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
  18 #include "../iio.h"
  19 #include "../sysfs.h"
  20
  21 #define DRV_NAME "ad9850"
  22
  23 #define value_mask (u16)0xf000
  24 #define addr_shift 12
  25
  26 /* Register format: 4 bits addr + 12 bits value */
  27 struct ad9850_config {
  28         u8 control[5];
  29 };
  30
  31 struct ad9850_state {
  32         struct mutex lock;
  33         struct spi_device *sdev;
  34 };
  35
  36 static ssize_t ad9850_set_parameter(struct device *dev,
  37                                         struct device_attribute *attr,
  38                                         const char *buf,
  39                                         size_t len)
  40 {
  41         struct spi_message msg;
  42         struct spi_transfer xfer;
  43         int ret;
  44         struct ad9850_config *config = (struct ad9850_config *)buf;
  45         struct iio_dev *idev = dev_get_drvdata(dev);
  46         struct ad9850_state *st = iio_priv(idev);
  47
  48         xfer.len = len;
  49         xfer.tx_buf = config;
  50         mutex_lock(&st->lock);
  51
  52         spi_message_init(&msg);
  53         spi_message_add_tail(&xfer, &msg);
  54         ret = spi_sync(st->sdev, &msg);
  55         if (ret)
  56                 goto error_ret;
  57 error_ret:
  58         mutex_unlock(&st->lock);
  59
  60         return ret ? ret : len;
  61 }
  62
  63 static IIO_DEVICE_ATTR(dds, S_IWUSR, NULL, ad9850_set_parameter, 0);
  64
  65 static struct attribute *ad9850_attributes[] = {
  66         &iio_dev_attr_dds.dev_attr.attr,
  67         NULL,
  68 };
  69
  70 static const struct attribute_group ad9850_attribute_group = {
  71         .attrs = ad9850_attributes,
  72 };
  73
  74 static const struct iio_info ad9850_info = {
  75         .attrs = &ad9850_attribute_group,
  76         .driver_module = THIS_MODULE,
  77 };
  78
  79 static int __devinit ad9850_probe(struct spi_device *spi)
  80 {
  81         struct ad9850_state *st;
  82         struct iio_dev *idev;
  83         int ret = 0;
  84
  85         idev = iio_allocate_device(sizeof(*st));
  86         if (idev == NULL) {
  87                 ret = -ENOMEM;
  88                 goto error_ret;
  89         }
  90         spi_set_drvdata(spi, idev);
  91         st = iio_priv(idev);
  92         mutex_init(&st->lock);
  93         st->sdev = spi;
  94
  95         idev->dev.parent = &spi->dev;
  96         idev->info = &ad9850_info;
  97         idev->modes = INDIO_DIRECT_MODE;
  98
  99         ret = iio_device_register(idev);
 100         if (ret)
 101                 goto error_free_dev;
 102         spi->max_speed_hz = 2000000;
 103         spi->mode = SPI_MODE_3;
 104         spi->bits_per_word = 16;
 105         spi_setup(spi);
 106
 107         return 0;
 108
 109 error_free_dev:
 110         iio_free_device(idev);
 111 error_ret:
 112         return ret;
 113 }
 114
 115 static int __devexit ad9850_remove(struct spi_device *spi)
 116 {
 117         iio_device_unregister(spi_get_drvdata(spi));
 118
 119         return 0;
 120 }
 121
 122 static struct spi_driver ad9850_driver = {
 123         .driver = {
 124                 .name = DRV_NAME,
 125                 .owner = THIS_MODULE,
 126         },
 127         .probe = ad9850_probe,
 128         .remove = __devexit_p(ad9850_remove),
 129 };
 130
 131 static __init int ad9850_spi_init(void)
 132 {
 133         return spi_register_driver(&ad9850_driver);
 134 }
 135 module_init(ad9850_spi_init);
 136
 137 static __exit void ad9850_spi_exit(void)
 138 {
 139         spi_unregister_driver(&ad9850_driver);
 140 }
 141 module_exit(ad9850_spi_exit);
 142
 143 MODULE_AUTHOR("Cliff Cai");
 144 MODULE_DESCRIPTION("Analog Devices ad9850 driver");
 145 MODULE_LICENSE("GPL v2");