On 08/06/2012 06:54 AM, anish kumar wrote:
> From: anish kumar <anish198519851985@xxxxxxxxx>
>
> 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.
Hi,
some comments inline.
>
> Signed-off-by: anish kumar <anish.singh@xxxxxxxxxxx>
> ---
> drivers/extcon/Kconfig | 5 +
> drivers/extcon/Makefile | 1 +
> drivers/extcon/adc_jack.c | 183 +++++++++++++++++++++++++++++++++++++++
> include/linux/extcon/adc_jack.h | 108 +++++++++++++++++++++++
> 4 files changed, 297 insertions(+), 0 deletions(-)
> create mode 100644 drivers/extcon/adc_jack.c
> create mode 100644 include/linux/extcon/adc_jack.h
>
[...]
> diff --git a/drivers/extcon/adc_jack.c b/drivers/extcon/adc_jack.c
> new file mode 100644
> index 0000000..fef8334
> --- /dev/null
> +++ b/drivers/extcon/adc_jack.c
> @@ -0,0 +1,183 @@
[...]
> +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);
If you are just going to schedule a delayed work in the interrupt handler you
don't necessarily need a threaded interrupt handler. I'd use
request_any_context_irq to request the IRQ.
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int 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 = kzalloc(sizeof(struct adc_jack_data), GFP_KERNEL);
It makes sense to use devm_kzalloc here.
> + 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 err_alloc;
> + }
> + 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 err_alloc;
> + }
> + 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);
You should check the result of iio_channel_get.
> + data->handling_delay = msecs_to_jiffies(pdata->handling_delay_ms);
> +
> + INIT_DELAYED_WORK_DEFERRABLE(&data->handler, adc_jack_handler);
> +
> + platform_set_drvdata(pdev, data);
> +
> + if (pdata->irq) {
Is the driver actually useful without a interrupt? I mean it wouldn't do much
expect always reporting a unconnected cable.
> + data->irq = pdata->irq;
Usually you'd use platform device resources to set the IRQ and not platform
data. E.g. data->irq = platform_get_irq(pdev, 0);
> +
> + err = request_threaded_irq(data->irq, NULL,
> + 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_initwork;
> + }
> + }
> + err = extcon_dev_register(&data->edev, &pdev->dev);
> + if (err)
> + goto err_irq;
> +
> + data->ready = true;
If you request the irq after you registered the extcon_dev you don't need ready.
> +
> + goto out;
> +
> +err_irq:
> + if (data->irq)
> + free_irq(data->irq, data);
> +err_initwork:
> + cancel_delayed_work_sync(&data->handler);
> +err_alloc:
> + kfree(data);
> +out:
> + return err;
> +}
> +
> +static int __devexit adc_jack_remove(struct platform_device *pdev)
> +{
> + struct adc_jack_data *data = platform_get_drvdata(pdev);
> +
> + extcon_dev_unregister(&data->edev);
> + if (data->irq)
> + free_irq(data->irq, data);
> + platform_set_drvdata(pdev, NULL);
Setting the drvdata to NULL is not necessary.
> + kfree(data);
> +
> + 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,
> + },
> +};
> +
> +static int __init adc_jack_init(void)
> +{
> + return platform_driver_register(&adc_jack_driver);
> +}
> +
> +static void __exit adc_jack_exit(void)
> +{
> + platform_driver_unregister(&adc_jack_driver);
> +}
> +
> +module_init(adc_jack_init);
> +module_exit(adc_jack_exit);
module_platform_driver(adc_jack_driver);
> diff --git a/include/linux/extcon/adc_jack.h b/include/linux/extcon/adc_jack.h
> new file mode 100644
> index 0000000..4d6a1f7
> --- /dev/null
> +++ b/include/linux/extcon/adc_jack.h
> @@ -0,0 +1,108 @@
> +/*
> + * include/linux/extcon/adc_jack.h
> + *
> + * Analog Jack extcon driver with ADC-based detection capability.
> + *
> + * Copyright (C) 2012 Samsung Electronics
> + * MyungJoo Ham <myungjoo.ham@xxxxxxxxxxx>
> + *
> + * 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_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.
> + * @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.
> + * @ready - true if it is safe to run handler.
> + */
> +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;
> +
> + bool ready;
> +};
This struct should not go into the public header. The only one who needs this
is the driver itself.
> +
> +/**
> + * 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
> + * 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
> + * with .state = 0 entry. This describes how to decode
> + * adc values into extcon state.
> + * @irq - IRQ number that is triggerred by cable attach/detach
> + * events. If irq = 0, use should manually update extcon state
> + * with extcon APIs.
> + * @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;
const char * const *
> + /* The last entry's state should be 0 */
> + struct adc_jack_cond *adc_condition;
> +
> + int irq; /* Jack insertion/removal interrupt */
> + unsigned long irq_flags;
> + unsigned long handling_delay_ms; /* in ms */
> +};
> +
> +#endif /* _EXTCON_ADC_JACK_H */
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