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    FromBalaji Rao <>
    Subject[PATCH V2 2/7] mfd: PCF50633 adc driver
    DateThu, 18 Dec 2008 11:26:53 +0530
    This patch adds basic support for the PCF50633 ADC. The subtractive mode
    is not supported yet.
    
    Since we don't have adc subsystem, it currently lives in drivers/mfd.
    
    Signed-off-by: Balaji Rao <balajirrao@openmoko.org>
    Cc: Andy Green <andy@openmoko.com>
    Cc: Samuel Ortiz <sameo@openedhand.com>
    ---
     drivers/mfd/Kconfig              |    7 +
     drivers/mfd/Makefile             |    1 
     drivers/mfd/pcf50633-adc.c       |  277 ++++++++++++++++++++++++++++++++++++++
     include/linux/mfd/pcf50633/adc.h |   72 ++++++++++
     4 files changed, 357 insertions(+), 0 deletions(-)
     create mode 100644 drivers/mfd/pcf50633-adc.c
     create mode 100644 include/linux/mfd/pcf50633/adc.h
    diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
    index fb1f0f7..02e3d73 100644
    --- a/drivers/mfd/Kconfig
    +++ b/drivers/mfd/Kconfig
    @@ -162,6 +162,13 @@ config MFD_PCF50633
     	  facilities, and registers devices for the various functions
     	  so that function-specific drivers can bind to them.
     
    +config PCF50633_ADC
    +	tristate "Support for NXP PCF50633 ADC"
    +	depends on MFD_PCF50633
    +	help
    +	 Say yes here if you want to include support for ADC in the
    +	 NXP PCF50633 chip.
    +
     endmenu
     
     menu "Multimedia Capabilities Port drivers"
    diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
    index 6a4add8..7a12b09 100644
    --- a/drivers/mfd/Makefile
    +++ b/drivers/mfd/Makefile
    @@ -34,3 +34,4 @@ obj-$(CONFIG_UCB1400_CORE)	+= ucb1400_core.o
     obj-$(CONFIG_PMIC_DA903X)	+= da903x.o
     
