From mboxrd@z Thu Jan 1 00:00:00 1970 From: Luc Verhaegen Date: Wed, 13 Aug 2014 07:17:15 +0000 Subject: simplefb: add clock handling Message-Id: <1407914239-12054-1-git-send-email-libv@skynet.be> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-arm-kernel@lists.infradead.org This is needed for the sunxi platform, where the u-boot initialized display engine gets disabled by the clocks framework if certain clocks are not claimed. Once these clocks are disabled, register content is lost, and there is no turning back unless a full display driver is loaded, which kind of beats the purpose of having simplefb running. The lack of clock handling should plague more hardware, but so far rpi is the best known user of simplefb, and its stepmotherly handling of the arm core has kept these sort of issues from the kernel. The sunxi u-boot side code can be found here: https://groups.google.com/forum/#!topic/linux-sunxi/dPs958sIXvY Patch 3 might be controversial, as this does not achieve anything real today, since the status property in dt is only really evaluated when dealing with a nodes memory. It still seems like a good idea to at least flag this memory or node as disabled, as we really have no way back when the clocks get disabled. Luc Verhaegen.