staging: iio: resolver: new driver for AD2S1200/1205 devices

Signed-off-by: Graf Yang <graf.yang@analog.com>
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/iio/resolver/Kconfig

@@ -9,3 +9,11 @@ config AD2S90
 	help
 	  Say yes here to build support for Analog Devices spi resolver
 	  to digital converters, ad2s90, provides direct access via sysfs.
+
+config AD2S120X
+	tristate "Analog Devices ad2s120x driver"
+	depends on SPI
+	help
+	  Say yes here to build support for Analog Devices spi resolver
+	  to digital converters, ad2s1200 and ad2s1205, provides direct access
+	  via sysfs.

drivers/staging/iio/resolver/Makefile

@@ -3,3 +3,4 @@
 #
 
 obj-$(CONFIG_AD2S90) += ad2s90.o
+obj-$(CONFIG_AD2S120X) += ad2s120x.o

drivers/staging/iio/resolver/ad2s120x.c

@@ -0,0 +1,310 @@
+/*
+ * 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");