drivers/staging/iio/dds/ad5930.c

   1 /*
   2  * Driver for ADI Direct Digital Synthesis ad5930
   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 "ad5930"
  22
  23 #define value_mask (u16)0xf000
  24 #define addr_shift 12
  25
  26 /* Register format: 4 bits addr + 12 bits value */
  27 struct ad5903_config {
  28         u16 control;
  29         u16 incnum;
  30         u16 frqdelt[2];
  31         u16 incitvl;
  32         u16 buritvl;
  33         u16 strtfrq[2];
  34 };
  35
  36 struct ad5930_state {
  37         struct mutex lock;
  38         struct spi_device *sdev;
  39 };
  40
  41 static ssize_t ad5930_set_parameter(struct device *dev,
  42                                         struct device_attribute *attr,
  43                                         const char *buf,
  44                                         size_t len)
  45 {
  46         struct spi_message msg;
  47         struct spi_transfer xfer;
  48         int ret;
  49         struct ad5903_config *config = (struct ad5903_config *)buf;
  50         struct iio_dev *idev = dev_get_drvdata(dev);
  51         struct ad5930_state *st = iio_priv(idev);
  52
  53         config->control = (config->control & ~value_mask);
  54         config->incnum = (config->control & ~value_mask) | (1 << addr_shift);
  55         config->frqdelt[0] = (config->control & ~value_mask) | (2 << addr_shift);
  56         config->frqdelt[1] = (config->control & ~value_mask) | 3 << addr_shift;
  57         config->incitvl = (config->control & ~value_mask) | 4 << addr_shift;
  58         config->buritvl = (config->control & ~value_mask) | 8 << addr_shift;
  59         config->strtfrq[0] = (config->control & ~value_mask) | 0xc << addr_shift;
  60         config->strtfrq[1] = (config->control & ~value_mask) | 0xd << addr_shift;
  61
  62         xfer.len = len;
  63         xfer.tx_buf = config;
  64         mutex_lock(&st->lock);
  65
  66         spi_message_init(&msg);
  67         spi_message_add_tail(&xfer, &msg);
  68         ret = spi_sync(st->sdev, &msg);
  69         if (ret)
  70                 goto error_ret;
  71 error_ret:
  72         mutex_unlock(&st->lock);
  73
  74         return ret ? ret : len;
  75 }
  76
  77 static IIO_DEVICE_ATTR(dds, S_IWUSR, NULL, ad5930_set_parameter, 0);
  78
  79 static struct attribute *ad5930_attributes[] = {
  80         &iio_dev_attr_dds.dev_attr.attr,
  81         NULL,
  82 };
  83
  84 static const struct attribute_group ad5930_attribute_group = {
  85         .attrs = ad5930_attributes,
  86 };
  87
  88 static const struct iio_info ad5930_info = {
  89         .attrs = &ad5930_attribute_group,
  90         .driver_module = THIS_MODULE,
  91 };
  92
  93 static int __devinit ad5930_probe(struct spi_device *spi)
  94 {
  95         struct ad5930_state *st;
  96         struct iio_dev *idev;
  97         int ret = 0;
  98
  99         idev = iio_allocate_device(sizeof(*st));
 100         if (idev == NULL) {
 101                 ret = -ENOMEM;
 102                 goto error_ret;
 103         }
 104         spi_set_drvdata(spi, idev);
 105         st = iio_priv(idev);
 106
 107         mutex_init(&st->lock);
 108         st->sdev = spi;
 109         idev->dev.parent = &spi->dev;
 110         idev->info = &ad5930_info;
 111         idev->modes = INDIO_DIRECT_MODE;
 112
 113         ret = iio_device_register(idev);
 114         if (ret)
 115                 goto error_free_dev;
 116         spi->max_speed_hz = 2000000;
 117         spi->mode = SPI_MODE_3;
 118         spi->bits_per_word = 16;
 119         spi_setup(spi);
 120
 121         return 0;
 122
 123 error_free_dev:
 124         iio_free_device(idev);
 125 error_ret:
 126         return ret;
 127 }
 128
 129 static int __devexit ad5930_remove(struct spi_device *spi)
 130 {
 131         iio_device_unregister(spi_get_drvdata(spi));
 132
 133         return 0;
 134 }
 135
 136 static struct spi_driver ad5930_driver = {
 137         .driver = {
 138                 .name = DRV_NAME,
 139                 .owner = THIS_MODULE,
 140         },
 141         .probe = ad5930_probe,
 142         .remove = __devexit_p(ad5930_remove),
 143 };
 144
 145 static __init int ad5930_spi_init(void)
 146 {
 147         return spi_register_driver(&ad5930_driver);
 148 }
 149 module_init(ad5930_spi_init);
 150
 151 static __exit void ad5930_spi_exit(void)
 152 {
 153         spi_unregister_driver(&ad5930_driver);
 154 }
 155 module_exit(ad5930_spi_exit);
 156
 157 MODULE_AUTHOR("Cliff Cai");
 158 MODULE_DESCRIPTION("Analog Devices ad5930 driver");
 159 MODULE_LICENSE("GPL v2");