Re: [PATCH] IIO: TRIGGER: New sysfs based trigger

[Jonathan Cameron <jic23@cam.ac.uk>]

On 02/02/11 19:21, Hennerich, Michael wrote:
> Jonathan Cameron wrote on 2011-02-02:
>> On 02/02/11 13:30, michael.hennerich@analog.com wrote:
>>> From: Michael Hennerich <michael.hennerich@analog.com>
>>>
>>> This patch adds a new trigger that can be invoked by writing the sysfs
>>> file: trigger_now. This approach can be valuable during automated
>>> testing or in situations, where other trigger methods are not
>>> applicable. For example no RTC or spare GPIOs. Last but not least we
>>> can allow user space applications to produce
>> triggers.
>> Excellent.  Very handy for testing as you say.
>>
>> If we really want to commonly use this from userspace we will want a
>> means of registering more than one such trigger but this does fine for
>> test rigs. To do multiple triggers with this we could either just take
>> a module parameter or have a 'request_trigger' attribute under some
>> parent device.
>> Still that's a question for another day.  The current functionality is
>> enough to be getting on with.
> 
> Well - you can register as many triggers as you want.
> This is what platform_device.id is for.
Good point. I was clearly half asleep last night!

Thanks for the clarification.

Jonathan
> 
> See example below -
> 
> static struct platform_device iio_sysfs_trigger = {
>         .name           = "iio_sysfs_trigger",
>         .id             = 0,
>         .dev = {
>                 .platform_data = NULL,
>         },
> };
> 
> static struct platform_device iio_sysfs_trigger1 = {
>         .name           = "iio_sysfs_trigger",
>         .id             = 1,
>         .dev = {
>                 .platform_data = NULL,
>         },
> };
> 
> 
>         &bfin_dpmc,
> 
> static struct platform_device *my_devices[] __initdata = {
> 
> #if defined(CONFIG_IIO_SYSFS_TRIGGER) || defined(CONFIG_IIO_SYSFS_TRIGGER _MODULE)
>         &iio_sysfs_trigger,
>         &iio_sysfs_trigger1,
> #endif
> }
> 
> In the driver use:
> 
>> +     trig->name = kasprintf(GFP_KERNEL, "sysfstrig%d", pdev->id);
> 
> What the gpio trigger driver does is not necessary
> - it only replicates functionality already provided by the platform device bus.
> 
> -Michael
> 
> 
> Greetings,
> Michael
> 
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