Date: Thu, 29 Sep 2016 22:29:07 -0400 From: Lee D <embaudarm@gmail.com> To: Thomas Skibo <thomasskibo@yahoo.com> Cc: freebsd-arm <freebsd-arm@freebsd.org> Subject: Re: SD-Card driver modification for Zynq questions Message-ID: <CANC_bnN%2BEey8Dhn2kyWtYC0R_he8Xx9DL8D8VqGzuoL5g29O5Q@mail.gmail.com> In-Reply-To: <02E012FA-342E-4EB7-99F2-733FA7990BDD@yahoo.com>
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On Wed, Sep 28, 2016 at 10:16 AM, Thomas Skibo <thomasskibo@yahoo.com> wrote: > > Why not just set max-frequency to 200Mhz in the DTS file entry? > > —— > Thomas Skibo > thomasskibo@yahoo.com > > I hadn't thought of that. I think you are suggesting that I tell the driver that the clock speed is higher than it is so all of the clock divisors are set higher, which would result in a lower data rate. That's a clever idea, but I think I would actually have to set the max-frequency to 500MHz, since some cards are capable of operating up to 100MHz and my SD-Card slot can only run (safely) at 20MHz. That means at that all normal 25MHz cards would run dramatically slower than they need to. In the event that I can't figure out how to make a new DTS file parameter for max data rate, do you think that my modification is a decent way to accomplish my goal? Thanks, Leehome | help
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