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yaml --- r: 289107 b: refs/heads/master c: 906ecf6 h: refs/heads/master i: 289105: 783b011 289103: 92433f6 v: v3
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Roland Stigge
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Greg Kroah-Hartman
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Feb 16, 2012
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refs/heads/master: 413db8c1c75a276c046ea476fee9364ca8df4d12 | ||
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/* | ||
* lpc32xx_adc.c - Support for ADC in LPC32XX | ||
* | ||
* 3-channel, 10-bit ADC | ||
* | ||
* Copyright (C) 2011, 2012 Roland Stigge <stigge@antcom.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; either version 2 of the License, or | ||
* (at your option) any later version. | ||
* | ||
* This program is distributed in the hope that it will be useful, | ||
* but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | ||
* GNU General Public License for more details. | ||
* | ||
* You should have received a copy of the GNU General Public License | ||
* along with this program; if not, write to the Free Software | ||
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | ||
*/ | ||
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#include <linux/module.h> | ||
#include <linux/platform_device.h> | ||
#include <linux/interrupt.h> | ||
#include <linux/device.h> | ||
#include <linux/kernel.h> | ||
#include <linux/slab.h> | ||
#include <linux/io.h> | ||
#include <linux/clk.h> | ||
#include <linux/err.h> | ||
#include <linux/completion.h> | ||
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#include "../iio.h" | ||
#include "../sysfs.h" | ||
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/* | ||
* LPC32XX registers definitions | ||
*/ | ||
#define LPC32XX_ADC_SELECT(x) ((x) + 0x04) | ||
#define LPC32XX_ADC_CTRL(x) ((x) + 0x08) | ||
#define LPC32XX_ADC_VALUE(x) ((x) + 0x48) | ||
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/* Bit definitions for LPC32XX_ADC_SELECT: */ | ||
#define AD_REFm 0x00000200 /* constant, always write this value! */ | ||
#define AD_REFp 0x00000080 /* constant, always write this value! */ | ||
#define AD_IN 0x00000010 /* multiple of this is the */ | ||
/* channel number: 0, 1, 2 */ | ||
#define AD_INTERNAL 0x00000004 /* constant, always write this value! */ | ||
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/* Bit definitions for LPC32XX_ADC_CTRL: */ | ||
#define AD_STROBE 0x00000002 | ||
#define AD_PDN_CTRL 0x00000004 | ||
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/* Bit definitions for LPC32XX_ADC_VALUE: */ | ||
#define ADC_VALUE_MASK 0x000003FF | ||
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#define MOD_NAME "lpc32xx-adc" | ||
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struct lpc32xx_adc_info { | ||
void __iomem *adc_base; | ||
struct clk *clk; | ||
struct completion completion; | ||
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u32 value; | ||
}; | ||
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static int lpc32xx_read_raw(struct iio_dev *indio_dev, | ||
struct iio_chan_spec const *chan, | ||
int *val, | ||
int *val2, | ||
long mask) | ||
{ | ||
struct lpc32xx_adc_info *info = iio_priv(indio_dev); | ||
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if (mask == 0) { | ||
mutex_lock(&indio_dev->mlock); | ||
clk_enable(info->clk); | ||
/* Measurement setup */ | ||
__raw_writel(AD_INTERNAL | (chan->address) | AD_REFp | AD_REFm, | ||
LPC32XX_ADC_SELECT(info->adc_base)); | ||
/* Trigger conversion */ | ||
__raw_writel(AD_PDN_CTRL | AD_STROBE, | ||
LPC32XX_ADC_CTRL(info->adc_base)); | ||
wait_for_completion(&info->completion); /* set by ISR */ | ||
clk_disable(info->clk); | ||
*val = info->value; | ||
mutex_unlock(&indio_dev->mlock); | ||
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return IIO_VAL_INT; | ||
} | ||
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return -EINVAL; | ||
} | ||
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static const struct iio_info lpc32xx_adc_iio_info = { | ||
.read_raw = &lpc32xx_read_raw, | ||
.driver_module = THIS_MODULE, | ||
}; | ||
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#define LPC32XX_ADC_CHANNEL(_index) { \ | ||
.type = IIO_VOLTAGE, \ | ||
.indexed = 1, \ | ||
.channel = _index, \ | ||
.address = AD_IN * _index, \ | ||
.scan_index = _index, \ | ||
} | ||
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static struct iio_chan_spec lpc32xx_adc_iio_channels[] = { | ||
