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