1 files changed, 177 insertions, 0 deletions

diff --git a/drivers/staging/iio/resolver/ad2s120x.c b/drivers/staging/iio/resolver/ad2s120x.c
new file mode 100644
index 00000000000..bed4c725f2d
--- /dev/null
+++ b/drivers/staging/iio/resolver/ad2s120x.c
@@ -0,0 +1,177 @@
+/*
+ * 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 spi_device *sdev;
+        int sample;
+        int rdvel;
+        u8 rx[2] ____cacheline_aligned;
+};
+
+static ssize_t ad2s120x_show_val(struct device *dev,
+                        struct device_attribute *attr, char *buf)
+{
+        int ret = 0;
+        ssize_t len = 0;
+        u16 pos;
+        s16 vel;
+        u8 status;
+        struct ad2s120x_state *st = iio_priv(dev_get_drvdata(dev));
+        struct iio_dev_attr *iattr = to_iio_dev_attr(attr);
+
+        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, iattr->address);
+        ret = spi_read(st->sdev, st->rx, 2);
+        if (ret < 0)
+                goto error_ret;
+        status = st->rx[1];
+        if (iattr->address)
+                pos = (((u16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
+        else {
+                vel = (st->rx[0] & 0x80) ? 0xf000 : 0;
+                vel |= (((s16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
+        }
+        len = sprintf(buf, "%d %c%c%c%c ", iattr->address ? pos : vel,
+                                (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 IIO_DEVICE_ATTR(pos, S_IRUGO, ad2s120x_show_val, NULL, 1);
+static IIO_DEVICE_ATTR(vel, S_IRUGO, ad2s120x_show_val, NULL, 0);
+
+static struct attribute *ad2s120x_attributes[] = {
+        &iio_dev_attr_pos.dev_attr.attr,
+        &iio_dev_attr_vel.dev_attr.attr,
+        NULL,
+};
+
+static const struct attribute_group ad2s120x_attribute_group = {
+        .attrs = ad2s120x_attributes,
+};
+
+static const struct iio_info ad2s120x_info = {
+        .attrs = &ad2s120x_attribute_group,
+        .driver_module = THIS_MODULE,
+};
+
+static int __devinit ad2s120x_probe(struct spi_device *spi)
+{
+        struct ad2s120x_state *st;
+        struct iio_dev *indio_dev;
+        int pn, ret = 0;
+        unsigned short *pins = spi->dev.platform_data;
+
+        for (pn = 0; pn < AD2S120X_PN; pn++)
+                if (gpio_request_one(pins[pn], GPIOF_DIR_OUT, DRV_NAME)) {
+                        pr_err("%s: request gpio pin %d failed\n",
+                                                DRV_NAME, pins[pn]);
+                        goto error_ret;
+                }
+        indio_dev = iio_allocate_device(sizeof(*st));
+        if (indio_dev == NULL) {
+                ret = -ENOMEM;
+                goto error_ret;
+        }
+        spi_set_drvdata(spi, indio_dev);
+        st = iio_priv(indio_dev);
+        mutex_init(&st->lock);
+        st->sdev = spi;
+        st->sample = pins[0];
+        st->rdvel = pins[1];
+
+        indio_dev->dev.parent = &spi->dev;
+        indio_dev->info = &ad2s120x_info;
+        indio_dev->modes = INDIO_DIRECT_MODE;
+
+        ret = iio_device_register(indio_dev);
+        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(indio_dev);
+error_ret:
+        for (--pn; pn >= 0; pn--)
+                gpio_free(pins[pn]);
+        return ret;
+}
+
+static int __devexit ad2s120x_remove(struct spi_device *spi)
+{
+        iio_device_unregister(spi_get_drvdata(spi));
+
+        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");