1/*
2 * MEN 16z188 Analog to Digial Converter
3 *
4 * Copyright (C) 2014 MEN Mikroelektronik GmbH (www.men.de)
5 * Author: Johannes Thumshirn <johannes.thumshirn@men.de>
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License as published by the Free
9 * Software Foundation; version 2 of the License.
10 */
11
12#include <linux/kernel.h>
13#include <linux/module.h>
14#include <linux/mcb.h>
15#include <linux/io.h>
16#include <linux/iio/iio.h>
17
18#define Z188_ADC_MAX_CHAN	8
19#define Z188_ADC_GAIN		0x0700000
20#define Z188_MODE_VOLTAGE	BIT(27)
21#define Z188_CFG_AUTO		0x1
22#define Z188_CTRL_REG		0x40
23
24#define ADC_DATA(x) (((x) >> 2) & 0x7ffffc)
25#define ADC_OVR(x) ((x) & 0x1)
26
27struct z188_adc {
28	struct resource *mem;
29	void __iomem *base;
30};
31
32#define Z188_ADC_CHANNEL(idx) {					\
33		.type = IIO_VOLTAGE,				\
34		.indexed = 1,					\
35		.channel = (idx),				\
36		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
37}
38
39static const struct iio_chan_spec z188_adc_iio_channels[] = {
40	Z188_ADC_CHANNEL(0),
41	Z188_ADC_CHANNEL(1),
42	Z188_ADC_CHANNEL(2),
43	Z188_ADC_CHANNEL(3),
44	Z188_ADC_CHANNEL(4),
45	Z188_ADC_CHANNEL(5),
46	Z188_ADC_CHANNEL(6),
47	Z188_ADC_CHANNEL(7),
48};
49
50static int z188_iio_read_raw(struct iio_dev *iio_dev,
51			struct iio_chan_spec const *chan,
52			int *val,
53			int *val2,
54			long info)
55{
56	struct z188_adc *adc = iio_priv(iio_dev);
57	int ret;
58	u16 tmp;
59
60	switch (info) {
61	case IIO_CHAN_INFO_RAW:
62		tmp = readw(adc->base + chan->channel * 4);
63
64		if (ADC_OVR(tmp)) {
65			dev_info(&iio_dev->dev,
66				"Oversampling error on ADC channel %d\n",
67				chan->channel);
68			return -EIO;
69		}
70		*val = ADC_DATA(tmp);
71		ret = IIO_VAL_INT;
72		break;
73	default:
74		ret = -EINVAL;
75		break;
76	}
77
78	return ret;
79}
80
81static struct iio_info z188_adc_info = {
82	.read_raw = &z188_iio_read_raw,
83	.driver_module = THIS_MODULE,
84};
85
86static void men_z188_config_channels(void __iomem *addr)
87{
88	int i;
89	u32 cfg;
90	u32 ctl;
91
92	ctl = readl(addr + Z188_CTRL_REG);
93	ctl |= Z188_CFG_AUTO;
94	writel(ctl, addr + Z188_CTRL_REG);
95
96	for (i = 0; i < Z188_ADC_MAX_CHAN; i++) {
97		cfg = readl(addr + i);
98		cfg &= ~Z188_ADC_GAIN;
99		cfg |= Z188_MODE_VOLTAGE;
100		writel(cfg, addr + i);
101	}
102}
103
104static int men_z188_probe(struct mcb_device *dev,
105			const struct mcb_device_id *id)
106{
107	struct z188_adc *adc;
108	struct iio_dev *indio_dev;
109	struct resource *mem;
110
111	indio_dev = devm_iio_device_alloc(&dev->dev, sizeof(struct z188_adc));
112	if (!indio_dev)
113		return -ENOMEM;
114
115	adc = iio_priv(indio_dev);
116	indio_dev->name = "z188-adc";
117	indio_dev->dev.parent = &dev->dev;
118	indio_dev->info = &z188_adc_info;
119	indio_dev->modes = INDIO_DIRECT_MODE;
120	indio_dev->channels = z188_adc_iio_channels;
121	indio_dev->num_channels = ARRAY_SIZE(z188_adc_iio_channels);
122
123	mem = mcb_request_mem(dev, "z188-adc");
124	if (IS_ERR(mem))
125		return PTR_ERR(mem);
126
127	adc->base = ioremap(mem->start, resource_size(mem));
128	if (adc->base == NULL)
129		goto err;
130
131	men_z188_config_channels(adc->base);
132
133	adc->mem = mem;
134	mcb_set_drvdata(dev, indio_dev);
135
136	return iio_device_register(indio_dev);
137
138err:
139	mcb_release_mem(mem);
140	return -ENXIO;
141}
142
143static void men_z188_remove(struct mcb_device *dev)
144{
145	struct iio_dev *indio_dev  = mcb_get_drvdata(dev);
146	struct z188_adc *adc = iio_priv(indio_dev);
147
148	iio_device_unregister(indio_dev);
149	iounmap(adc->base);
150	mcb_release_mem(adc->mem);
151}
152
153static const struct mcb_device_id men_z188_ids[] = {
154	{ .device = 0xbc },
155	{ }
156};
157MODULE_DEVICE_TABLE(mcb, men_z188_ids);
158
159static struct mcb_driver men_z188_driver = {
160	.driver = {
161		.name = "z188-adc",
162		.owner = THIS_MODULE,
163	},
164	.probe = men_z188_probe,
165	.remove = men_z188_remove,
166	.id_table = men_z188_ids,
167};
168module_mcb_driver(men_z188_driver);
169
170MODULE_AUTHOR("Johannes Thumshirn <johannes.thumshirn@men.de>");
171MODULE_LICENSE("GPL");
172MODULE_DESCRIPTION("IIO ADC driver for MEN 16z188 ADC Core");
173MODULE_ALIAS("mcb:16z188");
174