & 0x80) ? 0xf000 : 0;
vel |= (((s16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
len += sprintf(buf + len, "%d %c%c%c%c\n", vel,
(status & 0x8) ? 'P' : 'V',
(status & 0x4) ? 'd' : '_',
(status & 0x2) ? 'l' : '_',
(status & 0x1) ? '1' : '0');
error_ret:
gpio_set_value(st->rdvel, 1);
/* delay (2 * AD2S120X_TSCLK + 20) ns for sample pulse */
udelay(1);
mutex_unlock(&st->lock);
return ret ? ret : len;
}
static IIO_CONST_ATTR(description,
"12-Bit R/D Converter with Reference Oscillator");
static IIO_DEVICE_ATTR(pos_vel, S_IRUGO, ad2s120x_show_pos_vel, NULL, 0);
static IIO_DEVICE_ATTR(pos, S_IRUGO, ad2s120x_show_pos, NULL, 0);
static IIO_DEVICE_ATTR(vel, S_IRUGO, ad2s120x_show_vel, NULL, 0);
static struct attribute *ad2s120x_attributes[] = {
&iio_const_attr_description.dev_attr.attr,
&iio_dev_attr_pos_vel.dev_attr.attr,
&iio_dev_attr_pos.dev_attr.attr,
&iio_dev_attr_vel.dev_attr.attr,
NULL,
};
static const struct attribute_group ad2s120x_attribute_group = {
.name = DRV_NAME,
.attrs = ad2s120x_attributes,
};
static int __devinit ad2s120x_probe(struct spi_device *spi)
{
struct ad2s120x_state *st;
int pn, ret = 0;
unsigned short *pins = spi->dev.platform_data;
for (pn = 0; pn < AD2S120X_PN; pn++) {
if (gpio_request(pins[pn], DRV_NAME)) {
pr_err("%s: request gpio pin %d failed\n",
DRV_NAME, pins[pn]);
goto error_ret;
}
gpio_direction_output(pins[pn], 1);
}
st = kzalloc(sizeof(*st), GFP_KERNEL);
if (st == NULL) {
ret = -ENOMEM;
goto error_ret;
}
spi_set_drvdata(spi, st);
mutex_init(&st->lock);
st->sdev = spi;
st->sample = pins[0];
st->rdvel = pins[1];
st->idev = iio_allocate_device();
if (st->idev == NULL) {
ret = -ENOMEM;
goto error_free_st;
}
st->idev->dev.parent = &spi->dev;
st->idev->num_interrupt_lines = 0;
st->idev->event_attrs = NULL;
st->idev->attrs = &ad2s120x_attribute_group;
st->idev->dev_data = (void *)(st);
st->idev->driver_module = THIS_MODULE;
st->idev->modes = INDIO_DIRECT_MODE;
ret = iio_device_register(st->idev);
if (ret)
goto error_free_dev;
spi->max_speed_hz = AD2S120X_HZ;
spi->mode = SPI_MODE_3;
spi_setup(spi);
return 0;
error_free_dev:
iio_free_device(st->idev);
error_free_st:
kfree(st);
error_ret:
for (--pn; pn >= 0; pn--)
gpio_free(pins[pn]);
return ret;
}
static int __devexit ad2s120x_remove(struct spi_device *spi)
{
struct ad2s120x_state *st = spi_get_drvdata(spi);
iio_device_unregister(st->idev);
kfree(st);
return 0;
}
static struct spi_driver ad2s120x_driver = {
.driver = {
.name = DRV_NAME,
.owner = THIS_MODULE,
},
.probe = ad2s120x_probe,
.remove = __devexit_p(ad2s120x_remove),
};
static __init int ad2s120x_spi_init(void)
{
return spi_register_driver(&ad2s120x_driver);
}
module_init(ad2s120x_spi_init);
static __exit void ad2s120x_spi_exit(void)
{
spi_unregister_driver(&ad2s120x_driver);
}
module_exit(ad2s120x_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");