Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / drivers / staging / iio / resolver / ad2s1200.c

diff --git a/kernel/drivers/staging/iio/resolver/ad2s1200.c b/kernel/drivers/staging/iio/resolver/ad2s1200.c
new file mode 100644 (file)
index 0000000..c17893b
--- /dev/null
+++ b/kernel/drivers/staging/iio/resolver/ad2s1200.c
@@ -0,0 +1,167 @@
+/*
+ * ad2s1200.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 <linux/module.h>
+#include <linux/bitops.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+#define DRV_NAME "ad2s1200"
+
+/* input pin sample and rdvel is controlled by driver */
+#define AD2S1200_PN    2
+
+/* input clock on serial interface */
+#define AD2S1200_HZ    8192000
+/* clock period in nano second */
+#define AD2S1200_TSCLK (1000000000/AD2S1200_HZ)
+
+struct ad2s1200_state {
+       struct mutex lock;
+       struct spi_device *sdev;
+       int sample;
+       int rdvel;
+       u8 rx[2] ____cacheline_aligned;
+};
+
+static int ad2s1200_read_raw(struct iio_dev *indio_dev,
+                          struct iio_chan_spec const *chan,
+                          int *val,
+                          int *val2,
+                          long m)
+{
+       int ret = 0;
+       s16 vel;
+       struct ad2s1200_state *st = iio_priv(indio_dev);
+
+       mutex_lock(&st->lock);
+       gpio_set_value(st->sample, 0);
+       /* delay (6 * AD2S1200_TSCLK + 20) nano seconds */
+       udelay(1);
+       gpio_set_value(st->sample, 1);
+       gpio_set_value(st->rdvel, !!(chan->type == IIO_ANGL));
+       ret = spi_read(st->sdev, st->rx, 2);
+       if (ret < 0) {
+               mutex_unlock(&st->lock);
+               return ret;
+       }
+
+       switch (chan->type) {
+       case IIO_ANGL:
+               *val = (((u16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
+               break;
+       case IIO_ANGL_VEL:
+               vel = (((s16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
+               vel = sign_extend32(vel, 11);
+               *val = vel;
+               break;
+       default:
+               mutex_unlock(&st->lock);
+               return -EINVAL;
+       }
+       /* delay (2 * AD2S1200_TSCLK + 20) ns for sample pulse */
+       udelay(1);
+       mutex_unlock(&st->lock);
+       return IIO_VAL_INT;
+}
+
+static const struct iio_chan_spec ad2s1200_channels[] = {
+       {
+               .type = IIO_ANGL,
+               .indexed = 1,
+               .channel = 0,
+               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+       }, {
+               .type = IIO_ANGL_VEL,
+               .indexed = 1,
+               .channel = 0,
+               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+       }
+};
+
+static const struct iio_info ad2s1200_info = {
+       .read_raw = &ad2s1200_read_raw,
+       .driver_module = THIS_MODULE,
+};
+
+static int ad2s1200_probe(struct spi_device *spi)
+{
+       struct ad2s1200_state *st;
+       struct iio_dev *indio_dev;
+       int pn, ret = 0;
+       unsigned short *pins = spi->dev.platform_data;
+
+       for (pn = 0; pn < AD2S1200_PN; pn++) {
+               ret = devm_gpio_request_one(&spi->dev, pins[pn], GPIOF_DIR_OUT,
+                                           DRV_NAME);
+               if (ret) {
+                       dev_err(&spi->dev, "request gpio pin %d failed\n",
+                                                       pins[pn]);
+                       return ret;
+               }
+       }
+       indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
+       if (!indio_dev)
+               return -ENOMEM;
+       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 = &ad2s1200_info;
+       indio_dev->modes = INDIO_DIRECT_MODE;
+       indio_dev->channels = ad2s1200_channels;
+       indio_dev->num_channels = ARRAY_SIZE(ad2s1200_channels);
+       indio_dev->name = spi_get_device_id(spi)->name;
+
+       ret = devm_iio_device_register(&spi->dev, indio_dev);
+       if (ret)
+               return ret;
+
+       spi->max_speed_hz = AD2S1200_HZ;
+       spi->mode = SPI_MODE_3;
+       spi_setup(spi);
+
+       return 0;
+}
+
+static const struct spi_device_id ad2s1200_id[] = {
+       { "ad2s1200" },
+       { "ad2s1205" },
+       {}
+};
+MODULE_DEVICE_TABLE(spi, ad2s1200_id);
+
+static struct spi_driver ad2s1200_driver = {
+       .driver = {
+               .name = DRV_NAME,
+               .owner = THIS_MODULE,
+       },
+       .probe = ad2s1200_probe,
+       .id_table = ad2s1200_id,
+};
+module_spi_driver(ad2s1200_driver);
+
+MODULE_AUTHOR("Graff Yang <graff.yang@gmail.com>");
+MODULE_DESCRIPTION("Analog Devices AD2S1200/1205 Resolver to Digital SPI driver");
+MODULE_LICENSE("GPL v2");