diff mbox

ARM: dts: imx7d: fix LCDIF clock assignment

Message ID 20161123004204.10851-1-stefan@agner.ch (mailing list archive)
State New, archived
Headers show

Commit Message

Stefan Agner Nov. 23, 2016, 12:42 a.m. UTC
The eLCDIF IP of the i.MX 7 SoC knows multiple clocks and lists them
separately:

Clock      Clock Root              Description
apb_clk    MAIN_AXI_CLK_ROOT       AXI clock
pix_clk    LCDIF_PIXEL_CLK_ROOT    Pixel clock
ipg_clk_s  MAIN_AXI_CLK_ROOT       Peripheral access clock

All of them are switched by a single gate, which is part of the
IMX7D_LCDIF_PIXEL_ROOT_CLK clock. Hence using that clock also for
the AXI bus clock (clock-name "axi") makes sure the gate gets
enabled when accessing registers.

There seem to be no separate AXI display clock, and the clock is
optional. Hence remove the dummy clock.

This fixes kernel freezes when starting the X-Server (which
disables/re-enables the display controller).

Signed-off-by: Stefan Agner <stefan@agner.ch>
---
 arch/arm/boot/dts/imx7s.dtsi | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

Comments

Fabio Estevam Nov. 23, 2016, 11:02 p.m. UTC | #1
On Tue, Nov 22, 2016 at 10:42 PM, Stefan Agner <stefan@agner.ch> wrote:
> The eLCDIF IP of the i.MX 7 SoC knows multiple clocks and lists them
> separately:
>
> Clock      Clock Root              Description
> apb_clk    MAIN_AXI_CLK_ROOT       AXI clock
> pix_clk    LCDIF_PIXEL_CLK_ROOT    Pixel clock
> ipg_clk_s  MAIN_AXI_CLK_ROOT       Peripheral access clock
>
> All of them are switched by a single gate, which is part of the
> IMX7D_LCDIF_PIXEL_ROOT_CLK clock. Hence using that clock also for
> the AXI bus clock (clock-name "axi") makes sure the gate gets
> enabled when accessing registers.
>
> There seem to be no separate AXI display clock, and the clock is
> optional. Hence remove the dummy clock.
>
> This fixes kernel freezes when starting the X-Server (which
> disables/re-enables the display controller).
>
> Signed-off-by: Stefan Agner <stefan@agner.ch>

Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Stefan Agner Dec. 5, 2016, 1:26 a.m. UTC | #2
Hi Shawn

On 2016-11-23 15:02, Fabio Estevam wrote:
> On Tue, Nov 22, 2016 at 10:42 PM, Stefan Agner <stefan@agner.ch> wrote:
>> The eLCDIF IP of the i.MX 7 SoC knows multiple clocks and lists them
>> separately:
>>
>> Clock      Clock Root              Description
>> apb_clk    MAIN_AXI_CLK_ROOT       AXI clock
>> pix_clk    LCDIF_PIXEL_CLK_ROOT    Pixel clock
>> ipg_clk_s  MAIN_AXI_CLK_ROOT       Peripheral access clock
>>
>> All of them are switched by a single gate, which is part of the
>> IMX7D_LCDIF_PIXEL_ROOT_CLK clock. Hence using that clock also for
>> the AXI bus clock (clock-name "axi") makes sure the gate gets
>> enabled when accessing registers.
>>
>> There seem to be no separate AXI display clock, and the clock is
>> optional. Hence remove the dummy clock.
>>
>> This fixes kernel freezes when starting the X-Server (which
>> disables/re-enables the display controller).
>>
>> Signed-off-by: Stefan Agner <stefan@agner.ch>
> 
> Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>

Since this fixes a kernel freeze, is there a chance to get this still in
4.9?

--
Stefan
Shawn Guo Dec. 5, 2016, 2:01 a.m. UTC | #3
Hi Arnd, Olof,

On Sun, Dec 04, 2016 at 05:26:58PM -0800, Stefan Agner wrote:
> Hi Shawn
> 
> On 2016-11-23 15:02, Fabio Estevam wrote:
> > On Tue, Nov 22, 2016 at 10:42 PM, Stefan Agner <stefan@agner.ch> wrote:
> >> The eLCDIF IP of the i.MX 7 SoC knows multiple clocks and lists them
> >> separately:
> >>
> >> Clock      Clock Root              Description
> >> apb_clk    MAIN_AXI_CLK_ROOT       AXI clock
> >> pix_clk    LCDIF_PIXEL_CLK_ROOT    Pixel clock
> >> ipg_clk_s  MAIN_AXI_CLK_ROOT       Peripheral access clock
> >>
> >> All of them are switched by a single gate, which is part of the
> >> IMX7D_LCDIF_PIXEL_ROOT_CLK clock. Hence using that clock also for
> >> the AXI bus clock (clock-name "axi") makes sure the gate gets
> >> enabled when accessing registers.
> >>
> >> There seem to be no separate AXI display clock, and the clock is
> >> optional. Hence remove the dummy clock.
> >>
> >> This fixes kernel freezes when starting the X-Server (which
> >> disables/re-enables the display controller).
> >>
> >> Signed-off-by: Stefan Agner <stefan@agner.ch>
> > 
> > Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
> 
> Since this fixes a kernel freeze, is there a chance to get this still in
> 4.9?

