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Date:	Fri, 10 Aug 2012 08:33:25 +0200 (CEST)
From:	Peter Meerwald <pmeerw@...erw.net>
To:	anish kumar <anish198519851985@...il.com>
cc:	myungjoo.ham@...sung.com, cw00.choi@...sung.com,
	linux-kernel@...r.kernel.org, linux-iio@...r.kernel.org,
	anish kumar <anish.singh@...sung.com>
Subject: Re: [PATCH] [PATCH V5]Extcon: adc_jack: adc-jack driver to support
 3.5 pi or simliar devices

Hello,

some nitpicking below; sorry for my late reaction to the patch

regards, p.

> From: anish kumar <anish198519851985@...il.com>
> 
> External connector devices that decides connection information based on
> ADC values may use adc-jack device driver. The user simply needs to
> provide a table of adc range and connection states. Then, extcon
> framework will automatically notify others.
> 
> Changes in V1:
> added Lars-Peter Clausen suggested changes:
> Using macros to get rid of boiler plate code such as devm_kzalloc
> and module_platform_driver.Other changes suggested are related to
> coding guidelines.
> 
> Changes in V2:
> Removed some unnecessary checks and changed the way we are un-regitering
> extcon and freeing the irq while removing.
> 
> Changes in V3:
> Renamed the files to comply with extcon naming.
> 
> Changes in V4:
> Added the cancel_work_sync during removing of driver.
> 
> Changes in this version:
> Added the dependency of IIO in Kconfig.
> 
> Reviewed-by: Lars-Peter Clausen <lars@...afoo.de>
> Signed-off-by: anish kumar <anish.singh@...sung.com>
> Signed-off-by: MyungJoo Ham <myungjoo.ham@...sung.com>
> ---
>  drivers/extcon/Kconfig                 |    6 +
>  drivers/extcon/Makefile                |    1 +
>  drivers/extcon/extcon-adc-jack.c       |  195 ++++++++++++++++++++++++++++++++
>  include/linux/extcon/extcon-adc-jack.h |   73 ++++++++++++
>  4 files changed, 275 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/extcon/extcon-adc-jack.c
>  create mode 100644 include/linux/extcon/extcon-adc-jack.h
> 
> diff --git a/drivers/extcon/Kconfig b/drivers/extcon/Kconfig
> index e175c8e..dd5b01b 100644
> --- a/drivers/extcon/Kconfig
> +++ b/drivers/extcon/Kconfig
> @@ -21,6 +21,12 @@ config EXTCON_GPIO
>  	  Say Y here to enable GPIO based extcon support. Note that GPIO
>  	  extcon supports single state per extcon instance.
>  
> +config EXTCON_ADC_JACK
> +	tristate "ADC Jack extcon support"
> +	depends on IIO
> +	help
> +	  Say Y here to enable extcon device driver based on ADC values.
> +
>  config EXTCON_MAX77693
>  	tristate "MAX77693 EXTCON Support"
>  	depends on MFD_MAX77693
> diff --git a/drivers/extcon/Makefile b/drivers/extcon/Makefile
> index 88961b3..bc7111e 100644
> --- a/drivers/extcon/Makefile
> +++ b/drivers/extcon/Makefile
> @@ -4,6 +4,7 @@
>  
>  obj-$(CONFIG_EXTCON)		+= extcon_class.o
>  obj-$(CONFIG_EXTCON_GPIO)	+= extcon_gpio.o
> +obj-$(CONFIG_EXTCON_ADC_JACK)   += extcon-adc-jack.o
>  obj-$(CONFIG_EXTCON_MAX77693)	+= extcon-max77693.o
>  obj-$(CONFIG_EXTCON_MAX8997)	+= extcon-max8997.o
>  obj-$(CONFIG_EXTCON_ARIZONA)	+= extcon-arizona.o
> diff --git a/drivers/extcon/extcon-adc-jack.c b/drivers/extcon/extcon-adc-jack.c
> new file mode 100644
> index 0000000..5a97a35
> --- /dev/null
> +++ b/drivers/extcon/extcon-adc-jack.c
> @@ -0,0 +1,195 @@
> +/*
> + * drivers/extcon/extcon-adc-jack.c
> + *
> + * Analog Jack extcon driver with ADC-based detection capability.
> + *
> + * Copyright (C) 2012 Samsung Electronics
> + * MyungJoo Ham <myungjoo.ham@...sung.com>
> + *
> + * Modified for calling to IIO to get adc by <anish.singh@...sung.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + */
> +
> +#include <linux/slab.h>
> +#include <linux/device.h>
> +#include <linux/platform_device.h>
> +#include <linux/err.h>
> +#include <linux/interrupt.h>
> +#include <linux/workqueue.h>
> +#include <linux/iio/consumer.h>
> +#include <linux/extcon/extcon-adc-jack.h>
> +#include <linux/extcon.h>
> +
> +/**
> + * struct adc_jack_data - internal data for adc_jack device driver
> + * @edev        - extcon device.
> + * @cable_names - list of supported cables.
> + * @num_cables  - size of cable_names.
> + * @adc_condition       - list of adc value conditions.
> + * @num_condition       - size of adc_condition.

