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
vprbrd_iio_read_raw(struct iio_dev * iio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long info)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 mutex_unlock(&vb->lock);
74 error = -EREMOTEIO;
75 dev_err(&iio_dev->dev, "usb send error on adc read\n");
76 goto error;
77 }
78
79 ret = usb_control_msg(vb->usb_dev,
80 usb_rcvctrlpipe(vb->usb_dev, 0), VPRBRD_USB_REQUEST_ADC,
81 VPRBRD_USB_TYPE_IN, 0x0000, 0x0000, admsg,
82 sizeof(struct vprbrd_adc_msg), VPRBRD_USB_TIMEOUT_MS);
83
84 *val = admsg->val;
85
86 mutex_unlock(&vb->lock);
87
88 if (ret != sizeof(struct vprbrd_adc_msg)) {
89 dev_err(&iio_dev->dev, "usb recv error on adc read\n");
90 error = -EREMOTEIO;
91 }
92
93 if (error)
94 goto error;
95
96 return IIO_VAL_INT;
97 default:
98 error = -EINVAL;
99 break;
100 }
101 error:
102 return error;
103 }
104
105 static const struct iio_info vprbrd_adc_iio_info = {
106 .read_raw = &vprbrd_iio_read_raw,
107 };
108
vprbrd_adc_probe(struct platform_device * pdev)109 static int vprbrd_adc_probe(struct platform_device *pdev)
110 {
111 struct vprbrd *vb = dev_get_drvdata(pdev->dev.parent);
112 struct vprbrd_adc *adc;
113 struct iio_dev *indio_dev;
114 int ret;
115
116 /* registering iio */
117 indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc));
118 if (!indio_dev)
119 return -ENOMEM;
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");
151