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 }
  46
  47 static struct iio_chan_spec const vprbrd_adc_iio_channels[] = {
  48         VPRBRD_ADC_CHANNEL(0),
  49         VPRBRD_ADC_CHANNEL(1),
  50         VPRBRD_ADC_CHANNEL(2),
  51         VPRBRD_ADC_CHANNEL(3),
  52 };
  53
  54 static int vprbrd_iio_read_raw(struct iio_dev *iio_dev,
  55                                 struct iio_chan_spec const *chan,
  56                                 int *val,
  57                                 int *val2,
  58                                 long info)
  59 {
  60         int ret, error = 0;
  61         struct vprbrd_adc *adc = iio_priv(iio_dev);
  62         struct vprbrd *vb = adc->vb;
  63         struct vprbrd_adc_msg *admsg = (struct vprbrd_adc_msg *)vb->buf;
  64
  65         switch (info) {
  66         case IIO_CHAN_INFO_RAW:
  67                 mutex_lock(&vb->lock);
  68
  69                 admsg->cmd = VPRBRD_ADC_CMD_GET;
  70                 admsg->chan = chan->channel;
  71                 admsg->val = 0x00;
  72
  73                 ret = usb_control_msg(vb->usb_dev,
  74                         usb_sndctrlpipe(vb->usb_dev, 0), VPRBRD_USB_REQUEST_ADC,
  75                         VPRBRD_USB_TYPE_OUT, 0x0000, 0x0000, admsg,
  76                         sizeof(struct vprbrd_adc_msg), VPRBRD_USB_TIMEOUT_MS);
  77                 if (ret != sizeof(struct vprbrd_adc_msg)) {
  78                         dev_err(&iio_dev->dev, "usb send error on adc read\n");
  79                         error = -EREMOTEIO;
  80                 }
  81
  82                 ret = usb_control_msg(vb->usb_dev,
  83                         usb_rcvctrlpipe(vb->usb_dev, 0), VPRBRD_USB_REQUEST_ADC,
  84                         VPRBRD_USB_TYPE_IN, 0x0000, 0x0000, admsg,
  85                         sizeof(struct vprbrd_adc_msg), VPRBRD_USB_TIMEOUT_MS);
  86
  87                 *val = admsg->val;
  88
  89                 mutex_unlock(&vb->lock);
  90
  91                 if (ret != sizeof(struct vprbrd_adc_msg)) {
  92                         dev_err(&iio_dev->dev, "usb recv error on adc read\n");
  93                         error = -EREMOTEIO;
  94                 }
  95
  96                 if (error)
  97                         goto error;
  98
  99                 return IIO_VAL_INT;
 100         default:
 101                 error = -EINVAL;
 102                 break;
 103         }
 104 error:
 105         return error;
 106 }
 107
 108 static const struct iio_info vprbrd_adc_iio_info = {
 109         .read_raw = &vprbrd_iio_read_raw,
 110         .driver_module = THIS_MODULE,
 111 };
 112
 113 static int vprbrd_adc_probe(struct platform_device *pdev)
 114 {
 115         struct vprbrd *vb = dev_get_drvdata(pdev->dev.parent);
 116         struct vprbrd_adc *adc;
 117         struct iio_dev *indio_dev;
 118         int ret;
 119
 120         /* registering iio */
 121         indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc));
 122         if (!indio_dev) {
 123                 dev_err(&pdev->dev, "failed allocating iio device\n");
 124                 return -ENOMEM;
 125         }
 126
 127         adc = iio_priv(indio_dev);
 128         adc->vb = vb;
 129         indio_dev->name = "viperboard adc";
 130         indio_dev->dev.parent = &pdev->dev;
 131         indio_dev->info = &vprbrd_adc_iio_info;
 132         indio_dev->modes = INDIO_DIRECT_MODE;
 133         indio_dev->channels = vprbrd_adc_iio_channels;
 134         indio_dev->num_channels = ARRAY_SIZE(vprbrd_adc_iio_channels);
 135
 136         ret = devm_iio_device_register(&pdev->dev, indio_dev);
 137         if (ret) {
 138                 dev_err(&pdev->dev, "could not register iio (adc)");
 139                 return ret;
 140         }
 141
 142         return 0;
 143 }
 144
 145 static struct platform_driver vprbrd_adc_driver = {
 146         .driver = {
 147                 .name   = "viperboard-adc",
 148         },
 149         .probe          = vprbrd_adc_probe,
 150 };
 151
 152 module_platform_driver(vprbrd_adc_driver);
 153
 154 MODULE_AUTHOR("Lars Poeschel <poeschel@lemonage.de>");
 155 MODULE_DESCRIPTION("IIO ADC driver for Nano River Techs Viperboard");
 156 MODULE_LICENSE("GPL");
 157 MODULE_ALIAS("platform:viperboard-adc");