drivers/staging/iio/resolver/ad2s120x.c - nest-cam/v179/linux - Git at Google

 /*
  * 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");
	/*
	* 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");