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
25struct vprbrd_adc_msg {
26	u8 cmd;
27	u8 chan;
28	u8 val;
29} __packed;
30
31struct 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
42static 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
49static 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	}
99error:
100	return error;
101}
102
103static const struct iio_info vprbrd_adc_iio_info = {
104	.read_raw = &vprbrd_iio_read_raw,
105};
106
107static 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
138static struct platform_driver vprbrd_adc_driver = {
139	.driver = {
140		.name	= "viperboard-adc",
141	},
142	.probe		= vprbrd_adc_probe,
143};
144
145module_platform_driver(vprbrd_adc_driver);
146
147MODULE_AUTHOR("Lars Poeschel <poeschel@lemonage.de>");
148MODULE_DESCRIPTION("IIO ADC driver for Nano River Techs Viperboard");
149MODULE_LICENSE("GPL");
150MODULE_ALIAS("platform:viperboard-adc");
151