     obj-$(CONFIG_MFD_PCF50633)	+= pcf50633-core.o
    +obj-$(CONFIG_PCF50633_ADC)	+= pcf50633-adc.o
    diff --git a/drivers/mfd/pcf50633-adc.c b/drivers/mfd/pcf50633-adc.c
    new file mode 100644
    index 0000000..f5f1fb0
    --- /dev/null
    +++ b/drivers/mfd/pcf50633-adc.c
    @@ -0,0 +1,277 @@
    +/* NXP PCF50633 ADC Driver
    + *
    + * (C) 2006-2008 by Openmoko, Inc.
    + * Author: Balaji Rao <balajirrao@openmoko.org>
    + * All rights reserved.
    + *
    + * Broken down from monstrous PCF50633 driver mainly by
    + * Harald Welte, Andy Green and Werner Almesberger
    + *
    + *  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.
    + *
    + *  NOTE: This driver does not yet support subtractive ADC mode, which means
    + *  you can do only one measurement per read request.
    + */
    +
    +#include <linux/kernel.h>
    +#include <linux/module.h>
    +#include <linux/init.h>
    +#include <linux/device.h>
    +#include <linux/platform_device.h>
    +#include <linux/completion.h>
    +
    +#include <linux/mfd/pcf50633/core.h>
    +#include <linux/mfd/pcf50633/adc.h>
    +
    +struct pcf50633_adc_request {
    +	int mux;
    +	int avg;
    +	int result;
    +	void (*callback)(struct pcf50633 *, void *, int);
    +	void *callback_param;
    +
    +	/* Used in case of sync requests */
    +	struct completion completion;
    +
    +};
    +
    +#define PCF50633_MAX_ADC_FIFO_DEPTH 8
    +
    +struct pcf50633_adc {
    +	struct pcf50633 *pcf;
    +
    +	/* Private stuff */
    +	struct pcf50633_adc_request *queue[PCF50633_MAX_ADC_FIFO_DEPTH];
    +	int queue_head;
    +	int queue_tail;
    +	struct mutex queue_mutex;
    +};
    +
    +static inline struct pcf50633_adc *__to_adc(struct pcf50633 *pcf)
    +{
    +	return platform_get_drvdata(pcf->adc_pdev);
    +}
    +
    +static void adc_read_setup(struct pcf50633 *pcf, int channel, int avg)
    +{
    +	channel &= PCF50633_ADCC1_ADCMUX_MASK;
    +
    +	/* kill ratiometric, but enable ACCSW biasing */
    +	pcf50633_reg_write(pcf, PCF50633_REG_ADCC2, 0x00);
    +	pcf50633_reg_write(pcf, PCF50633_REG_ADCC3, 0x01);
    +
    +	/* start ADC conversion on selected channel */
    +	pcf50633_reg_write(pcf, PCF50633_REG_ADCC1, channel | avg |
    +		    PCF50633_ADCC1_ADCSTART | PCF50633_ADCC1_RES_10BIT);
    +}
    +
    +static void trigger_next_adc_job_if_any(struct pcf50633 *pcf)
    +{
    +	struct pcf50633_adc *adc = __to_adc(pcf);
    +	int head;
    +
    +	mutex_lock(&adc->queue_mutex);
    +
    +	head = adc->queue_head;
    +
    +	if (!adc->queue[head]) {
    +		mutex_unlock(&adc->queue_mutex);
    +		return;
    +	}
    +	mutex_unlock(&adc->queue_mutex);
    +
    +	adc_read_setup(pcf, adc->queue[head]->mux, adc->queue[head]->avg);
    +}
    +
    +static int
    +adc_enqueue_request(struct pcf50633 *pcf, struct pcf50633_adc_request *req)
    +{
    +	struct pcf50633_adc *adc = __to_adc(pcf);
    +	int head, tail;
    +
    +	mutex_lock(&adc->queue_mutex);
    +
    +	head = adc->queue_head;
    +	tail = adc->queue_tail;
    +
    +	if (adc->queue[tail]) {
    +		mutex_unlock(&adc->queue_mutex);
    +		return -EBUSY;
    +	}
    +
    +	adc->queue[tail] = req;
    +	adc->queue_tail = (tail + 1) & (PCF50633_MAX_ADC_FIFO_DEPTH - 1);
    +
    +	mutex_unlock(&adc->queue_mutex);
    +
    +	trigger_next_adc_job_if_any(pcf);
    +
    +	return 0;
    +}
    +
    +static void
    +pcf50633_adc_sync_read_callback(struct pcf50633 *pcf, void *param, int result)
    +{
    +	struct pcf50633_adc_request *req = param;
    +
