drivers/staging/iio/frequency/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 <linux/iio/iio.h>
  20 #include <linux/iio/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_transfer xfer;
  43         int ret;
  44         struct ad9850_config *config = (struct ad9850_config *)buf;
  45         struct iio_dev *idev = dev_to_iio_dev(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         ret = spi_sync_transfer(st->sdev, &xfer, 1);
  53         if (ret)
  54                 goto error_ret;
  55 error_ret:
  56         mutex_unlock(&st->lock);
  57
  58         return ret ? ret : len;
  59 }
  60
  61 static IIO_DEVICE_ATTR(dds, S_IWUSR, NULL, ad9850_set_parameter, 0);
  62
  63 static struct attribute *ad9850_attributes[] = {
  64         &iio_dev_attr_dds.dev_attr.attr,
  65         NULL,
  66 };
  67
  68 static const struct attribute_group ad9850_attribute_group = {
  69         .attrs = ad9850_attributes,
  70 };
  71
  72 static const struct iio_info ad9850_info = {
  73         .attrs = &ad9850_attribute_group,
  74         .driver_module = THIS_MODULE,
  75 };
  76
  77 static int ad9850_probe(struct spi_device *spi)
  78 {
  79         struct ad9850_state *st;
  80         struct iio_dev *idev;
  81         int ret = 0;
  82
  83         idev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
  84         if (!idev)
  85                 return -ENOMEM;
  86         spi_set_drvdata(spi, idev);
  87         st = iio_priv(idev);
  88         mutex_init(&st->lock);
  89         st->sdev = spi;
  90
  91         idev->dev.parent = &spi->dev;
  92         idev->info = &ad9850_info;
  93         idev->modes = INDIO_DIRECT_MODE;
  94
  95         ret = iio_device_register(idev);
  96         if (ret)
  97                 return ret;
  98         spi->max_speed_hz = 2000000;
  99         spi->mode = SPI_MODE_3;
 100         spi->bits_per_word = 16;
 101         spi_setup(spi);
 102
 103         return 0;
 104 }
 105
 106 static int ad9850_remove(struct spi_device *spi)
 107 {
 108         iio_device_unregister(spi_get_drvdata(spi));
 109
 110         return 0;
 111 }
 112
 113 static struct spi_driver ad9850_driver = {
 114         .driver = {
 115                 .name = DRV_NAME,
 116                 .owner = THIS_MODULE,
 117         },
 118         .probe = ad9850_probe,
 119         .remove = ad9850_remove,
 120 };
 121 module_spi_driver(ad9850_driver);
 122
 123 MODULE_AUTHOR("Cliff Cai");
 124 MODULE_DESCRIPTION("Analog Devices ad9850 driver");
 125 MODULE_LICENSE("GPL v2");
 126 MODULE_ALIAS("spi:" DRV_NAME);