Re: drv2665 driver placement query

[Lars-Peter Clausen <lars@metafoo.de>]

On 01/12/2012 11:05 PM, Palande, Ameya wrote:
> Hi Lars,
> 
> On Thu, Jan 12, 2012 at 12:09 PM, Lars-Peter Clausen <lars@metafoo.de> wrote:
>> Hi,
>>
>> On 01/12/2012 08:39 PM, Palande, Ameya wrote:
>>> Hi,
>>>
>>> I submitted a driver for Texas Instruments DRV2665 chip for placing it
>>> under "drivers/misc".
>>> But I guess it is more appropriate to put it under "drivers/staging/iio"
>>> Reference: https://lkml.org/lkml/2012/1/10/31
>>
>>>
>>> Here is the description of the chip:
>>>
>>> DRV2665 IC drives piezo actuator which enables a wide variety of
>>> high-resolution haptic effects, including feedback localized to
>>> specific areas of the device, as well as vibrations and pulses that
>>> change in frequency based on how the user is interacting with the
>>> device.
>>>
>>> Can you tell me where should I put it under "staging/iio" ?
>>>
>>
>>
>> I had a short look at your driver and it looks to me as if all it does is
>> expose the raw registers as sysfs attributes. So I think one thing you first
>> have to do is to figure out a generic interface for the device class. How does
>> a application usually use these kinds of devices, how can the interface be
>> abstracted, so it applies to a wider range of devices of this class and not
>> only to this one specific device.
> 
> Workflow for using DRV2665 is:
> 1. Set the desired configuration
> 2. Send waveform data to data register

Well that's basically the work-flow for every driver ;) Setup config, write data.

But the data and config also have a meaning. So what is the high-level task a
software want to perform when setting certain up a configuration?

A good start would probably to break the config register down into it's
different elements and don't expose the raw register anymore.

> 
> I am not sure what kind of generic abstraction I can get out of this chip :(
> 
> The advantages that I feel for writing this driver are:
> 1. DRV2665 probing on i2c bus
> 2. Simple and easy to use interface for user space app through sysfs
> 3. Runtime Power management
> 
> I am not aware of similar devices with which I can compare this chip
> and extract generic interface.
> 
> Cheers,
> Ameya.
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