From: Jean-Francois Moine <moinejf@free.fr>
To: "Ondřej Jirman" <megous@megous.com>
Cc: "Maxime Ripard" <maxime.ripard@free-electrons.com>,
"Mark Rutland" <mark.rutland@arm.com>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@vger.kernel.org>,
dev@linux-sunxi.org,
"Michael Turquette" <mturquette@baylibre.com>,
"Stephen Boyd" <sboyd@codeaurora.org>,
"open list" <linux-kernel@vger.kernel.org>,
"Emilio López" <emilio@elopez.com.ar>,
"Chen-Yu Tsai" <wens@csie.org>,
"Rob Herring" <robh+dt@kernel.org>,
"open list:COMMON CLK FRAMEWORK" <linux-clk@vger.kernel.org>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 06/14] ARM: sun8i: clk: Add clk-factor rate application method
Date: Fri, 15 Jul 2016 15:27:56 +0200 [thread overview]
Message-ID: <20160715152756.db7375a7109fed18c2fbf43a@free.fr> (raw)
In-Reply-To: <085e185a-ac76-dd3f-9b0e-a7dc9c0c09f3@megous.com>
On Fri, 15 Jul 2016 12:38:54 +0200
Ondřej Jirman <megous@megous.com> wrote:
> > If so, then yes, trying to switch to the 24MHz oscillator before
> > applying the factors, and then switching back when the PLL is stable
> > would be a nice solution.
> >
> > I just checked, and all the SoCs we've had so far have that
> > possibility, so if it works, for now, I'd like to stick to that.
>
> It would need to be tested. U-boot does the change only once, while the
> kernel would be doing it all the time and between various frequencies
> and PLL settings. So the issues may show up with this solution too.
I don't think this is a good idea: the CPU clock may be changed at any
time with the CPUFreq governor. I don't see the system moving from
1008MHz to 24MHz and then to 1200MHz when some computation is needed!
BTW, Ondřej, in my BPi M2+, I tried to change the CPU clock with your
code at kernel start time from 792MHz to 1008MHz, but the hardware
(arisc?) set an other value, and the system speed was lower than before
(the PLL-CPUx register is 0x90031521 on boot, I want to set it to
xxxx1410 and I read 0x91031f33 - sorry, I did not have a look at the
CPU SD pattern). Do you know why?
--
Ken ar c'hentañ | ** Breizh ha Linux atav! **
Jef | http://moinejf.free.fr/
next prev parent reply other threads:[~2016-07-15 13:28 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20160625034511.7966-1-megous@megous.com>
2016-06-25 3:44 ` [PATCH v2 01/14] ARM: clk: sunxi: Add driver for the H3 THS clock megous
2016-06-25 7:13 ` Maxime Ripard
2016-06-25 15:23 ` Ondřej Jirman
2016-06-28 11:52 ` Maxime Ripard
2016-06-25 3:44 ` [PATCH v2 02/14] thermal: sun8i_ths: Add support for the thermal sensor on Allwinner H3 megous
2016-06-25 7:10 ` Maxime Ripard
2016-06-25 15:12 ` Ondřej Jirman
2016-06-28 11:39 ` Maxime Ripard
2016-06-25 3:45 ` [PATCH v2 03/14] dt-bindings: document sun8i_ths - H3 thermal sensor driver megous
2016-06-28 20:56 ` Rob Herring
2016-06-25 3:45 ` [PATCH v2 04/14] regulator: SY8106A regulator driver megous
2016-06-26 11:26 ` Mark Brown
2016-06-26 15:07 ` Ondřej Jirman
2016-06-27 14:54 ` Mark Brown
2016-06-28 16:27 ` Ondřej Jirman
2016-06-27 15:10 ` Mark Brown
2016-06-25 3:45 ` [PATCH v2 05/14] dt-bindings: document " megous
2016-06-26 11:27 ` Mark Brown
2016-06-26 15:10 ` Ondřej Jirman
2016-06-26 18:52 ` Mark Brown
2016-06-25 3:45 ` [PATCH v2 06/14] ARM: sun8i: clk: Add clk-factor rate application method megous
2016-06-30 20:40 ` Maxime Ripard
2016-07-01 0:50 ` Ondřej Jirman
2016-07-01 5:37 ` Jean-Francois Moine
2016-07-01 6:34 ` Ondřej Jirman
2016-07-01 7:47 ` Jean-Francois Moine
2016-07-15 8:53 ` Maxime Ripard
2016-07-15 10:38 ` Ondřej Jirman
2016-07-15 13:27 ` Jean-Francois Moine [this message]
2016-07-15 13:48 ` Ondřej Jirman
2016-07-15 14:22 ` [linux-sunxi] " Michal Suchanek
2016-07-15 16:33 ` Ondřej Jirman
2016-07-21 9:51 ` Maxime Ripard
2016-07-21 9:48 ` Maxime Ripard
2016-07-21 9:52 ` Ondřej Jirman
2016-07-26 6:32 ` Maxime Ripard
2016-07-28 11:27 ` Changed: sunxi-ng clock code - NKMP clock implementation is wrong Ondřej Jirman
2016-07-28 11:38 ` [linux-sunxi] " Chen-Yu Tsai
2016-07-28 21:00 ` Maxime Ripard
2016-07-28 22:01 ` Ondřej Jirman
2016-07-31 10:31 ` Maxime Ripard
2016-07-31 22:01 ` Ondřej Jirman
2016-08-31 20:25 ` Maxime Ripard
2016-07-01 0:53 ` [PATCH v2 06/14] ARM: sun8i: clk: Add clk-factor rate application method Ondřej Jirman
2016-07-15 8:19 ` Maxime Ripard
2016-06-25 3:45 ` [PATCH v2 07/14] ARM: dts: sun8i: Use sun8i-h3-pll1-clk for pll1 in H3 megous
2016-06-25 3:45 ` [PATCH v2 08/14] ARM: dts: sun8i: Add thermal sensor node to the sun8i-h3.dtsi megous
2016-06-25 3:45 ` [PATCH v2 09/14] ARM: dts: sun8i: Add cpu0 label to sun8i-h3.dtsi megous
2016-06-25 3:45 ` [PATCH v2 10/14] ARM: dts: sun8i: Add r_twi I2C controller megous
2016-06-25 7:16 ` Maxime Ripard
2016-06-25 3:45 ` [PATCH v2 11/14] ARM: dts: sun8i: Add sy8106a regulator to Orange Pi PC megous
2016-06-25 3:45 ` [PATCH v2 12/14] ARM: dts: sun8i: Setup CPU operating points for Onrage PI PC megous
2016-06-25 3:45 ` [PATCH v2 13/14] ARM: dts: sun8i: Add gpio-regulator used on Orange Pi One megous
2016-06-25 7:18 ` Maxime Ripard
2016-06-25 3:45 ` [PATCH v2 14/14] ARM: dts: sun8i: Enable DVFS " megous
2016-06-30 11:13 ` [linux-sunxi] " Michal Suchanek
2016-06-30 14:19 ` Ondřej Jirman
2016-06-30 15:16 ` Michal Suchanek
2016-06-30 15:32 ` Ondřej Jirman
2016-06-30 15:50 ` Michal Suchanek
2016-06-30 15:53 ` Ondřej Jirman
2016-07-01 10:54 ` Michal Suchanek
2016-06-30 14:23 ` Siarhei Siamashka
2016-07-01 1:17 ` Ondřej Jirman
2016-07-22 0:41 ` Ondřej Jirman
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