drivers/iio/adc/viperboard_adc.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  Nano River Technologies viperboard IIO ADC driver
   4  *
   5  *  (C) 2012 by Lemonage GmbH
   6  *  Author: Lars Poeschel <poeschel@lemonage.de>
   7  *  All rights reserved.
   8  */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/errno.h>
  12 #include <linux/module.h>
  13 #include <linux/slab.h>
  14 #include <linux/types.h>
  15 #include <linux/mutex.h>
  16 #include <linux/platform_device.h>
  17
  18 #include <linux/usb.h>
  19 #include <linux/iio/iio.h>
  20
  21 #include <linux/mfd/viperboard.h>
  22
  23 #define VPRBRD_ADC_CMD_GET              0x00
  24
  25 struct vprbrd_adc_msg {
  26         u8 cmd;
  27         u8 chan;
  28         u8 val;
  29 } __packed;
  30
  31 struct vprbrd_adc {
  32         struct vprbrd *vb;
  33 };
  34
  35 #define VPRBRD_ADC_CHANNEL(_index) {                    \
  36         .type = IIO_VOLTAGE,                            \
  37         .indexed = 1,                                   \
  38         .channel = _index,                              \
  39         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
  40 }
  41
  42 static struct iio_chan_spec const vprbrd_adc_iio_channels[] = {
  43         VPRBRD_ADC_CHANNEL(0),
  44         VPRBRD_ADC_CHANNEL(1),
  45         VPRBRD_ADC_CHANNEL(2),
  46         VPRBRD_ADC_CHANNEL(3),
  47 };
  48
  49 static int vprbrd_iio_read_raw(struct iio_dev *iio_dev,
  50                                 struct iio_chan_spec const *chan,
  51                                 int *val,
  52                                 int *val2,
  53                                 long info)
  54 {
  55         int ret, error = 0;
  56         struct vprbrd_adc *adc = iio_priv(iio_dev);
  57         struct vprbrd *vb = adc->vb;
  58         struct vprbrd_adc_msg *admsg = (struct vprbrd_adc_msg *)vb->buf;
  59
  60         switch (info) {
  61         case IIO_CHAN_INFO_RAW:
  62                 mutex_lock(&vb->lock);
  63
  64                 admsg->cmd = VPRBRD_ADC_CMD_GET;
  65                 admsg->chan = chan->channel;
  66                 admsg->val = 0x00;
  67
  68                 ret = usb_control_msg(vb->usb_dev,
  69                         usb_sndctrlpipe(vb->usb_dev, 0), VPRBRD_USB_REQUEST_ADC,
  70                         VPRBRD_USB_TYPE_OUT, 0x0000, 0x0000, admsg,
  71                         sizeof(struct vprbrd_adc_msg), VPRBRD_USB_TIMEOUT_MS);
  72                 if (ret != sizeof(struct vprbrd_adc_msg)) {
  73                         dev_err(&iio_dev->dev, "usb send error on adc read\n");
  74                         error = -EREMOTEIO;
  75                 }
  76
  77                 ret = usb_control_msg(vb->usb_dev,
  78                         usb_rcvctrlpipe(vb->usb_dev, 0), VPRBRD_USB_REQUEST_ADC,
  79                         VPRBRD_USB_TYPE_IN, 0x0000, 0x0000, admsg,
  80                         sizeof(struct vprbrd_adc_msg), VPRBRD_USB_TIMEOUT_MS);
  81
  82                 *val = admsg->val;
  83
  84                 mutex_unlock(&vb->lock);
  85
  86                 if (ret != sizeof(struct vprbrd_adc_msg)) {
  87                         dev_err(&iio_dev->dev, "usb recv error on adc read\n");
  88                         error = -EREMOTEIO;
  89                 }
  90
  91                 if (error)
  92                         goto error;
  93
  94                 return IIO_VAL_INT;
  95         default:
  96                 error = -EINVAL;
  97                 break;
  98         }
  99 error:
 100         return error;
 101 }
 102
 103 static const struct iio_info vprbrd_adc_iio_info = {
 104         .read_raw = &vprbrd_iio_read_raw,
 105 };
 106
 107 static int vprbrd_adc_probe(struct platform_device *pdev)
 108 {
 109         struct vprbrd *vb = dev_get_drvdata(pdev->dev.parent);
 110         struct vprbrd_adc *adc;
 111         struct iio_dev *indio_dev;
 112         int ret;
 113
 114         /* registering iio */
 115         indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc));
 116         if (!indio_dev) {
 117                 dev_err(&pdev->dev, "failed allocating iio device\n");
 118                 return -ENOMEM;
 119         }
 120
 121         adc = iio_priv(indio_dev);
 122         adc->vb = vb;
 123         indio_dev->name = "viperboard adc";
 124         indio_dev->info = &vprbrd_adc_iio_info;
 125         indio_dev->modes = INDIO_DIRECT_MODE;
 126         indio_dev->channels = vprbrd_adc_iio_channels;
 127         indio_dev->num_channels = ARRAY_SIZE(vprbrd_adc_iio_channels);
 128
 129         ret = devm_iio_device_register(&pdev->dev, indio_dev);
 130         if (ret) {
 131                 dev_err(&pdev->dev, "could not register iio (adc)");
 132                 return ret;
 133         }
 134
 135         return 0;
 136 }
 137
 138 static struct platform_driver vprbrd_adc_driver = {
 139         .driver = {
 140                 .name   = "viperboard-adc",
 141         },
 142         .probe          = vprbrd_adc_probe,
 143 };
 144
 145 module_platform_driver(vprbrd_adc_driver);
 146
 147 MODULE_AUTHOR("Lars Poeschel <poeschel@lemonage.de>");
 148 MODULE_DESCRIPTION("IIO ADC driver for Nano River Techs Viperboard");
 149 MODULE_LICENSE("GPL");
 150 MODULE_ALIAS("platform:viperboard-adc");