drm/pl111: Insert delay before powering up PL11x
The old codebase has a delay between enabling and powering up the PL11x. According to the manual for PL110, ARM DDI 0161E page 1-5 and the PL111 manual ARM DDI 0293C page 1-6, the power sequence should be such that once Vdd is stable (which we assume it is at boot) LCDEN is enabled first and then CLPOWER should be enabled "after the signals have stabilized" and this is said to be display-dependent. The old codebase uses 20ms. Reviewed-by:Eric Anholt <eric@anholt.net> Signed-off-by:
Linus Walleij <linus.walleij@linaro.org> Link: https://patchwork.freedesktop.org/patch/msgid/20170908124709.4758-5-linus.walleij@linaro.org
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