Extcon: adc_jack: adc-jack driver to support 3.5 pi or simliar devices

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 V5:
Added the dependency of IIO in Kconfig.

Changes in V6:
Some nitpicks related to naming.

Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: anish kumar <anish.singh@samsung.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
anish kumar 2012-08-10 00:29:43 -07:00 committed by Greg Kroah-Hartman
parent 34efe4dc47
commit 980d792981
4 changed files with 275 additions and 0 deletions

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@ -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

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@ -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

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@ -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@samsung.com>
*
* Modified for calling to IIO to get adc by <anish.singh@samsung.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_conditions - list of adc value conditions.
* @num_conditions - size of adc_conditions.
* @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_conditions;
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_conditions */
for (i = 0; i < data->num_conditions; i++) {
struct adc_jack_cond *def = &data->adc_conditions[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_conditions ||
!pdata->adc_conditions[0].state) {
err = -EINVAL;
dev_err(&pdev->dev, "error: adc_conditions not defined.\n");
goto out;
}
data->adc_conditions = pdata->adc_conditions;
/* Check the length of array and set num_conditions */
for (i = 0; data->adc_conditions[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);

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@ -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@samsung.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 used 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_contitions - array of struct adc_jack_cond conditions ending
* 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_conditions;
unsigned long irq_flags;
unsigned long handling_delay_ms; /* in ms */
};
#endif /* _EXTCON_ADC_JACK_H */