Re: [PATCH v2 0/7] drm/i915: Baytrail MIPI DSI support Updated

[Daniel Vetter <daniel@ffwll.ch>]

On Sat, Nov 09, 2013 at 03:19:01PM +0530, Shobhit Kumar wrote:
> Hi All - 
> These patches enhance the current support for MIPI DSI for Baytrail. They
> continue on the sub-encoder design and adds few more dev_ops to handle
> sequence correctly. Major changes are -
> 
> 1. DSI Clock calculation based on pixel clock
> 2. Add new dev_ops for better sequencing the enable/disable path
> 3. Parameterized the hardcoded DSI parameters. These also forms building
>    block for the generic MIPI driver to come in future based on enhancements
>    in VBT. All these parameters are initialized or computed in the sub-encoder
>    driver. Some of them might look unneccesary for now.
> 
>  I am also aware of the drm_bridge support now comming in and will in future
>  migrate from sub-encoder design to drm_bridge.

Just a quick aside: Thierry Reding from nvidia is also working on a DSI
design for the tegra driver. Atm he seems to aim for a full-blown DSI bus
based on his drm_panel patches for getting the panel metadata out of an
ARM DT (we'd use VBT instead). Iirc there's no patches anywhere yet, but
maybe Thierry could share a git branch somewhere with the wip stuff?

Cc'ing Thierry and dri-devel in case a bigger discussion develops.

Cheers, Daniel

> 
> This DSI sequence has been validated with couple of test panels and is working now.
> Still no sub-encoder driver is included and this support will be mostly be disabled
> untill a panel sub-encoder driver is added. Proper detection or VBT is still pending.
> 
> v2: Mostly changes from review comments from Jani Nikula and Ville Syrjala
>     - Split the parameters into new patch
>     - Split the dsi_clk computation and m-n-p modification in separate patches
>     - The DSI sequence refactoring has been splitted into multiple patches and also
>       few code changes are not needed after reworking/relooking at them and have been
>       removed
>     - Backlight enabling has been removed as that depends on platform PMIC driver which
>       is not yet there in upstream kernel. Will be added later.
>     - Other general code cleanup as suggested
>     - drm/i915: Use FLISDSI interface for band gap reset - has no changes and is included 
>       for completeness of the patch set
> 
> Regards
> Shobhit
> 
> Shobhit Kumar (7):
>   drm/i915: Add more dev ops for MIPI sub encoder
>   drm/i915: Use FLISDSI interface for band gap reset
>   drm/i915: Compute dsi_clk from pixel clock
>   drm/i915: Try harder to get best m,n,p values with minimal error
>   drm/i915: Reorganize the DSI enable/disable sequence
>   drm/i915: Remove redundant DSI PLL enabling
>   drm/i915: Parametrize the dphy and other spec specific parameters
> 
>  drivers/gpu/drm/i915/i915_drv.h       |   13 +++
>  drivers/gpu/drm/i915/i915_reg.h       |    1 +
>  drivers/gpu/drm/i915/intel_dsi.c      |  187 ++++++++++++++++++---------------
>  drivers/gpu/drm/i915/intel_dsi.h      |   21 ++++
>  drivers/gpu/drm/i915/intel_dsi_pll.c  |   72 ++++++++++---
>  drivers/gpu/drm/i915/intel_sideband.c |   14 +++
>  6 files changed, 209 insertions(+), 99 deletions(-)
> 
> -- 
> 1.7.9.5
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch