drivers/iio/adc/viperboard_adc.c

   1 /*
   2  *  Nano River Technologies viperboard IIO ADC driver
   3  *
   4  *  (C) 2012 by Lemonage GmbH
   5  *  Author: Lars Poeschel <poeschel@lemonage.de>
   6  *  All rights reserved.
   7  *
   8  *  This program is free software; you can redistribute  it and/or modify it
   9  *  under  the terms of  the GNU General  Public License as published by the
  10  *  Free Software Foundation;  either version 2 of the  License, or (at your
  11  *  option) any later version.
  12  *
  13  */
  14
  15 #include <linux/kernel.h>
  16 #include <linux/errno.h>
  17 #include <linux/module.h>
  18 #include <linux/slab.h>
  19 #include <linux/types.h>
  20 #include <linux/mutex.h>
  21 #include <linux/platform_device.h>
  22
  23 #include <linux/usb.h>
  24 #include <linux/iio/iio.h>
  25
  26 #include <linux/mfd/viperboard.h>
  27
  28 #define VPRBRD_ADC_CMD_GET              0x00
  29
  30 struct vprbrd_adc_msg {
  31         u8 cmd;
  32         u8 chan;
  33         u8 val;
  34 } __packed;
  35
  36 struct vprbrd_adc {
  37         struct vprbrd *vb;
  38 };
  39
  40 #define VPRBRD_ADC_CHANNEL(_index) {                    \
  41         .type = IIO_VOLTAGE,                            \
  42         .indexed = 1,                                   \
  43         .channel = _index,                              \
  44         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
  45         .scan_index = _index,                           \
  46         .scan_type = {                                  \
  47                 .sign = 'u',                            \
  48                 .realbits = 8,                          \
  49                 .storagebits = 8,                       \
  50         },                                              \
  51 }
  52
  53 static struct iio_chan_spec const vprbrd_adc_iio_channels[] = {
  54         VPRBRD_ADC_CHANNEL(0),
  55         VPRBRD_ADC_CHANNEL(1),
  56         VPRBRD_ADC_CHANNEL(2),
  57         VPRBRD_ADC_CHANNEL(3),
  58 };
  59
  60 static int vprbrd_iio_read_raw(struct iio_dev *iio_dev,
  61                                 struct iio_chan_spec const *chan,
  62                                 int *val,
  63                                 int *val2,
  64                                 long info)
  65 {
  66         int ret, error = 0;
  67         struct vprbrd_adc *adc = iio_priv(iio_dev);
  68         struct vprbrd *vb = adc->vb;
  69         struct vprbrd_adc_msg *admsg = (struct vprbrd_adc_msg *)vb->buf;
  70
  71         switch (info) {
  72         case IIO_CHAN_INFO_RAW:
  73                 mutex_lock(&vb->lock);
  74
  75                 admsg->cmd = VPRBRD_ADC_CMD_GET;
  76                 admsg->chan = chan->scan_index;
  77                 admsg->val = 0x00;
  78
  79                 ret = usb_control_msg(vb->usb_dev,
  80                         usb_sndctrlpipe(vb->usb_dev, 0), VPRBRD_USB_REQUEST_ADC,
  81                         VPRBRD_USB_TYPE_OUT, 0x0000, 0x0000, admsg,
  82                         sizeof(struct vprbrd_adc_msg), VPRBRD_USB_TIMEOUT_MS);
  83                 if (ret != sizeof(struct vprbrd_adc_msg)) {
  84                         dev_err(&iio_dev->dev, "usb send error on adc read\n");
  85                         error = -EREMOTEIO;
  86                 }
  87
  88                 ret = usb_control_msg(vb->usb_dev,
  89                         usb_rcvctrlpipe(vb->usb_dev, 0), VPRBRD_USB_REQUEST_ADC,
  90                         VPRBRD_USB_TYPE_IN, 0x0000, 0x0000, admsg,
  91                         sizeof(struct vprbrd_adc_msg), VPRBRD_USB_TIMEOUT_MS);
  92
  93                 *val = admsg->val;
  94
  95                 mutex_unlock(&vb->lock);
  96
  97                 if (ret != sizeof(struct vprbrd_adc_msg)) {
  98                         dev_err(&iio_dev->dev, "usb recv error on adc read\n");
  99                         error = -EREMOTEIO;
 100                 }
 101
 102                 if (error)
 103                         goto error;
 104
 105                 return IIO_VAL_INT;
 106         default:
 107                 error = -EINVAL;
 108                 break;
 109         }
 110 error:
 111         return error;
 112 }
 113
 114 static const struct iio_info vprbrd_adc_iio_info = {
 115         .read_raw = &vprbrd_iio_read_raw,
 116         .driver_module = THIS_MODULE,
 117 };
 118
 119 static int vprbrd_adc_probe(struct platform_device *pdev)
 120 {
 121         struct vprbrd *vb = dev_get_drvdata(pdev->dev.parent);
 122         struct vprbrd_adc *adc;
 123         struct iio_dev *indio_dev;
 124         int ret;
 125
 126         /* registering iio */
 127         indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc));
 128         if (!indio_dev) {
 129                 dev_err(&pdev->dev, "failed allocating iio device\n");
 130                 return -ENOMEM;
 131         }
 132
 133         adc = iio_priv(indio_dev);
 134         adc->vb = vb;
 135         indio_dev->name = "viperboard adc";
 136         indio_dev->dev.parent = &pdev->dev;
 137         indio_dev->info = &vprbrd_adc_iio_info;
 138         indio_dev->modes = INDIO_DIRECT_MODE;
 139         indio_dev->channels = vprbrd_adc_iio_channels;
 140         indio_dev->num_channels = ARRAY_SIZE(vprbrd_adc_iio_channels);
 141
 142         ret = iio_device_register(indio_dev);
 143         if (ret) {
 144                 dev_err(&pdev->dev, "could not register iio (adc)");
 145                 return ret;
 146         }
 147
 148         platform_set_drvdata(pdev, indio_dev);
 149
 150         return 0;
 151 }
 152
 153 static int vprbrd_adc_remove(struct platform_device *pdev)
 154 {
 155         struct iio_dev *indio_dev = platform_get_drvdata(pdev);
 156
 157         iio_device_unregister(indio_dev);
 158
 159         return 0;
 160 }
 161
 162 static struct platform_driver vprbrd_adc_driver = {
 163         .driver = {
 164                 .name   = "viperboard-adc",
 165                 .owner  = THIS_MODULE,
 166         },
 167         .probe          = vprbrd_adc_probe,
 168         .remove         = vprbrd_adc_remove,
 169 };
 170
 171 module_platform_driver(vprbrd_adc_driver);
 172
 173 MODULE_AUTHOR("Lars Poeschel <poeschel@lemonage.de>");
 174 MODULE_DESCRIPTION("IIO ADC driver for Nano River Techs Viperboard");
 175 MODULE_LICENSE("GPL");
 176 MODULE_ALIAS("platform:viperboard-adc");