drivers/staging/iio/dds/ad9850.c

   1 /*
   2  * Driver for ADI Direct Digital Synthesis ad9850
   3  *
   4  * Copyright (c) 2010-2010 Analog Devices Inc.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  */
  11 #include <linux/types.h>
  12 #include <linux/mutex.h>
  13 #include <linux/device.h>
  14 #include <linux/spi/spi.h>
  15 #include <linux/slab.h>
  16 #include <linux/sysfs.h>
  17 #include <linux/module.h>
  18
  19 #include "../iio.h"
  20 #include "../sysfs.h"
  21
  22 #define DRV_NAME "ad9850"
  23
  24 #define value_mask (u16)0xf000
  25 #define addr_shift 12
  26
  27 /* Register format: 4 bits addr + 12 bits value */
  28 struct ad9850_config {
  29         u8 control[5];
  30 };
  31
  32 struct ad9850_state {
  33         struct mutex lock;
  34         struct spi_device *sdev;
  35 };
  36
  37 static ssize_t ad9850_set_parameter(struct device *dev,
  38                                         struct device_attribute *attr,
  39                                         const char *buf,
  40                                         size_t len)
  41 {
  42         struct spi_message msg;
  43         struct spi_transfer xfer;
  44         int ret;
  45         struct ad9850_config *config = (struct ad9850_config *)buf;
  46         struct iio_dev *idev = dev_get_drvdata(dev);
  47         struct ad9850_state *st = iio_priv(idev);
  48
  49         xfer.len = len;
  50         xfer.tx_buf = config;
  51         mutex_lock(&st->lock);
  52
  53         spi_message_init(&msg);
  54         spi_message_add_tail(&xfer, &msg);
  55         ret = spi_sync(st->sdev, &msg);
  56         if (ret)
  57                 goto error_ret;
  58 error_ret:
  59         mutex_unlock(&st->lock);
  60
  61         return ret ? ret : len;
  62 }
  63
  64 static IIO_DEVICE_ATTR(dds, S_IWUSR, NULL, ad9850_set_parameter, 0);
  65
  66 static struct attribute *ad9850_attributes[] = {
  67         &iio_dev_attr_dds.dev_attr.attr,
  68         NULL,
  69 };
  70
  71 static const struct attribute_group ad9850_attribute_group = {
  72         .attrs = ad9850_attributes,
  73 };
  74
  75 static const struct iio_info ad9850_info = {
  76         .attrs = &ad9850_attribute_group,
  77         .driver_module = THIS_MODULE,
  78 };
  79
  80 static int __devinit ad9850_probe(struct spi_device *spi)
  81 {
  82         struct ad9850_state *st;
  83         struct iio_dev *idev;
  84         int ret = 0;
  85
  86         idev = iio_allocate_device(sizeof(*st));
  87         if (idev == NULL) {
  88                 ret = -ENOMEM;
  89                 goto error_ret;
  90         }
  91         spi_set_drvdata(spi, idev);
  92         st = iio_priv(idev);
  93         mutex_init(&st->lock);
  94         st->sdev = spi;
  95
  96         idev->dev.parent = &spi->dev;
  97         idev->info = &ad9850_info;
  98         idev->modes = INDIO_DIRECT_MODE;
  99
 100         ret = iio_device_register(idev);
 101         if (ret)
 102                 goto error_free_dev;
 103         spi->max_speed_hz = 2000000;
 104         spi->mode = SPI_MODE_3;
 105         spi->bits_per_word = 16;
 106         spi_setup(spi);
 107
 108         return 0;
 109
 110 error_free_dev:
 111         iio_free_device(idev);
 112 error_ret:
 113         return ret;
 114 }
 115
 116 static int __devexit ad9850_remove(struct spi_device *spi)
 117 {
 118         iio_device_unregister(spi_get_drvdata(spi));
 119         iio_free_device(spi_get_drvdata(spi));
 120
 121         return 0;
 122 }
 123
 124 static struct spi_driver ad9850_driver = {
 125         .driver = {
 126                 .name = DRV_NAME,
 127                 .owner = THIS_MODULE,
 128         },
 129         .probe = ad9850_probe,
 130         .remove = __devexit_p(ad9850_remove),
 131 };
 132 module_spi_driver(ad9850_driver);
 133
 134 MODULE_AUTHOR("Cliff Cai");
 135 MODULE_DESCRIPTION("Analog Devices ad9850 driver");
 136 MODULE_LICENSE("GPL v2");
 137 MODULE_ALIAS("spi:" DRV_NAME);