[PATCH] ARM: dts: dra7: Support QSPI MODE-0 operation at 64MHz

[PATCH] ARM: dts: dra7: Support QSPI MODE-0 operation at 64MHz

[Vignesh R]

According to Data Manual(SPRS915P) of AM57x, TI QSPI controller on
DRA74(rev 1.1+) can support up to 64MHz in MODE-0, whereas MODE-3 is
limited to 48MHz. Hence, switch to MODE-0 for better throughput.

Signed-off-by: Vignesh R <vigneshr-l0cyMroinI0@public.gmane.org>
---
 arch/arm/boot/dts/dra7-evm.dts | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/arch/arm/boot/dts/dra7-evm.dts b/arch/arm/boot/dts/dra7-evm.dts
index cfc24e52244e..15f10bdc8c31 100644
--- a/arch/arm/boot/dts/dra7-evm.dts
+++ b/arch/arm/boot/dts/dra7-evm.dts
@@ -653,15 +653,13 @@
 	pinctrl-names = "default";
 	pinctrl-0 = <&qspi1_pins>;
 
-	spi-max-frequency = <48000000>;
+	spi-max-frequency = <64000000>;
 	m25p80@0 {
 		compatible = "s25fl256s1";
-		spi-max-frequency = <48000000>;
+		spi-max-frequency = <64000000>;
 		reg = <0>;
 		spi-tx-bus-width = <1>;
 		spi-rx-bus-width = <4>;
-		spi-cpol;
-		spi-cpha;
 		#address-cells = <1>;
 		#size-cells = <1>;
 
-- 
2.7.1

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Re: [PATCH] ARM: dts: dra7: Support QSPI MODE-0 operation at 64MHz

[Tony Lindgren]

Hi,

* Vignesh R <vigneshr-l0cyMroinI0@public.gmane.org> [160224 20:49]:
> According to Data Manual(SPRS915P) of AM57x, TI QSPI controller on
> DRA74(rev 1.1+) can support up to 64MHz in MODE-0, whereas MODE-3 is
> limited to 48MHz. Hence, switch to MODE-0 for better throughput.
> 
> Signed-off-by: Vignesh R <vigneshr-l0cyMroinI0@public.gmane.org>
> ---
>  arch/arm/boot/dts/dra7-evm.dts | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/arm/boot/dts/dra7-evm.dts b/arch/arm/boot/dts/dra7-evm.dts
> index cfc24e52244e..15f10bdc8c31 100644
> --- a/arch/arm/boot/dts/dra7-evm.dts
> +++ b/arch/arm/boot/dts/dra7-evm.dts
> @@ -653,15 +653,13 @@
>  	pinctrl-names = "default";
>  	pinctrl-0 = <&qspi1_pins>;
>  
> -	spi-max-frequency = <48000000>;
> +	spi-max-frequency = <64000000>;
>  	m25p80@0 {
>  		compatible = "s25fl256s1";
> -		spi-max-frequency = <48000000>;
> +		spi-max-frequency = <64000000>;
>  		reg = <0>;
>  		spi-tx-bus-width = <1>;
>  		spi-rx-bus-width = <4>;
> -		spi-cpol;
> -		spi-cpha;
>  		#address-cells = <1>;
>  		#size-cells = <1>;
>  

Do we have any earlier pre DRA74(rev 1.1)versions in use too?

What about the spi-cpol and spi-cpha changes? Those should be
at least documented?

Regards,

Tony
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Re: [PATCH] ARM: dts: dra7: Support QSPI MODE-0 operation at 64MHz

[Vignesh R]

Hi,

On 02/27/2016 12:43 AM, Tony Lindgren wrote:
> Hi,
> 
> * Vignesh R <vigneshr@ti.com> [160224 20:49]:
>> According to Data Manual(SPRS915P) of AM57x, TI QSPI controller on
>> DRA74(rev 1.1+) can support up to 64MHz in MODE-0, whereas MODE-3 is
>> limited to 48MHz. Hence, switch to MODE-0 for better throughput.
>>
>> Signed-off-by: Vignesh R <vigneshr@ti.com>
>> ---
>>  arch/arm/boot/dts/dra7-evm.dts | 6 ++----
>>  1 file changed, 2 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/arm/boot/dts/dra7-evm.dts b/arch/arm/boot/dts/dra7-evm.dts
>> index cfc24e52244e..15f10bdc8c31 100644
>> --- a/arch/arm/boot/dts/dra7-evm.dts
>> +++ b/arch/arm/boot/dts/dra7-evm.dts
>> @@ -653,15 +653,13 @@
>>  	pinctrl-names = "default";
>>  	pinctrl-0 = <&qspi1_pins>;
>>  
>> -	spi-max-frequency = <48000000>;
>> +	spi-max-frequency = <64000000>;
>>  	m25p80@0 {
>>  		compatible = "s25fl256s1";
>> -		spi-max-frequency = <48000000>;
>> +		spi-max-frequency = <64000000>;
>>  		reg = <0>;
>>  		spi-tx-bus-width = <1>;
>>  		spi-rx-bus-width = <4>;
>> -		spi-cpol;
>> -		spi-cpha;
>>  		#address-cells = <1>;
>>  		#size-cells = <1>;
>>  
> 
> Do we have any earlier pre DRA74(rev 1.1)versions in use too?

Yes, there are pre 1.1 boards (production boards are all rev 1.1+), but
QSPI is broken on them due to erratas (even w/o this patch).

> 
> What about the spi-cpol and spi-cpha changes? Those should be
> at least documented?
> 

Ok, I will add a NOTE in the documentation saying "spi-cpol" and
"spi-cpha" are not supported by ti-qspi in
Documentation/devicetree/bindings/spi/ti_qspi.txt.

-- 
Regards
Vignesh