[4/5] ARM: dts: imxrt1050: remove mmc max-frequency property

Message ID 20221017235602.86250-4-giulio.benetti@benettiengineering.com
State New
Headers
Series [1/5] clk: imx: imxrt1050: fix IMXRT1050_CLK_LCDIF_APB offsets |

Commit Message

Giulio Benetti Oct. 17, 2022, 11:56 p.m. UTC
  According to i.MXRT1050 Reference Manual usdhc supports up to 208Mhz clock
so let's remove max-frequency property in the .dtsi base file and
in case add that property in the board specific .dts file for a specific
device connected to it.

Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
---
 arch/arm/boot/dts/imxrt1050.dtsi | 1 -
 1 file changed, 1 deletion(-)
  

Comments

Bough Chen Oct. 18, 2022, 3:01 a.m. UTC | #1
> -----Original Message-----
> From: Giulio Benetti <giulio.benetti@benettiengineering.com>
> Sent: 2022年10月18日 7:56
> To: devicetree@vger.kernel.org; linux-arm-kernel@lists.infradead.org;
> linux-kernel@vger.kernel.org; linux-clk@vger.kernel.org;
> linux-mmc@vger.kernel.org
> Cc: Stephen Boyd <sboyd@kernel.org>; Bough Chen <haibo.chen@nxp.com>;
> Adrian Hunter <adrian.hunter@intel.com>; Ulf Hansson
> <ulf.hansson@linaro.org>; Giulio Benetti
> <giulio.benetti@benettiengineering.com>
> Subject: [PATCH 4/5] ARM: dts: imxrt1050: remove mmc max-frequency
> property
> 
> According to i.MXRT1050 Reference Manual usdhc supports up to 208Mhz clock

Please double check this. As I know, the i.MXRT1050 and i.MX6/7/8/9 series use the same usdhc IP, maybe include some small difference.
For the usdhc in i.MX6/7/8/9, I confirmed with IC team, the card clock output from usdhc can't be upper than 200MHz, otherwise maybe meet some stable related issue.
So here I think should change to like this:
 max-frequency = <200000000>;


Best Regards
Haibo Chen


> so let's remove max-frequency property in the .dtsi base file and in case add
> that property in the board specific .dts file for a specific device connected to it.
> 
> Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
> ---
>  arch/arm/boot/dts/imxrt1050.dtsi | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/arch/arm/boot/dts/imxrt1050.dtsi
> b/arch/arm/boot/dts/imxrt1050.dtsi
> index 114465e4dde6..0b44cc4ce6ad 100644
> --- a/arch/arm/boot/dts/imxrt1050.dtsi
> +++ b/arch/arm/boot/dts/imxrt1050.dtsi
> @@ -93,7 +93,6 @@ usdhc1: mmc@402c0000 {
>  			bus-width = <4>;
>  			fsl,wp-controller;
>  			no-1-8-v;
> -			max-frequency = <4000000>;
>  			fsl,tuning-start-tap = <20>;
>  			fsl,tuning-step = <2>;
>  			status = "disabled";
> --
> 2.34.1
  
Giulio Benetti Oct. 18, 2022, 5:29 p.m. UTC | #2
Hi Haibo,

On 18/10/22 05:01, Bough Chen wrote:
>> -----Original Message-----
>> From: Giulio Benetti <giulio.benetti@benettiengineering.com>
>> Sent: 2022年10月18日 7:56
>> To: devicetree@vger.kernel.org; linux-arm-kernel@lists.infradead.org;
>> linux-kernel@vger.kernel.org; linux-clk@vger.kernel.org;
>> linux-mmc@vger.kernel.org
>> Cc: Stephen Boyd <sboyd@kernel.org>; Bough Chen <haibo.chen@nxp.com>;
>> Adrian Hunter <adrian.hunter@intel.com>; Ulf Hansson
>> <ulf.hansson@linaro.org>; Giulio Benetti
>> <giulio.benetti@benettiengineering.com>
>> Subject: [PATCH 4/5] ARM: dts: imxrt1050: remove mmc max-frequency
>> property
>>
>> According to i.MXRT1050 Reference Manual usdhc supports up to 208Mhz clock
> 
> Please double check this. As I know, the i.MXRT1050 and i.MX6/7/8/9 series use the same usdhc IP, maybe include some small difference.
> For the usdhc in i.MX6/7/8/9, I confirmed with IC team, the card clock output from usdhc can't be upper than 
200MHz, otherwise maybe meet some stable related issue.

Thanks for poiting, I've double checked and you're right. RM states 
208Mhz but DS states 200Mhz and it makes sense because of HS200.

> So here I think should change to like this:
>   max-frequency = <200000000>;

Ok, I'll send a V2 for this. I wait for other comments on the other 
patches for a bit before.

Best regards
  

Patch

diff --git a/arch/arm/boot/dts/imxrt1050.dtsi b/arch/arm/boot/dts/imxrt1050.dtsi
index 114465e4dde6..0b44cc4ce6ad 100644
--- a/arch/arm/boot/dts/imxrt1050.dtsi
+++ b/arch/arm/boot/dts/imxrt1050.dtsi
@@ -93,7 +93,6 @@  usdhc1: mmc@402c0000 {
 			bus-width = <4>;
 			fsl,wp-controller;
 			no-1-8-v;
-			max-frequency = <4000000>;
 			fsl,tuning-start-tap = <20>;
 			fsl,tuning-step = <2>;
 			status = "disabled";