1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * MEN 16z188 Analog to Digial Converter
4 *
5 * Copyright (C) 2014 MEN Mikroelektronik GmbH (www.men.de)
6 * Author: Johannes Thumshirn <johannes.thumshirn@men.de>
7 */
8
9#include <linux/kernel.h>
10#include <linux/module.h>
11#include <linux/mcb.h>
12#include <linux/io.h>
13#include <linux/iio/iio.h>
14
15#define Z188_ADC_MAX_CHAN	8
16#define Z188_ADC_GAIN		0x0700000
17#define Z188_MODE_VOLTAGE	BIT(27)
18#define Z188_CFG_AUTO		0x1
19#define Z188_CTRL_REG		0x40
20
21#define ADC_DATA(x) (((x) >> 2) & 0x7ffffc)
22#define ADC_OVR(x) ((x) & 0x1)
23
24struct z188_adc {
25	struct resource *mem;
26	void __iomem *base;
27};
28
29#define Z188_ADC_CHANNEL(idx) {					\
30		.type = IIO_VOLTAGE,				\
31		.indexed = 1,					\
32		.channel = (idx),				\
33		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
34}
35
36static const struct iio_chan_spec z188_adc_iio_channels[] = {
37	Z188_ADC_CHANNEL(0),
38	Z188_ADC_CHANNEL(1),
39	Z188_ADC_CHANNEL(2),
40	Z188_ADC_CHANNEL(3),
41	Z188_ADC_CHANNEL(4),
42	Z188_ADC_CHANNEL(5),
43	Z188_ADC_CHANNEL(6),
44	Z188_ADC_CHANNEL(7),
45};
46
47static int z188_iio_read_raw(struct iio_dev *iio_dev,
48			struct iio_chan_spec const *chan,
49			int *val,
50			int *val2,
51			long info)
52{
53	struct z188_adc *adc = iio_priv(iio_dev);
54	int ret;
55	u16 tmp;
56
57	switch (info) {
58	case IIO_CHAN_INFO_RAW:
59		tmp = readw(adc->base + chan->channel * 4);
60
61		if (ADC_OVR(tmp)) {
62			dev_info(&iio_dev->dev,
63				"Oversampling error on ADC channel %d\n",
64				chan->channel);
65			return -EIO;
66		}
67		*val = ADC_DATA(tmp);
68		ret = IIO_VAL_INT;
69		break;
70	default:
71		ret = -EINVAL;
72		break;
73	}
74
75	return ret;
76}
77
78static const struct iio_info z188_adc_info = {
79	.read_raw = &z188_iio_read_raw,
80};
81
82static void men_z188_config_channels(void __iomem *addr)
83{
84	int i;
85	u32 cfg;
86	u32 ctl;
87
88	ctl = readl(addr + Z188_CTRL_REG);
89	ctl |= Z188_CFG_AUTO;
90	writel(ctl, addr + Z188_CTRL_REG);
91
92	for (i = 0; i < Z188_ADC_MAX_CHAN; i++) {
93		cfg = readl(addr + i);
94		cfg &= ~Z188_ADC_GAIN;
95		cfg |= Z188_MODE_VOLTAGE;
96		writel(cfg, addr + i);
97	}
98}
99
100static int men_z188_probe(struct mcb_device *dev,
101			const struct mcb_device_id *id)
102{
103	struct z188_adc *adc;
104	struct iio_dev *indio_dev;
105	struct resource *mem;
106	int ret;
107
108	indio_dev = devm_iio_device_alloc(&dev->dev, sizeof(struct z188_adc));
109	if (!indio_dev)
110		return -ENOMEM;
111
112	adc = iio_priv(indio_dev);
113	indio_dev->name = "z188-adc";
114	indio_dev->info = &z188_adc_info;
115	indio_dev->modes = INDIO_DIRECT_MODE;
116	indio_dev->channels = z188_adc_iio_channels;
117	indio_dev->num_channels = ARRAY_SIZE(z188_adc_iio_channels);
118
119	mem = mcb_request_mem(dev, "z188-adc");
120	if (IS_ERR(mem))
121		return PTR_ERR(mem);
122
123	adc->base = ioremap(mem->start, resource_size(mem));
124	if (adc->base == NULL)
125		goto err;
126
127	men_z188_config_channels(adc->base);
128
129	adc->mem = mem;
130	mcb_set_drvdata(dev, indio_dev);
131
132	ret = iio_device_register(indio_dev);
133	if (ret)
134		goto err_unmap;
135
136	return 0;
137
138err_unmap:
139	iounmap(adc->base);
140err:
141	mcb_release_mem(mem);
142	return -ENXIO;
143}
144
145static void men_z188_remove(struct mcb_device *dev)
146{
147	struct iio_dev *indio_dev  = mcb_get_drvdata(dev);
148	struct z188_adc *adc = iio_priv(indio_dev);
149
150	iio_device_unregister(indio_dev);
151	iounmap(adc->base);
152	mcb_release_mem(adc->mem);
153}
154
155static const struct mcb_device_id men_z188_ids[] = {
156	{ .device = 0xbc },
157	{ }
158};
159MODULE_DEVICE_TABLE(mcb, men_z188_ids);
160
161static struct mcb_driver men_z188_driver = {
162	.driver = {
163		.name = "z188-adc",
164	},
165	.probe = men_z188_probe,
166	.remove = men_z188_remove,
167	.id_table = men_z188_ids,
168};
169module_mcb_driver(men_z188_driver);
170
171MODULE_AUTHOR("Johannes Thumshirn <johannes.thumshirn@men.de>");
172MODULE_LICENSE("GPL");
173MODULE_DESCRIPTION("IIO ADC driver for MEN 16z188 ADC Core");
174MODULE_ALIAS("mcb:16z188");
175MODULE_IMPORT_NS(MCB);
176