tree 06c484317c8388e9b8478c7b7d19773b2bc9a457
parent 24e9e6bf5b6fea63124df0009d2ffa21c6a34392
author Claudiu Beznea <claudiu.beznea@microchip.com> 1576672105 +0200
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1581715867 -0500

drm: atmel-hlcdc: enable clock before configuring timing engine

[ Upstream commit 2c1fb9d86f6820abbfaa38a6836157c76ccb4e7b ]

Changing pixel clock source without having this clock source enabled
will block the timing engine and the next operations after (in this case
setting ATMEL_HLCDC_CFG(5) settings in atmel_hlcdc_crtc_mode_set_nofb()
will fail). It is recomended (although in datasheet this is not present)
to actually enabled pixel clock source before doing any changes on timing
enginge (only SAM9X60 datasheet specifies that the peripheral clock and
pixel clock must be enabled before using LCD controller).

Fixes: 1a396789f65a ("drm: add Atmel HLCDC Display Controller support")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Boris Brezillon <boris.brezillon@free-electrons.com>
Cc: <stable@vger.kernel.org> # v4.0+
Link: https://patchwork.freedesktop.org/patch/msgid/1576672109-22707-3-git-send-email-claudiu.beznea@microchip.com
Signed-off-by: Sasha Levin <sashal@kernel.org>