staging: iio: LPC32xx: ADC driver (906ecf69) · Commits · e / devices / android_kernel_fairphone_FP3

drivers/staging/iio/adc/Kconfig

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Original line number	Diff line number	Diff line
		@@ -193,4 +193,13 @@ config MAX1363_RING_BUFFER
		Say yes here to include ring buffer support in the MAX1363
		ADC driver.

		config LPC32XX_ADC
		tristate "NXP LPC32XX ADC"
		depends on ARCH_LPC32XX && !TOUCHSCREEN_LPC32XX
		help
		Say yes here to build support for the integrated ADC inside the
		LPC32XX SoC. Note that this feature uses the same hardware as the
		touchscreen driver, so you can only select one of the two drivers
		(lpc32xx_adc or lpc32xx_ts). Provides direct access via sysfs.

		endmenu

drivers/staging/iio/adc/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -37,3 +37,4 @@ obj-$(CONFIG_AD7192) += ad7192.o
		obj-$(CONFIG_ADT7310) += adt7310.o
		obj-$(CONFIG_ADT7410) += adt7410.o
		obj-$(CONFIG_AD7280) += ad7280a.o
		obj-$(CONFIG_LPC32XX_ADC) += lpc32xx_adc.o

drivers/staging/iio/adc/lpc32xx_adc.c

0 → 100644

+237 −0

Original line number	Diff line number	Diff line
		/*
		* 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.
		*/

		#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>

		#include "../iio.h"
		#include "../sysfs.h"

		/*
		* LPC32XX registers definitions
		*/
		#define LPC32XX_ADC_SELECT(x) ((x) + 0x04)
		#define LPC32XX_ADC_CTRL(x) ((x) + 0x08)
		#define LPC32XX_ADC_VALUE(x) ((x) + 0x48)

		/* 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! */

		/* Bit definitions for LPC32XX_ADC_CTRL: */
		#define AD_STROBE 0x00000002
		#define AD_PDN_CTRL 0x00000004

		/* Bit definitions for LPC32XX_ADC_VALUE: */
		#define ADC_VALUE_MASK 0x000003FF

		#define MOD_NAME "lpc32xx-adc"

		struct lpc32xx_adc_info {
		void __iomem *adc_base;
		struct clk *clk;
		struct completion completion;

		u32 value;
		};

		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);

		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);

		return IIO_VAL_INT;
		}

		return -EINVAL;
		}

		static const struct iio_info lpc32xx_adc_iio_info = {
		.read_raw = &lpc32xx_read_raw,
		.driver_module = THIS_MODULE,
		};

		#define LPC32XX_ADC_CHANNEL(_index) { \
		.type = IIO_VOLTAGE, \
		.indexed = 1, \
		.channel = _index, \
		.address = AD_IN * _index, \
		.scan_index = _index, \
		}

		static struct iio_chan_spec lpc32xx_adc_iio_channels[] = {
		LPC32XX_ADC_CHANNEL(0),
		LPC32XX_ADC_CHANNEL(1),
		LPC32XX_ADC_CHANNEL(2),
		};

		static irqreturn_t lpc32xx_adc_isr(int irq, void *dev_id)
		{
		struct lpc32xx_adc_info info = (struct lpc32xx_adc_info ) dev_id;

		/* Read value and clear irq */
		info->value = __raw_readl(LPC32XX_ADC_VALUE(info->adc_base)) &
		ADC_VALUE_MASK;
		complete(&info->completion);

		return IRQ_HANDLED;
		}

		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;

		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;
		}

		iodev = iio_allocate_device(sizeof(struct lpc32xx_adc_info));
		if (!iodev) {
		dev_err(&pdev->dev, "failed allocating iio device\n");
		retval = -ENOMEM;
		goto errout1;
		}

		info = iio_priv(iodev);

		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;
		}

		info->clk = clk_get(&pdev->dev, NULL);
		if (IS_ERR(info->clk)) {
		dev_err(&pdev->dev, "failed getting clock\n");
		goto errout3;
		}

		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;
		}

		retval = request_irq(irq, lpc32xx_adc_isr, 0, MOD_NAME, info);
		if (retval < 0) {
		dev_err(&pdev->dev, "failed requesting interrupt\n");
		goto errout4;
		}

		platform_set_drvdata(pdev, iodev);

		init_completion(&info->completion);

		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);

		retval = iio_device_register(iodev);
		if (retval)
		goto errout5;

		dev_info(&pdev->dev, "LPC32XX ADC driver loaded, IRQ %d\n", irq);

		return 0;

		errout5:
		free_irq(irq, iodev);
		errout4:
		clk_put(info->clk);
		errout3:
		iounmap(info->adc_base);
		errout2:
		iio_free_device(iodev);
		errout1:
		return retval;
		}

		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);

		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);

		return 0;
		}

		static struct platform_driver lpc32xx_adc_driver = {
		.probe = lpc32xx_adc_probe,
		.remove = __devexit_p(lpc32xx_adc_remove),
		.driver = {
		.name = MOD_NAME,
		.owner = THIS_MODULE,
		},
		};

		module_platform_driver(lpc32xx_adc_driver);

		MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
		MODULE_DESCRIPTION("LPC32XX ADC driver");
		MODULE_LICENSE("GPL");