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 #include <linux/module.h>
  18
  19 #include "../iio.h"
  20 #include "../sysfs.h"
  21
  22 #define DRV_NAME "ad5930"
  23
  24 #define value_mask (u16)0xf000
  25 #define addr_shift 12
  26
  27 /* Register format: 4 bits addr + 12 bits value */
  28 struct ad5903_config {
  29         u16 control;
  30         u16 incnum;
  31         u16 frqdelt[2];
  32         u16 incitvl;
  33         u16 buritvl;
  34         u16 strtfrq[2];
  35 };
  36
  37 struct ad5930_state {
  38         struct mutex lock;
  39         struct spi_device *sdev;
  40 };
  41
  42 static ssize_t ad5930_set_parameter(struct device *dev,
  43                                         struct device_attribute *attr,
  44                                         const char *buf,
  45                                         size_t len)
  46 {
  47         struct spi_message msg;
  48         struct spi_transfer xfer;
  49         int ret;
  50         struct ad5903_config *config = (struct ad5903_config *)buf;
  51         struct iio_dev *idev = dev_get_drvdata(dev);
  52         struct ad5930_state *st = iio_priv(idev);
  53
  54         config->control = (config->control & ~value_mask);
  55         config->incnum = (config->control & ~value_mask) | (1 << addr_shift);
  56         config->frqdelt[0] = (config->control & ~value_mask) | (2 << addr_shift);
  57         config->frqdelt[1] = (config->control & ~value_mask) | 3 << addr_shift;
  58         config->incitvl = (config->control & ~value_mask) | 4 << addr_shift;
  59         config->buritvl = (config->control & ~value_mask) | 8 << addr_shift;
  60         config->strtfrq[0] = (config->control & ~value_mask) | 0xc << addr_shift;
  61         config->strtfrq[1] = (config->control & ~value_mask) | 0xd << addr_shift;
  62
  63         xfer.len = len;
  64         xfer.tx_buf = config;
  65         mutex_lock(&st->lock);
  66
  67         spi_message_init(&msg);
  68         spi_message_add_tail(&xfer, &msg);
  69         ret = spi_sync(st->sdev, &msg);
  70         if (ret)
  71                 goto error_ret;
  72 error_ret:
  73         mutex_unlock(&st->lock);
  74
  75         return ret ? ret : len;
  76 }
  77
  78 static IIO_DEVICE_ATTR(dds, S_IWUSR, NULL, ad5930_set_parameter, 0);
  79
  80 static struct attribute *ad5930_attributes[] = {
  81         &iio_dev_attr_dds.dev_attr.attr,
  82         NULL,
  83 };
  84
  85 static const struct attribute_group ad5930_attribute_group = {
  86         .attrs = ad5930_attributes,
  87 };
  88
  89 static const struct iio_info ad5930_info = {
  90         .attrs = &ad5930_attribute_group,
  91         .driver_module = THIS_MODULE,
  92 };
  93
  94 static int __devinit ad5930_probe(struct spi_device *spi)
  95 {
  96         struct ad5930_state *st;
  97         struct iio_dev *idev;
  98         int ret = 0;
  99
 100         idev = iio_allocate_device(sizeof(*st));
 101         if (idev == NULL) {
 102                 ret = -ENOMEM;
 103                 goto error_ret;
 104         }
 105         spi_set_drvdata(spi, idev);
 106         st = iio_priv(idev);
 107
 108         mutex_init(&st->lock);
 109         st->sdev = spi;
 110         idev->dev.parent = &spi->dev;
 111         idev->info = &ad5930_info;
 112         idev->modes = INDIO_DIRECT_MODE;
 113
 114         ret = iio_device_register(idev);
 115         if (ret)
 116                 goto error_free_dev;
 117         spi->max_speed_hz = 2000000;
 118         spi->mode = SPI_MODE_3;
 119         spi->bits_per_word = 16;
 120         spi_setup(spi);
 121
 122         return 0;
 123
 124 error_free_dev:
 125         iio_free_device(idev);
 126 error_ret:
 127         return ret;
 128 }
 129
 130 static int __devexit ad5930_remove(struct spi_device *spi)
 131 {
 132         iio_device_unregister(spi_get_drvdata(spi));
 133         iio_free_device(spi_get_drvdata(spi));
 134
 135         return 0;
 136 }
 137
 138 static struct spi_driver ad5930_driver = {
 139         .driver = {
 140                 .name = DRV_NAME,
 141                 .owner = THIS_MODULE,
 142         },
 143         .probe = ad5930_probe,
 144         .remove = __devexit_p(ad5930_remove),
 145 };
 146
 147 static __init int ad5930_spi_init(void)
 148 {
 149         return spi_register_driver(&ad5930_driver);
 150 }
 151 module_init(ad5930_spi_init);
 152
 153 static __exit void ad5930_spi_exit(void)
 154 {
 155         spi_unregister_driver(&ad5930_driver);
 156 }
 157 module_exit(ad5930_spi_exit);
 158
 159 MODULE_AUTHOR("Cliff Cai");
 160 MODULE_DESCRIPTION("Analog Devices ad5930 driver");
 161 MODULE_LICENSE("GPL v2");