Re: [U-Boot] [PATCH v2 7/9] am33xx: support ti814x mmc reference clock
On Sun, Mar 03, 2013 at 10:34:08PM +0000, Peter Korsgaard wrote:
"Matt" == Matt Porter mporter@ti.com writes:
Matt> TI814x has a 192MHz hsmmc reference clock. Select that clock rate Matt> when building for TI814x.
Matt> Signed-off-by: Matt Porter mporter@ti.com
Acked-by: Peter Korsgaard jacmet@sunsite.dk
Did you figure out why it was working for you with 96 MHz ref?
Unfortunately not at a root cause level. Unless I'm missing something I would have expected the calculations from the supplied 96 MHz ref clock to result in 2x the clock the SD card can handle due to the incorrect divider. However, with the LA attached, I found that a 2-3 MHz SDCLK was being generated after the capability probe occurs. Odd and incorrect, but functional. After switching to 192MHz I was able to sample a nominal 25MHz SDCLK as expected on a regular SD card advertising that as its capability. I don't like it but I'm going to mark this down as "something undocumented" as I only have PG1.0 silicon but can't find an errata sheet for that version right now.
-Matt
"Matt" == Matt Porter mporter@ti.com writes:
Hi,
Did you figure out why it was working for you with 96 MHz ref?
Matt> Unfortunately not at a root cause level. Unless I'm missing Matt> something I would have expected the calculations from the Matt> supplied 96 MHz ref clock to result in 2x the clock the SD card Matt> can handle due to the incorrect divider. However, with the LA Matt> attached, I found that a 2-3 MHz SDCLK was being generated after Matt> the capability probe occurs. Odd and incorrect, but Matt> functional. After switching to 192MHz I was able to sample a Matt> nominal 25MHz SDCLK as expected on a regular SD card advertising Matt> that as its capability. I don't like it but I'm going to mark Matt> this down as "something undocumented" as I only have PG1.0 Matt> silicon but can't find an errata sheet for that version right Matt> now.
Ok, thanks for the info.
participants (2)
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Matt Porter -
Peter Korsgaard