men_z188_adc.c
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/*
* MEN 16z188 Analog to Digial Converter
*
* Copyright (C) 2014 MEN Mikroelektronik GmbH (www.men.de)
* Author: Johannes Thumshirn <johannes.thumshirn@men.de>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; version 2 of the License.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mcb.h>
#include <linux/io.h>
#include <linux/iio/iio.h>
#define Z188_ADC_MAX_CHAN 8
#define Z188_ADC_GAIN 0x0700000
#define Z188_MODE_VOLTAGE BIT(27)
#define Z188_CFG_AUTO 0x1
#define Z188_CTRL_REG 0x40
#define ADC_DATA(x) (((x) >> 2) & 0x7ffffc)
#define ADC_OVR(x) ((x) & 0x1)
struct z188_adc {
struct resource *mem;
void __iomem *base;
};
#define Z188_ADC_CHANNEL(idx) { \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.channel = (idx), \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
}
static const struct iio_chan_spec z188_adc_iio_channels[] = {
Z188_ADC_CHANNEL(0),
Z188_ADC_CHANNEL(1),
Z188_ADC_CHANNEL(2),
Z188_ADC_CHANNEL(3),
Z188_ADC_CHANNEL(4),
Z188_ADC_CHANNEL(5),
Z188_ADC_CHANNEL(6),
Z188_ADC_CHANNEL(7),
};
static int z188_iio_read_raw(struct iio_dev *iio_dev,
struct iio_chan_spec const *chan,
int *val,
int *val2,
long info)
{
struct z188_adc *adc = iio_priv(iio_dev);
int ret;
u16 tmp;
switch (info) {
case IIO_CHAN_INFO_RAW:
tmp = readw(adc->base + chan->channel * 4);
if (ADC_OVR(tmp)) {
dev_info(&iio_dev->dev,
"Oversampling error on ADC channel %d\n",
chan->channel);
return -EIO;
}
*val = ADC_DATA(tmp);
ret = IIO_VAL_INT;
break;
default:
ret = -EINVAL;
break;
}
return ret;
}
static struct iio_info z188_adc_info = {
.read_raw = &z188_iio_read_raw,
.driver_module = THIS_MODULE,
};
static void men_z188_config_channels(void __iomem *addr)
{
int i;
u32 cfg;
u32 ctl;
ctl = readl(addr + Z188_CTRL_REG);
ctl |= Z188_CFG_AUTO;
writel(ctl, addr + Z188_CTRL_REG);
for (i = 0; i < Z188_ADC_MAX_CHAN; i++) {
cfg = readl(addr + i);
cfg &= ~Z188_ADC_GAIN;
cfg |= Z188_MODE_VOLTAGE;
writel(cfg, addr + i);
}
}
static int men_z188_probe(struct mcb_device *dev,
const struct mcb_device_id *id)
{
struct z188_adc *adc;
struct iio_dev *indio_dev;
struct resource *mem;
indio_dev = devm_iio_device_alloc(&dev->dev, sizeof(struct z188_adc));
if (!indio_dev)
return -ENOMEM;
adc = iio_priv(indio_dev);
indio_dev->name = "z188-adc";
indio_dev->dev.parent = &dev->dev;
indio_dev->info = &z188_adc_info;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = z188_adc_iio_channels;
indio_dev->num_channels = ARRAY_SIZE(z188_adc_iio_channels);
mem = mcb_request_mem(dev, "z188-adc");
if (IS_ERR(mem))
return PTR_ERR(mem);
adc->base = ioremap(mem->start, resource_size(mem));
if (adc->base == NULL)
goto err;
men_z188_config_channels(adc->base);
adc->mem = mem;
mcb_set_drvdata(dev, indio_dev);
return iio_device_register(indio_dev);
err:
mcb_release_mem(mem);
return -ENXIO;
}
static void men_z188_remove(struct mcb_device *dev)
{
struct iio_dev *indio_dev = mcb_get_drvdata(dev);
struct z188_adc *adc = iio_priv(indio_dev);
iio_device_unregister(indio_dev);
iounmap(adc->base);
mcb_release_mem(adc->mem);
}
static const struct mcb_device_id men_z188_ids[] = {
{ .device = 0xbc },
{ }
};
MODULE_DEVICE_TABLE(mcb, men_z188_ids);
static struct mcb_driver men_z188_driver = {
.driver = {
.name = "z188-adc",
.owner = THIS_MODULE,
},
.probe = men_z188_probe,
.remove = men_z188_remove,
.id_table = men_z188_ids,
};
module_mcb_driver(men_z188_driver);
MODULE_AUTHOR("Johannes Thumshirn <johannes.thumshirn@men.de>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("IIO ADC driver for MEN 16z188 ADC Core");
MODULE_ALIAS("mcb:16z188");