    +	req->result = result;
    +	complete(&req->completion);
    +}
    +
    +int pcf50633_adc_sync_read(struct pcf50633 *pcf, int mux, int avg)
    +{
    +	struct pcf50633_adc_request *req;
    +
    +	/* req is freed when the result is ready, in interrupt handler */
    +	req = kzalloc(sizeof(*req), GFP_KERNEL);
    +	if (!req)
    +		return -ENOMEM;
    +
    +	req->mux = mux;
    +	req->avg = avg;
    +	req->callback =  pcf50633_adc_sync_read_callback;
    +	req->callback_param = req;
    +
    +	init_completion(&req->completion);
    +	adc_enqueue_request(pcf, req);
    +	wait_for_completion(&req->completion);
    +
    +	return req->result;
    +}
    +EXPORT_SYMBOL_GPL(pcf50633_adc_sync_read);
    +
    +int pcf50633_adc_async_read(struct pcf50633 *pcf, int mux, int avg,
    +			     void (*callback)(struct pcf50633 *, void *, int),
    +			     void *callback_param)
    +{
    +	struct pcf50633_adc_request *req;
    +
    +	/* req is freed when the result is ready, in interrupt handler */
    +	req = kmalloc(sizeof(*req), GFP_KERNEL);
    +	if (!req)
    +		return -ENOMEM;
    +
    +	req->mux = mux;
    +	req->avg = avg;
    +	req->callback = callback;
    +	req->callback_param = callback_param;
    +
    +	adc_enqueue_request(pcf, req);
    +
    +	return 0;
    +}
    +EXPORT_SYMBOL_GPL(pcf50633_adc_async_read);
    +
    +static int adc_result(struct pcf50633 *pcf)
    +{
    +	u8 adcs1, adcs3;
    +	u16 result;
    +
    +	adcs1 = pcf50633_reg_read(pcf, PCF50633_REG_ADCS1);
    +	adcs3 = pcf50633_reg_read(pcf, PCF50633_REG_ADCS3);
    +	result = (adcs1 << 2) | (adcs3 & PCF50633_ADCS3_ADCDAT1L_MASK);
    +
    +	dev_dbg(pcf->dev, "adc result = %d\n", result);
    +
    +	return result;
    +}
    +
    +static void pcf50633_adc_irq(int irq, void *data)
    +{
    +	struct pcf50633_adc *adc = data;
    +	struct pcf50633 *pcf = adc->pcf;
    +	struct pcf50633_adc_request *req;
    +	int head;
    +
    +	mutex_lock(&adc->queue_mutex);
    +	head = adc->queue_head;
    +
    +	req = adc->queue[head];
    +	if (WARN_ON(!req)) {
    +		dev_err(pcf->dev, "pcf50633-adc irq: ADC queue empty!\n");
    +		mutex_unlock(&adc->queue_mutex);
    +		return;
    +	}
    +	adc->queue[head] = NULL;
    +	adc->queue_head = (head + 1) &
    +				      (PCF50633_MAX_ADC_FIFO_DEPTH - 1);
    +
    +	mutex_unlock(&adc->queue_mutex);
    +
    +	req->callback(pcf, req->callback_param, adc_result(pcf));
    +	kfree(req);
    +
    +	trigger_next_adc_job_if_any(pcf);
    +}
    +
    +static int __devinit pcf50633_adc_probe(struct platform_device *pdev)
    +{
    +	struct pcf50633_subdev_pdata *pdata = pdev->dev.platform_data;
    +	struct pcf50633_adc *adc;
    +
    +	adc = kzalloc(sizeof(*adc), GFP_KERNEL);
    +	if (!adc)
    +		return -ENOMEM;
    +
    +	adc->pcf = pdata->pcf;
    +	platform_set_drvdata(pdev, adc);
    +
    +	pcf50633_register_irq(pdata->pcf, PCF50633_IRQ_ADCRDY,
    +					pcf50633_adc_irq, adc);
    +
    +	mutex_init(&adc->queue_mutex);
    +
    +	return 0;
    +}
    +
    +static int __devexit pcf50633_adc_remove(struct platform_device *pdev)
    +{
    +	struct pcf50633_adc *adc = platform_get_drvdata(pdev);
    +	int i, head;
    +
    +	pcf50633_free_irq(adc->pcf, PCF50633_IRQ_ADCRDY);
    +
    +	mutex_lock(&adc->queue_mutex);
    +	head = adc->queue_head;
    +
    +	if (WARN_ON(adc->queue[head]))
    +		dev_err(adc->pcf->dev,
    +			"adc driver removed with request pending\n");
    +
    +	for (i = 0; i < PCF50633_MAX_ADC_FIFO_DEPTH; i++)
    +		kfree(adc->queue[i]);
    +
