Messages in this thread | | | From | Martin Blumenstingl <> | Date | Tue, 22 Jun 2021 23:04:55 +0200 | Subject | Re: [PATCH v2 0/3] clk: meson: rounding for fast clocks on 32-bit SoCs |
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Hi Stephen,
On Mon, Jun 7, 2021 at 9:04 AM Jerome Brunet <jbrunet@baylibre.com> wrote: > > > On Fri 04 Jun 2021 at 19:18, Martin Blumenstingl <martin.blumenstingl@googlemail.com> wrote: > > > Hi Jerome, Hi Stephen, > > > > On Mon, May 24, 2021 at 12:37 PM Martin Blumenstingl > > <martin.blumenstingl@googlemail.com> wrote: > >> > >> On the 32-bit Amlogic Meson8/8b/8m2 SoCs we run into a problem with the > >> fast HDMI PLL and it's OD (post-dividers). This clock tree can run at > >> up to approx. 3GHz. > >> This however causes a problem, because these rates require BIT(31) to > >> be usable. Unfortunately this is not the case with clk_ops.round_rate > >> on 32-bit systems. BIT(31) is reserved for the sign (+ or -). > >> > >> clk_ops.determine_rate does not suffer from this limitation. It uses > >> an int to signal any errors and can then take all availble 32 bits for > >> the clock rate. > >> > >> Changes since v1 from [0]: > >> - reworked the first patch so the the existing > >> divider_{ro_}round_rate_parent implementations are using the new > >> divider_{ro_}determine_rate implementations to avoid code duplication > >> (thanks Jerome for the suggestion) > >> - added a patch to switch the default clk_divider_{ro_}ops to use > >> .determine_rate instead of .round_rate as suggested by Jerome > >> (thanks) > >> - dropped a patch for the Meson PLL ops as these are independent from > >> the divider patches and Jerome has applied that one directly (thanks) > >> - added Jerome's Reviewed-by to the meson clk-regmap patch (thanks!) > >> - dropped the RFC prefix > > please let me know what you think about this v2 > > I am asking because clk-divider is widely used, so I'd appreciate if > > this gets some time in linux-next (so for example Kernel CI can test > > this and report issues if there are any). Do you have any comments on this series? I am fine with it skipping 5.14 as it's a change which affects multiple platforms. So I would like to use the time until the trees are opening for patches targeting 5.15 to iron out code-review comments.
> Looks good to me > Reviewed-by: Jerome Brunet <jbrunet@baylibre.com> Thanks Jerome - I'll add it to v3 once I send it (assuming nothing major changes)
Best regards, Martin
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