it is num_conditions (not num_condition) in the code below

I suggest t use adc_conditions instead of adc_condition to be in line with 
cable_names (vs. cable_name)

> + * @irq         - irq number of attach/detach event (0 if not exist).
> + * @handling_delay      - interrupt handler will schedule extcon event
> + *                      handling at handling_delay jiffies.
> + * @handler     - extcon event handler called by interrupt handler.
> + * @chan	- iio channel being queried.
> + */
> +struct adc_jack_data {
> +	struct extcon_dev edev;
> +
> +	const char **cable_names;
> +	int num_cables;
> +	struct adc_jack_cond *adc_condition;
> +	int num_conditions;
> +
> +	int irq;
> +	unsigned long handling_delay; /* in jiffies */
> +	struct delayed_work handler;
> +
> +	struct iio_channel *chan;
> +};
> +
> +static void adc_jack_handler(struct work_struct *work)
> +{
> +	struct adc_jack_data *data = container_of(to_delayed_work(work),
> +						  struct adc_jack_data,
> +						  handler);
> +	u32 state = 0;
> +	int ret, adc_val;
> +	int i;
> +
> +	ret = iio_read_channel_raw(data->chan, &adc_val);
> +	if (ret < 0) {
> +		dev_err(data->edev.dev, "read channel() error: %d\n", ret);
> +		return;
> +	}
> +
> +	/* Get state from adc value with adc_condition */
> +	for (i = 0; i < data->num_conditions; i++) {
> +		struct adc_jack_cond *def = &data->adc_condition[i];
> +		if (!def->state)
> +			break;
> +		if (def->min_adc <= adc_val && def->max_adc >= adc_val) {
> +			state = def->state;
> +			break;
> +		}
> +	}
> +	/* if no def has met, it means state = 0 (no cables attached) */
> +
> +	extcon_set_state(&data->edev, state);
> +}
> +
> +static irqreturn_t adc_jack_irq_thread(int irq, void *_data)
> +{
> +	struct adc_jack_data *data = _data;
> +
> +	schedule_delayed_work(&data->handler, data->handling_delay);
> +	return IRQ_HANDLED;
> +}
> +
> +static int __devinit adc_jack_probe(struct platform_device *pdev)
> +{
> +	struct adc_jack_data *data;
> +	struct adc_jack_pdata *pdata = pdev->dev.platform_data;
> +	int i, err = 0;
> +
> +	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
> +	if (!data)
> +		return -ENOMEM;
> +
> +	data->edev.name = pdata->name;
> +
> +	if (pdata->cable_names)
> +		data->edev.supported_cable = pdata->cable_names;
> +	else
> +		data->edev.supported_cable = extcon_cable_name;
> +
> +	/* Check the length of array and set num_cables */
> +	for (i = 0; data->edev.supported_cable[i]; i++)
> +		;
> +	if (i == 0 || i > SUPPORTED_CABLE_MAX) {
> +		err = -EINVAL;
> +		dev_err(&pdev->dev, "error: pdata->cable_names size = %d\n",
> +			i - 1);
> +		goto out;
> +	}
> +	data->num_cables = i;
> +
> +	if (!pdata->adc_condition ||
> +	    !pdata->adc_condition[0].state) {
> +		err = -EINVAL;
> +		dev_err(&pdev->dev, "error: adc_condition not defined.\n");
> +		goto out;
> +	}
> +	data->adc_condition = pdata->adc_condition;
> +
> +	/* Check the length of array and set num_conditions */
> +	for (i = 0; data->adc_condition[i].state; i++)
> +		;
> +	data->num_conditions = i;
> +
> +	data->chan = iio_channel_get(dev_name(&pdev->dev),
> +						pdata->consumer_channel);
> +	if (IS_ERR(data->chan)) {
> +		err = PTR_ERR(data->chan);
> +		goto out;
> +	}
> +
> +	data->handling_delay = msecs_to_jiffies(pdata->handling_delay_ms);
> +
> +	INIT_DELAYED_WORK_DEFERRABLE(&data->handler, adc_jack_handler);
> +
> +	platform_set_drvdata(pdev, data);
> +
> +	err = extcon_dev_register(&data->edev, &pdev->dev);
> +	if (err)
> +		goto out;
> +
> +	data->irq = platform_get_irq(pdev, 0);
> +	if (!data->irq) {
> +		dev_err(&pdev->dev, "platform_get_irq failed\n");
> +		err = -ENODEV;
> +		goto err_irq;
> +	}
> +
> +	err = request_any_context_irq(data->irq, adc_jack_irq_thread,
> +				pdata->irq_flags, pdata->name, data);
> +
> +	if (err) {
> +		dev_err(&pdev->dev, "error: irq %d\n", data->irq);
> +		err = -EINVAL;
> +		goto err_irq;
> +	}
> +
> +	goto out;
> +
> +err_irq:
> +	extcon_dev_unregister(&data->edev);
> +out:
> +	return err;
> +}
> +
> +static int __devexit adc_jack_remove(struct platform_device *pdev)
> +{
> +	struct adc_jack_data *data = platform_get_drvdata(pdev);
> +
> +	free_irq(data->irq, data);
> +	cancel_work_sync(&data->handler.work);
> +	extcon_dev_unregister(&data->edev);
> +
> +	return 0;
> +}
> +
> +static struct platform_driver adc_jack_driver = {
> +	.probe		= adc_jack_probe,
> +	.remove		= __devexit_p(adc_jack_remove),
> +	.driver		= {
> +		.name	= "adc-jack",
> +		.owner	= THIS_MODULE,
> +	},
> +};
> +
> +module_platform_driver(adc_jack_driver);
> diff --git a/include/linux/extcon/extcon-adc-jack.h b/include/linux/extcon/extcon-adc-jack.h
> new file mode 100644
> index 0000000..c350615
> --- /dev/null
> +++ b/include/linux/extcon/extcon-adc-jack.h
> @@ -0,0 +1,73 @@
> +/*
> + * include/linux/extcon/extcon-adc-jack.h
> + *
> + * Analog Jack extcon driver with ADC-based detection capability.
> + *
> + * Copyright (C) 2012 Samsung Electronics
> + * MyungJoo Ham <myungjoo.ham@...sung.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + */
> +
> +#ifndef _EXTCON_ADC_JACK_H_
> +#define _EXTCON_ADC_JACK_H_ __FILE__
> +
> +#include <linux/module.h>
> +#include <linux/extcon.h>
> +
> +/**
> + * struct adc_jack_cond - condition to use an extcon state
> + * @state	- the corresponding extcon state (if 0, this struct denotes
> + *		the last adc_jack_cond element among the array)
> + * @min_adc	- min adc value for this condition
> + * @max_adc	- max adc value for this condition
> + *
> + * For example, if { .state = 0x3, .min_adc = 100, .max_adc = 200}, it means
> + * that if ADC value is between (inclusive) 100 and 200, than the cable 0 and
> + * 1 are attached (1<<0 | 1<<1 == 0x3)
> + *
> + * Note that you don't need to describe condition for "no cable attached"
> + * because when no adc_jack_cond is met, state = 0 is automatically chosen.
> + */
> +struct adc_jack_cond {
> +	u32 state; /* extcon state value. 0 if invalid */
> +	u32 min_adc;
> +	u32 max_adc;
> +};
> +
> +/**
> + * struct adc_jack_pdata - platform data for adc jack device.
> + * @name	- name of the extcon device. If null, "adc-jack" is used.
> + * @consumer_channel - Unique name to identify the channel on the consumer
> + *                   side. This typically describes the channels use within

