From: Eric Anholt <eric@anholt.net>
To: Boris Brezillon <boris.brezillon@free-electrons.com>,
Mike Turquette <mturquette@baylibre.com>,
Stephen Boyd <sboyd@codeaurora.org>,
linux-clk@vger.kernel.org
Cc: Florian Fainelli <f.fainelli@gmail.com>,
Ray Jui <rjui@broadcom.com>,
Scott Branden <sbranden@broadcom.com>,
bcm-kernel-feedback-list@broadcom.com,
Stephen Warren <swarren@wwwdotorg.org>,
Lee Jones <lee@kernel.org>,
linux-rpi-kernel@lists.infradead.org,
linux-arm-kernel@lists.infradead.org,
Boris Brezillon <boris.brezillon@free-electrons.com>
Subject: Re: [PATCH 1/2] clk: bcm: Support rate change propagation on bcm2835 clocks
Date: Fri, 02 Dec 2016 11:01:09 -0800 [thread overview]
Message-ID: <87lgvyf956.fsf@eliezer.anholt.net> (raw)
In-Reply-To: <1480626020-20031-2-git-send-email-boris.brezillon@free-electrons.com>
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Boris Brezillon <boris.brezillon@free-electrons.com> writes:
> Some peripheral clocks, like the VEC (Video EnCoder) clock need to be set
> to a precise rate (in our case 108MHz). With the current implementation,
> where peripheral clocks are not allowed to forward rate change requests
> to their parents, it is impossible to match this requirement unless the
> bootloader has configured things correctly, or a specific rate has been
> assigned through the DT (with the assigned-clk-rates property).
>
> Add a new field to struct bcm2835_clock_data to specify which parent
> clocks accept rate change propagation, and support set rate propagation
> in bcm2835_clock_determine_rate().
>
> Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
A possible simplification would be to limit VEC to only PLLH_AUX, since
that was how the HW designers intended it to be used. Then you could
just have SET_RATE_PARENT flag, rather than the bitfield.
Still, this seems to be correct and fixes the bug. Both patches are:
Reviewed-by: Eric Anholt <eric@anholt.net>
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From: eric@anholt.net (Eric Anholt)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 1/2] clk: bcm: Support rate change propagation on bcm2835 clocks
Date: Fri, 02 Dec 2016 11:01:09 -0800 [thread overview]
Message-ID: <87lgvyf956.fsf@eliezer.anholt.net> (raw)
In-Reply-To: <1480626020-20031-2-git-send-email-boris.brezillon@free-electrons.com>
Boris Brezillon <boris.brezillon@free-electrons.com> writes:
> Some peripheral clocks, like the VEC (Video EnCoder) clock need to be set
> to a precise rate (in our case 108MHz). With the current implementation,
> where peripheral clocks are not allowed to forward rate change requests
> to their parents, it is impossible to match this requirement unless the
> bootloader has configured things correctly, or a specific rate has been
> assigned through the DT (with the assigned-clk-rates property).
>
> Add a new field to struct bcm2835_clock_data to specify which parent
> clocks accept rate change propagation, and support set rate propagation
> in bcm2835_clock_determine_rate().
>
> Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
A possible simplification would be to limit VEC to only PLLH_AUX, since
that was how the HW designers intended it to be used. Then you could
just have SET_RATE_PARENT flag, rather than the bitfield.
Still, this seems to be correct and fixes the bug. Both patches are:
Reviewed-by: Eric Anholt <eric@anholt.net>
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next prev parent reply other threads:[~2016-12-02 19:01 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-01 21:00 [PATCH 0/2] clk: bcm2835: Propage rate change to PLLH Boris Brezillon
2016-12-01 21:00 ` Boris Brezillon
2016-12-01 21:00 ` [PATCH 1/2] clk: bcm: Support rate change propagation on bcm2835 clocks Boris Brezillon
2016-12-01 21:00 ` Boris Brezillon
2016-12-02 19:01 ` Eric Anholt [this message]
2016-12-02 19:01 ` Eric Anholt
2016-12-02 19:50 ` Boris Brezillon
2016-12-02 19:50 ` Boris Brezillon
2016-12-02 21:13 ` Eric Anholt
2016-12-02 21:13 ` Eric Anholt
2016-12-08 23:06 ` Stephen Boyd
2016-12-08 23:06 ` Stephen Boyd
2016-12-01 21:00 ` [PATCH 2/2] clk: bcm: Allow rate change propagation to PLLH_AUX on VEC clock Boris Brezillon
2016-12-01 21:00 ` Boris Brezillon
2016-12-08 23:06 ` Stephen Boyd
2016-12-08 23:06 ` Stephen Boyd
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