Re: Query related to MSR(Magnetic Stripe Reader) Device Driver

[Greg KH <gregkh@linuxfoundation.org>]

On Fri, Feb 15, 2013 at 04:48:33PM +0530, Priyaranjan Das wrote:
> Hi Greg,
> 
> On Thu, Jan 31, 2013 at 11:09 AM, Priyaranjan Das
> <priyaranjan456789@gmail.com> wrote:
> > Hi Greg,
> >
> > On Tue, Jan 29, 2013 at 7:03 PM, Greg KH <gregkh@linuxfoundation.org> wrote:
> >> On Mon, Jan 28, 2013 at 03:25:08PM +0530, Priyaranjan Das wrote:
> >>> Hi Greg,
> >>>
> >>> On Tue, Jan 22, 2013 at 10:06 PM, Greg KH <gregkh@linuxfoundation.org> wrote:
> >>> > On Tue, Jan 22, 2013 at 03:02:32PM +0530, Priyaranjan Das wrote:
> >>> >> Hi All,
> >>> >>
> >>> >> I am working on MSR(Magnetic Stripe Reader) for a product . I wish to
> >>> >> know whether any MSR( Magnetic Stripe/card Reader) driver is available
> >>> >> in the current source or not. I need this for reference. Could anyone
> >>> >> please help me?
> >>> >
> >>> > Most of these types of devices that I have worked with always show up as
> >>> > a keyboard device (ps/2 pass-through or a USB hid device.)  What type of
> >>> > interface does your device present to the operating system?
> >>> >
> >>>
> >>> The MSR will be a part of a SoC. It is  a memory mapped device hence
> >>> there is no interface like USB.
> >>
> >> Ok, that's different.  But how will your driver want to communicate the
> >> reader data to userspace?  That will probably determine where you want
> >> to put it.
> >>
> >> I would recommend making it an input device and sending keystrokes that
> >> you read from the card, so you can properly integrate into userspace
> >> applications that are used to using a card reader.
> >>
> >>> MSR IP contains an ADC which the driver will read and interpret the
> >>> data. I am planning to write a Driver for the same. Will this driver
> >>> fall under drivers/mfd/* ?
> >>
> >> As per the above, I would think drivers/input/ wouldn't you?
> >>
> >> Hope this helps,
> >>
> >
> > Thanks for your help!.
> >
> > Yes, you are right, it should be under drivers/input.
> > I am trying to prepare the design right now.
> >
> >
> 
> The MSR IP can be also be used either as a general purpose ADC or in
> Magnetic stripe card reader mode.The IP supports both the modes and
> provides FIFO for storing ADC data.
> 
> I also got to know about IIO subsystem where  ADC drivers are
> implemented. Our use-case will be to use either Magnetic Stripe reader
> mode or general purpose ADC mode in a given configuration. Can I use
> IIO subsystem for the Magnetic Stripe driver?

The IIO developers would know best about this, not I, sorry.

greg k-h