Re: [PATCH v5 0/9] Output raw touch data via V4L2

[Hans Verkuil]

On 06/23/2016 12:08 AM, Nick Dyer wrote:
> This is a series of patches to add output of raw touch diagnostic data via V4L2
> to the Atmel maXTouch and Synaptics RMI4 drivers.
> 
> It's a rewrite of the previous implementation which output via debugfs: it now
> uses a V4L2 device in a similar way to the sur40 driver.
> 
> We have a utility which can read the data and display it in a useful format:
>     https://github.com/ndyer/heatmap/commits/heatmap-v4l
> 
> These patches are also available from
>     https://github.com/ndyer/linux/commits/v4l-touch-2016-06-22
> 
> Changes in v5 (Hans Verkuil review):
> - Update v4l2-core:
>   - Add VFL_TYPE_TOUCH, V4L2_BUF_TYPE_TOUCH_CAPTURE and V4L2_CAP_TOUCH

The use of V4L2_CAP_TOUCH and V4L2_BUF_TYPE_TOUCH_CAPTURE is very inconsistent.
What is the rationale of adding V4L2_BUF_TYPE_TOUCH_CAPTURE? I can't remember
asking for it.

And wouldn't the use of V4L2_BUF_TYPE_TOUCH_CAPTURE break userspace for sur40?

I'm ambiguous towards having a V4L2_BUF_TYPE_TOUCH_CAPTURE, to be honest.

I would also recommend renaming V4L2_CAP_TOUCH to V4L2_CAP_TOUCH_CAPTURE.

I can imagine an embedded usb gadget device that outputs touch data to a PC.

Regards,

	Hans

>   - Change V4L2_INPUT_TYPE_TOUCH_SENSOR to V4L2_INPUT_TYPE_TOUCH
>   - Improve DocBook documentation
>   - Add FMT definitions for touch data
>   - Note this will need the latest version of the heatmap util
> - Synaptics RMI4 driver:
>   - Remove some less important non full frame report types
>   - Switch report type names to const char * array
>   - Move a static array to inside context struct
> - Split sur40 changes to a separate commit
> 
> Changes in v4:
> - Address nits from the input side in atmel_mxt_ts patches (Dmitry Torokhov)
> - Add Synaptics RMI4 F54 support patch
> 
> Changes in v3:
> - Address V4L2 review comments from Hans Verkuil
> - Run v4l-compliance and fix all issues - needs minor patch here:
>   https://github.com/ndyer/v4l-utils/commit/cf50469773f
> 
> Changes in v2:
> - Split pixfmt changes into separate commit and add DocBook
> - Introduce VFL_TYPE_TOUCH_SENSOR and /dev/v4l-touch
> - Remove "single node" support for now, it may be better to treat it as
>   metadata later
> - Explicitly set VFL_DIR_RX
> - Fix Kconfig
> 
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