    +	mutex_unlock(&adc->queue_mutex);
    +	kfree(adc);
    +
    +	return 0;
    +}
    +
    +static struct platform_driver pcf50633_adc_driver = {
    +	.driver = {
    +		.name = "pcf50633-adc",
    +	},
    +	.probe = pcf50633_adc_probe,
    +	.remove = __devexit_p(pcf50633_adc_remove),
    +};
    +
    +static int __init pcf50633_adc_init(void)
    +{
    +	return platform_driver_register(&pcf50633_adc_driver);
    +}
    +module_init(pcf50633_adc_init);
    +
    +static void __exit pcf50633_adc_exit(void)
    +{
    +	platform_driver_unregister(&pcf50633_adc_driver);
    +}
    +module_exit(pcf50633_adc_exit);
    +
    +MODULE_AUTHOR("Balaji Rao <balajirrao@openmoko.org>");
    +MODULE_DESCRIPTION("PCF50633 adc driver");
    +MODULE_LICENSE("GPL");
    +MODULE_ALIAS("platform:pcf50633-adc");
    +
    diff --git a/include/linux/mfd/pcf50633/adc.h b/include/linux/mfd/pcf50633/adc.h
    new file mode 100644
    index 0000000..56669b4
    --- /dev/null
    +++ b/include/linux/mfd/pcf50633/adc.h
    @@ -0,0 +1,72 @@
    +/*
    + * adc.h  -- Driver for NXP PCF50633 ADC
    + *
    + * (C) 2006-2008 by Openmoko, Inc.
    + * All rights reserved.
    + *
    + * 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.
    + */
    +
    +#ifndef __LINUX_MFD_PCF50633_ADC_H
    +#define __LINUX_MFD_PCF50633_ADC_H
    +
    +#include <linux/mfd/pcf50633/core.h>
    +#include <linux/platform_device.h>
    +
    +/* ADC Registers */
    +#define PCF50633_REG_ADCC3		0x52
    +#define PCF50633_REG_ADCC2		0x53
    +#define PCF50633_REG_ADCC1		0x54
    +#define PCF50633_REG_ADCS1		0x55
    +#define PCF50633_REG_ADCS2		0x56
    +#define PCF50633_REG_ADCS3		0x57
    +
    +#define PCF50633_ADCC1_ADCSTART		0x01
    +#define PCF50633_ADCC1_RES_10BIT	0x02
    +#define PCF50633_ADCC1_AVERAGE_NO	0x00
    +#define PCF50633_ADCC1_AVERAGE_4	0x04
    +#define PCF50633_ADCC1_AVERAGE_8	0x08
    +#define PCF50633_ADCC1_AVERAGE_16	0x0c
    +#define PCF50633_ADCC1_MUX_BATSNS_RES	0x00
    +#define PCF50633_ADCC1_MUX_BATSNS_SUBTR	0x10
    +#define PCF50633_ADCC1_MUX_ADCIN2_RES	0x20
    +#define PCF50633_ADCC1_MUX_ADCIN2_SUBTR	0x30
    +#define PCF50633_ADCC1_MUX_BATTEMP	0x60
    +#define PCF50633_ADCC1_MUX_ADCIN1	0x70
    +#define PCF50633_ADCC1_AVERAGE_MASK	0x0c
    +#define PCF50633_ADCC1_ADCMUX_MASK	0xf0
    +
    +#define PCF50633_ADCC2_RATIO_NONE	0x00
    +#define PCF50633_ADCC2_RATIO_BATTEMP	0x01
    +#define PCF50633_ADCC2_RATIO_ADCIN1	0x02
    +#define PCF50633_ADCC2_RATIO_BOTH	0x03
    +#define PCF50633_ADCC2_RATIOSETTL_100US 0x04
    +
    +#define PCF50633_ADCC3_ACCSW_EN		0x01
    +#define PCF50633_ADCC3_NTCSW_EN		0x04
    +#define PCF50633_ADCC3_RES_DIV_TWO	0x10
    +#define PCF50633_ADCC3_RES_DIV_THREE	0x00
    +
    +#define PCF50633_ADCS3_REF_NTCSW	0x00
    +#define PCF50633_ADCS3_REF_ACCSW	0x10
    +#define PCF50633_ADCS3_REF_2V0		0x20
    +#define PCF50633_ADCS3_REF_VISA		0x30
    +#define PCF50633_ADCS3_REF_2V0_2	0x70
    +#define PCF50633_ADCS3_ADCRDY		0x80
    +
    +#define PCF50633_ADCS3_ADCDAT1L_MASK	0x03
    +#define PCF50633_ADCS3_ADCDAT2L_MASK	0x0c
    +#define PCF50633_ADCS3_ADCDAT2L_SHIFT	2
    +#define PCF50633_ASCS3_REF_MASK		0x70
    +
    +extern int
    +pcf50633_adc_async_read(struct pcf50633 *pcf, int mux, int avg,
    +		void (*callback)(struct pcf50633 *, void *, int),
    +		void *callback_param);
    +extern int
    +pcf50633_adc_sync_read(struct pcf50633 *pcf, int mux, int avg);
    +
    +#endif /* __LINUX_PCF50633_ADC_H */
    
    
    
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