diff mbox series

[RESEND,v2] ARM: dts: lpc32xx: Revert set default clock rate of HCLK PLL

Message ID 20210203090320.GA3760268@piout.net (mailing list archive)
State Accepted
Commit 5638159f6d93b99ec9743ac7f65563fca3cf413d
Headers show
Series [RESEND,v2] ARM: dts: lpc32xx: Revert set default clock rate of HCLK PLL | expand

Commit Message

Alexandre Belloni Feb. 3, 2021, 9:03 a.m. UTC 
This reverts commit c17e9377aa81664d94b4f2102559fcf2a01ec8e7.

The lpc32xx clock driver is not able to actually change the PLL rate as
this would require reparenting ARM_CLK, DDRAM_CLK, PERIPH_CLK to SYSCLK,
then stop the PLL, update the register, restart the PLL and wait for the
PLL to lock and finally reparent ARM_CLK, DDRAM_CLK, PERIPH_CLK to HCLK
PLL.

Currently, the HCLK driver simply updates the registers but this has no
real effect and all the clock rate calculation end up being wrong. This is
especially annoying for the peripheral (e.g. UARTs, I2C, SPI).

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Tested-by: Gregory CLEMENT <gregory.clement@bootlin.com>
---
Arnd,

This is a very important fix that was sent back in may and october 2019 without
any reply from the maintainers, please consider applying it so it can be
backported on v5.10.

 arch/arm/boot/dts/lpc32xx.dtsi | 3 ---
 1 file changed, 3 deletions(-)

Comments

patchwork-bot+linux-soc@kernel.org Feb. 3, 2021, 12:10 p.m. UTC | #1 
Hello:

This patch was applied to soc/soc.git (refs/heads/arm/fixes):

On Wed, 3 Feb 2021 10:03:20 +0100 you wrote:
> This reverts commit c17e9377aa81664d94b4f2102559fcf2a01ec8e7.
> 
> The lpc32xx clock driver is not able to actually change the PLL rate as
> this would require reparenting ARM_CLK, DDRAM_CLK, PERIPH_CLK to SYSCLK,
> then stop the PLL, update the register, restart the PLL and wait for the
> PLL to lock and finally reparent ARM_CLK, DDRAM_CLK, PERIPH_CLK to HCLK
> PLL.
> 
> [...]

Here is the summary with links:
  - [RESEND,v2] ARM: dts: lpc32xx: Revert set default clock rate of HCLK PLL
    https://git.kernel.org/soc/soc/c/5638159f6d93

You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
Arnd Bergmann Feb. 3, 2021, 12:31 p.m. UTC | #2 
From: Arnd Bergmann <arnd@arndb.de>

On Wed, 3 Feb 2021 10:03:20 +0100, Alexandre Belloni wrote:
> This reverts commit c17e9377aa81664d94b4f2102559fcf2a01ec8e7.
> 
> The lpc32xx clock driver is not able to actually change the PLL rate as
> this would require reparenting ARM_CLK, DDRAM_CLK, PERIPH_CLK to SYSCLK,
> then stop the PLL, update the register, restart the PLL and wait for the
> PLL to lock and finally reparent ARM_CLK, DDRAM_CLK, PERIPH_CLK to HCLK
> PLL.
> 
> [...]

Applied to arm/fixes, thanks!

[1/1] ARM: dts: lpc32xx: Revert set default clock rate of HCLK PLL
      commit: 5638159f6d93b99ec9743ac7f65563fca3cf413d

       Arnd
diff mbox series

Patch

diff --git a/arch/arm/boot/dts/lpc32xx.dtsi b/arch/arm/boot/dts/lpc32xx.dtsi
index 3a5cfb0ddb20..c87066d6c995 100644
--- a/arch/arm/boot/dts/lpc32xx.dtsi
+++ b/arch/arm/boot/dts/lpc32xx.dtsi
@@ -326,9 +326,6 @@  clk: clock-controller@0 {
 
 					clocks = <&xtal_32k>, <&xtal>;
 					clock-names = "xtal_32k", "xtal";
-
-					assigned-clocks = <&clk LPC32XX_CLK_HCLK_PLL>;
-					assigned-clock-rates = <208000000>;
 				};
 			};