xref: /openbmc/linux/drivers/iio/adc/men_z188_adc.c (revision e19480dd)
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 
24 struct 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 
36 static 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 
z188_iio_read_raw(struct iio_dev * iio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long info)47 static 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 
78 static const struct iio_info z188_adc_info = {
79 	.read_raw = &z188_iio_read_raw,
80 };
81 
men_z188_config_channels(void __iomem * addr)82 static 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 
men_z188_probe(struct mcb_device * dev,const struct mcb_device_id * id)100 static 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 
138 err_unmap:
139 	iounmap(adc->base);
140 err:
141 	mcb_release_mem(mem);
142 	return -ENXIO;
143 }
144 
men_z188_remove(struct mcb_device * dev)145 static 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 
155 static const struct mcb_device_id men_z188_ids[] = {
156 	{ .device = 0xbc },
157 	{ }
158 };
159 MODULE_DEVICE_TABLE(mcb, men_z188_ids);
160 
161 static 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 };
169 module_mcb_driver(men_z188_driver);
170 
171 MODULE_AUTHOR("Johannes Thumshirn <johannes.thumshirn@men.de>");
172 MODULE_LICENSE("GPL");
173 MODULE_DESCRIPTION("IIO ADC driver for MEN 16z188 ADC Core");
174 MODULE_ALIAS("mcb:16z188");
175 MODULE_IMPORT_NS(MCB);
176