Messages in this thread | | | Subject | Re: [PATCH 4/4] ARM: dts: Fix-up EMMC2 controller's frequency | From | Stefan Wahren <> | Date | Fri, 9 Apr 2021 20:28:59 +0200 |
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Hi Nicolas,
Am 09.04.21 um 12:54 schrieb Nicolas Saenz Julienne: > Hi again, > > On Wed, 2021-04-07 at 16:37 -0400, Alan Cooper wrote: >> Nicolas, >> >> I got a better description of the failure and it looks like the bus >> clock needs to be limited to 300KHz for a 500MHz core clock. >> What's happening is that an internal reset sequence is needed after a >> command timeout and the reset signal needs to be asserted for at least >> 2 ticks of the bus clock. This is done using a 12 bit counter clocked >> by the core clock. That means a 500MHz core clock produces a 122KHz >> reset signal which is too fast for 2 ticks of the 200KHz bus clock >> (100KHz) but is okay for the 300KHz (150Khz) bus clock. > Is there any value in implementing this in a generic way?
i don't have any idea which callback could manipulate the reset duration. Limiting the min clk frequency looks like the less invasive solution to me. Touching the DT isn't recommend.
Best regards
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