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
30struct vprbrd_adc_msg {
31	u8 cmd;
32	u8 chan;
33	u8 val;
34} __packed;
35
36struct 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
47static 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
54static 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	}
104error:
105	return error;
106}
107
108static const struct iio_info vprbrd_adc_iio_info = {
109	.read_raw = &vprbrd_iio_read_raw,
110	.driver_module = THIS_MODULE,
111};
112
113static 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
145static struct platform_driver vprbrd_adc_driver = {
146	.driver = {
147		.name	= "viperboard-adc",
148	},
149	.probe		= vprbrd_adc_probe,
150};
151
152module_platform_driver(vprbrd_adc_driver);
153
154MODULE_AUTHOR("Lars Poeschel <poeschel@lemonage.de>");
155MODULE_DESCRIPTION("IIO ADC driver for Nano River Techs Viperboard");
156MODULE_LICENSE("GPL");
157MODULE_ALIAS("platform:viperboard-adc");
158