Re: [PATCH v3 21/24] media: imx: Add MIPI CSI-2 Receiver subdev driver

[Russell King - ARM Linux]

On Wed, Feb 08, 2017 at 03:23:53PM -0800, Steve Longerbeam wrote:
> >Actually, this exact function already exists as dw_mipi_dsi_phy_write in
> >drivers/gpu/drm/rockchip/dw-mipi-dsi.c, and it looks like the D-PHY
> >register 0x44 might contain a field called HSFREQRANGE_SEL.
> 
> Thanks for pointing out drivers/gpu/drm/rockchip/dw-mipi-dsi.c.
> It's clear from that driver that there probably needs to be a fuller
> treatment of the D-PHY programming here, but I don't know where
> to find the MIPI CSI-2 D-PHY documentation for the i.MX6. The code
> in imxcsi2_reset() was also pulled from FSL, and that's all I really have
> to go on for the D-PHY programming. I assume the D-PHY is also a
> Synopsys core, like the host controller, but the i.MX6 manual doesn't
> cover it.

Why exactly?  What problems are you seeing that would necessitate a
more detailed programming of the D-PHY?  From my testing, I can wind
a 2-lane MIPI bus on iMX6D from 912Mbps per lane down to (eg) 308Mbps
per lane with your existing code without any issues.

-- 
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