Since we get one more week to the final 4.9, is it possible for you to
send this fix for 4.9 inclusion?  Thanks.

For the patch,

Acked-by: Shawn Guo <shawnguo@kernel.org>

Shawn
Uwe Kleine-König Dec. 5, 2016, 7:06 a.m. UTC | #4
Hello Stefan,

On Sun, Dec 04, 2016 at 05:26:58PM -0800, Stefan Agner wrote:
> Since this fixes a kernel freeze, is there a chance to get this still in
> 4.9?

a Fixes:-Line would be nice then.

Best regards
Uwe
Stefan Agner Dec. 5, 2016, 8:29 p.m. UTC | #5
On 2016-12-04 23:06, Uwe Kleine-König wrote:
> Hello Stefan,
> 
> On Sun, Dec 04, 2016 at 05:26:58PM -0800, Stefan Agner wrote:
>> Since this fixes a kernel freeze, is there a chance to get this still in
>> 4.9?
> 
> a Fixes:-Line would be nice then.

Good point.

Fixes: e8ed73f691bd ("ARM: dts: imx7d: add lcdif support")

--
Stefan
Olof Johansson Dec. 7, 2016, 8:53 p.m. UTC | #6
On Mon, Dec 05, 2016 at 10:01:24AM +0800, Shawn Guo wrote:
> Hi Arnd, Olof,
> 
> On Sun, Dec 04, 2016 at 05:26:58PM -0800, Stefan Agner wrote:
> > Hi Shawn
> > 
> > On 2016-11-23 15:02, Fabio Estevam wrote:
> > > On Tue, Nov 22, 2016 at 10:42 PM, Stefan Agner <stefan@agner.ch> wrote:
> > >> The eLCDIF IP of the i.MX 7 SoC knows multiple clocks and lists them
> > >> separately:
> > >>
> > >> Clock      Clock Root              Description
> > >> apb_clk    MAIN_AXI_CLK_ROOT       AXI clock
> > >> pix_clk    LCDIF_PIXEL_CLK_ROOT    Pixel clock
> > >> ipg_clk_s  MAIN_AXI_CLK_ROOT       Peripheral access clock
> > >>
> > >> All of them are switched by a single gate, which is part of the
> > >> IMX7D_LCDIF_PIXEL_ROOT_CLK clock. Hence using that clock also for
> > >> the AXI bus clock (clock-name "axi") makes sure the gate gets
> > >> enabled when accessing registers.
> > >>
> > >> There seem to be no separate AXI display clock, and the clock is
> > >> optional. Hence remove the dummy clock.
> > >>
> > >> This fixes kernel freezes when starting the X-Server (which
> > >> disables/re-enables the display controller).
> > >>
> > >> Signed-off-by: Stefan Agner <stefan@agner.ch>
> > > 
> > > Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
> > 
> > Since this fixes a kernel freeze, is there a chance to get this still in
> > 4.9?
> 
> Since we get one more week to the final 4.9, is it possible for you to
> send this fix for 4.9 inclusion?  Thanks.
> 
> For the patch,
> 
> Acked-by: Shawn Guo <shawnguo@kernel.org>

Applied, with the fixes line. In the future, please email arm@kernel.org too,
it's easier to make sure we don't miss it that way.


-Olof
Shawn Guo Dec. 8, 2016, 12:54 a.m. UTC | #7
On Wed, Dec 07, 2016 at 12:53:14PM -0800, Olof Johansson wrote:
> Applied, with the fixes line. In the future, please email arm@kernel.org too,
> it's easier to make sure we don't miss it that way.

Noted.  Thanks, Olof.

Shawn
diff mbox

Patch

diff --git a/arch/arm/boot/dts/imx7s.dtsi b/arch/arm/boot/dts/imx7s.dtsi
index 0d7d5ac..2b6cb05 100644
--- a/arch/arm/boot/dts/imx7s.dtsi
+++ b/arch/arm/boot/dts/imx7s.dtsi
@@ -643,9 +643,8 @@ 
 				reg = <0x30730000 0x10000>;
 				interrupts = <GIC_SPI 5 IRQ_TYPE_LEVEL_HIGH>;
 				clocks = <&clks IMX7D_LCDIF_PIXEL_ROOT_CLK>,
-					<&clks IMX7D_CLK_DUMMY>,
-					<&clks IMX7D_CLK_DUMMY>;
-				clock-names = "pix", "axi", "disp_axi";
+					<&clks IMX7D_LCDIF_PIXEL_ROOT_CLK>;
+				clock-names = "pix", "axi";
 				status = "disabled";
 			};
 		};