On 21/12/2016 at 11:28:16 +0100, Gregory CLEMENT wrote : > According to RES-3124064: > > The device supports CPU write and read access to the RTC time register. > However, due to this restriction, read and write from/to internal RTC > register may fail. > > Workaround: > General setup: > 1. Configure the RTC Mbus Bridge Timing Control register (offset 0x184A0) > to value 0xFD4D4FFF > Write RTC WRCLK Period to its maximum value (0x3FF) > Write RTC WRCLK setup to 0x29 > Write RTC WRCLK High Time to 0x53 (default value) > Write RTC Read Output Delay to its maximum value (0x1F) > Mbus - Read All Byte Enable to 0x1 (default value) > 2. Configure the RTC Test Configuration Register (offset 0xA381C) bit3 > to '1' (Reserved, Marvell internal) > > For any RTC register read operation: > 1. Read the requested register 100 times. > 2. Find the result that appears most frequently and use this result > as the correct value. > > For any RTC register write operation: > 1. Issue two dummy writes of 0x0 to the RTC Status register (offset > 0xA3800). > 2. Write the time to the RTC Time register (offset 0xA380C). > > This patch is based on the work of Shaker Daibes > > Signed-off-by: Gregory CLEMENT <gregory.clem...@free-electrons.com> > --- > Hi, > > this patch followed the patch series sent here: > http://lists.infradead.org/pipermail/linux-arm-kernel/2016-December/473232.html > > For now I kept the patch 2 converting to time64_t apart after Russell > King feedback. > > Changelog: > > v2 -> v3: > - Removed unrelated change > - Remove Unnecessary blank line > - Used u32 instead of uint32_t > - use the new errata name: RES-3124064 instead of FE-3124064 > > v1 -> v2: > - merged the patch 1 and 3 > - substantially modified the 1st patch with I think a better > implementation: > - First I do not put anymore more a big array onto the stack as > suggested by Andrew Lunn. > - Then I optimize the way to find the correct value. > > Gregory > > drivers/rtc/rtc-armada38x.c | 118 > +++++++++++++++++++++++++++++++++++--------- > 1 file changed, 95 insertions(+), 23 deletions(-) > Applied, thanks.
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