On Fri, Apr 29, 2016 at 08:04:09AM -0400, Rob Clark wrote: > On Fri, Apr 29, 2016 at 1:32 AM, Vinay Simha <simhavcs at gmail.com> wrote: > > hi, > > > > In nx7, backlight brightness control is controlled by dcs commands of > > MIPI_DCS_SET_DISPLAY_BRIGHTNESS. > > there is no PWM going to panel interface directly as we have in ifc6410/nx5 > > afaiu it is not uncommon to need to control backlight via panel (ie, I > think basically all adaptive-backlight panels). I think the answer is > for these panels, the panel driver would register it's own backlight > driver, rather than get a (pwm, etc) backlight via dt bindings.
Yes, that'd be my recommendation as well. > Possibly if the backlight commands are standardized enough then we > could implement a single drm_panel_dsi_backlight helper which could be > created by any of the dsi adaptive-backlight panels (ie. pass in a > 'struct mipi_dsi_device *').. something like: > > struct drm_panel_dsi_backlight { > struct mipi_panel_dsi_device *link; > ... > } > > struct backlight_device *drm_panel_create_dsi_backlight(struct > mipi_panel_dsi_device *link) > { > struct drm_panel_dsi_backlight *dsi_bl; > ... > return devm_backlight_device_register(&link->dev, ..., dsi_bl, > dsi_bl_ops, props); > } I agree it would make sense to have a DCS specific helper for backlight. I'm somewhat sceptical about the standardization, even though these seem to be part of DCS 1.3. But perhaps we can start by being optimistic. Thierry -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 819 bytes Desc: not available URL: <https://lists.freedesktop.org/archives/dri-devel/attachments/20160502/82179796/attachment.sig>