channels use_d_ within

> + *                   the consumer. E.g. 'battery_voltage'
> + * @cable_names	- array of cable names ending with null. If the array itself
> + *		if null, extcon standard cable names are chosen.
> + * @adc_contition	- array of struct adc_jack_cond conditions ending

adc_con_d_ition
should maybe be adc_conditions

> + *			with .state = 0 entry. This describes how to decode
> + *			adc values into extcon state.
> + * @irq_flags	- irq flags used for the @irq
> + * @handling_delay_ms	- in some devices, we need to read ADC value some
> + *			milli-seconds after the interrupt occurs. You may
> + *			describe such delays with @handling_delay_ms, which
> + *			is rounded-off by jiffies.
> + */
> +struct adc_jack_pdata {
> +	const char *name;
> +	const char *consumer_channel;
> +	/*
> +	 * NULL if standard extcon names are used.
> +	 * The last entry should be NULL
> +	 */
> +	const char **cable_names;
> +	/* The last entry's state should be 0 */
> +	struct adc_jack_cond *adc_condition;
> +
> +	unsigned long irq_flags;
> +	unsigned long handling_delay_ms; /* in ms */
> +};
> +
> +#endif /* _EXTCON_ADC_JACK_H */
> 

-- 

Peter Meerwald
+43-664-2444418 (mobile)
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