LPC32XX_ADC_CHANNEL(0), | ||
LPC32XX_ADC_CHANNEL(1), | ||
LPC32XX_ADC_CHANNEL(2), | ||
}; | ||
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static irqreturn_t lpc32xx_adc_isr(int irq, void *dev_id) | ||
{ | ||
struct lpc32xx_adc_info *info = (struct lpc32xx_adc_info *) dev_id; | ||
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/* Read value and clear irq */ | ||
info->value = __raw_readl(LPC32XX_ADC_VALUE(info->adc_base)) & | ||
ADC_VALUE_MASK; | ||
complete(&info->completion); | ||
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return IRQ_HANDLED; | ||
} | ||
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static int __devinit lpc32xx_adc_probe(struct platform_device *pdev) | ||
{ | ||
struct lpc32xx_adc_info *info = NULL; | ||
struct resource *res; | ||
int retval = -ENODEV; | ||
struct iio_dev *iodev = NULL; | ||
int irq; | ||
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | ||
if (!res) { | ||
dev_err(&pdev->dev, "failed to get platform I/O memory\n"); | ||
retval = -EBUSY; | ||
goto errout1; | ||
} | ||
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iodev = iio_allocate_device(sizeof(struct lpc32xx_adc_info)); | ||
if (!iodev) { | ||
dev_err(&pdev->dev, "failed allocating iio device\n"); | ||
retval = -ENOMEM; | ||
goto errout1; | ||
} | ||
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info = iio_priv(iodev); | ||
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info->adc_base = ioremap(res->start, res->end - res->start + 1); | ||
if (!info->adc_base) { | ||
dev_err(&pdev->dev, "failed mapping memory\n"); | ||
retval = -EBUSY; | ||
goto errout2; | ||
} | ||
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info->clk = clk_get(&pdev->dev, NULL); | ||
if (IS_ERR(info->clk)) { | ||
dev_err(&pdev->dev, "failed getting clock\n"); | ||
goto errout3; | ||
} | ||
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irq = platform_get_irq(pdev, 0); | ||
if ((irq < 0) || (irq >= NR_IRQS)) { | ||
dev_err(&pdev->dev, "failed getting interrupt resource\n"); | ||
retval = -EINVAL; | ||
goto errout4; | ||
} | ||
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retval = request_irq(irq, lpc32xx_adc_isr, 0, MOD_NAME, info); | ||
if (retval < 0) { | ||
dev_err(&pdev->dev, "failed requesting interrupt\n"); | ||
goto errout4; | ||
} | ||
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platform_set_drvdata(pdev, iodev); | ||
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init_completion(&info->completion); | ||
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iodev->name = MOD_NAME; | ||
iodev->dev.parent = &pdev->dev; | ||
iodev->info = &lpc32xx_adc_iio_info; | ||
iodev->modes = INDIO_DIRECT_MODE; | ||
iodev->channels = lpc32xx_adc_iio_channels; | ||
iodev->num_channels = ARRAY_SIZE(lpc32xx_adc_iio_channels); | ||
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retval = iio_device_register(iodev); | ||
if (retval) | ||
goto errout5; | ||
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dev_info(&pdev->dev, "LPC32XX ADC driver loaded, IRQ %d\n", irq); | ||
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return 0; | ||
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errout5: | ||
free_irq(irq, iodev); | ||
errout4: | ||
clk_put(info->clk); | ||
errout3: | ||
iounmap(info->adc_base); | ||
errout2: | ||
iio_free_device(iodev); | ||
errout1: | ||
return retval; | ||
} | ||
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static int __devexit lpc32xx_adc_remove(struct platform_device *pdev) | ||
{ | ||
struct iio_dev *iodev = platform_get_drvdata(pdev); | ||
struct lpc32xx_adc_info *info = iio_priv(iodev); | ||
int irq = platform_get_irq(pdev, 0); | ||
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iio_device_unregister(iodev); | ||
free_irq(irq, iodev); | ||
platform_set_drvdata(pdev, NULL); | ||
clk_put(info->clk); | ||
iounmap(info->adc_base); | ||
iio_free_device(iodev); | ||
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return 0; | ||
} | ||
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static struct platform_driver lpc32xx_adc_driver = { | ||
.probe = lpc32xx_adc_probe, | ||
.remove = __devexit_p(lpc32xx_adc_remove), | ||
.driver = { | ||
.name = MOD_NAME, | ||
.owner = THIS_MODULE, | ||
}, | ||
}; | ||
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module_platform_driver(lpc32xx_adc_driver); | ||
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MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>"); | ||
MODULE_DESCRIPTION("LPC32XX ADC driver"); | ||
MODULE_LICENSE("GPL"); |