--- /dev/null
+/*
+ * 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");
projects / mv-sheeva.git / blobdiff