| Message ID | 20221117105249.115649-6-tudor.ambarus@microchip.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | spi: Introduce spi-cs-setup-ns dt property | expand |
Hi Tudor, On 17/11/2022 at 11:52, Tudor Ambarus wrote: > sama5d27-wlsom1 populates an sst26vf064b SPI NOR flash. Its maximum > operating frequency for 2.7-3.6V is 104 MHz. As the flash is operated > at 3.3V, increase its maximum supported frequency to 104MHz. The > increasing of the spi-max-frequency value requires the setting of the > "CE# Not Active Hold Time", thus set the spi-cs-setup-ns to a value of 7. > > The sst26vf064b datasheet specifies just a minimum value for the > "CE# Not Active Hold Time" and it advertises it to 5 ns. There's no > maximum time specified. I determined experimentally that 5 ns for the > spi-cs-setup-ns is not enough when the flash is operated close to its > maximum frequency and tests showed that 7 ns is just fine, so set the > spi-cs-setup-ns dt property to 7. > > With the increase of frequency the reads are now faster with ~37%. > > Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com> > --- > arch/arm/boot/dts/at91-sama5d27_wlsom1.dtsi | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/arm/boot/dts/at91-sama5d27_wlsom1.dtsi b/arch/arm/boot/dts/at91-sama5d27_wlsom1.dtsi > index 83bcf9fe0152..20caf40b4755 100644 > --- a/arch/arm/boot/dts/at91-sama5d27_wlsom1.dtsi > +++ b/arch/arm/boot/dts/at91-sama5d27_wlsom1.dtsi > @@ -220,7 +220,8 @@ qspi1_flash: flash@0 { > #size-cells = <1>; > compatible = "jedec,spi-nor"; > reg = <0>; > - spi-max-frequency = <80000000>; > + spi-max-frequency = <104000000>; > + spi-cs-setup-ns = /bits/ 16 <7>; Following the different changes that happened to this property after this post, am I right saying that this must now be changed to: spi-cs-setup-delay-ns = <7>; ? Thanks for your insight. Best regards, Nicolas > spi-rx-bus-width = <4>; > spi-tx-bus-width = <4>; > m25p,fast-read;
On 3/28/23 09:51, Nicolas Ferre wrote: > Hi Tudor, Hi! > > On 17/11/2022 at 11:52, Tudor Ambarus wrote: >> sama5d27-wlsom1 populates an sst26vf064b SPI NOR flash. Its maximum >> operating frequency for 2.7-3.6V is 104 MHz. As the flash is operated >> at 3.3V, increase its maximum supported frequency to 104MHz. The >> increasing of the spi-max-frequency value requires the setting of the >> "CE# Not Active Hold Time", thus set the spi-cs-setup-ns to a value of 7. >> >> The sst26vf064b datasheet specifies just a minimum value for the >> "CE# Not Active Hold Time" and it advertises it to 5 ns. There's no >> maximum time specified. I determined experimentally that 5 ns for the >> spi-cs-setup-ns is not enough when the flash is operated close to its >> maximum frequency and tests showed that 7 ns is just fine, so set the >> spi-cs-setup-ns dt property to 7. >> >> With the increase of frequency the reads are now faster with ~37%. >> >> Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com> >> --- >> arch/arm/boot/dts/at91-sama5d27_wlsom1.dtsi | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/arch/arm/boot/dts/at91-sama5d27_wlsom1.dtsi >> b/arch/arm/boot/dts/at91-sama5d27_wlsom1.dtsi >> index 83bcf9fe0152..20caf40b4755 100644 >> --- a/arch/arm/boot/dts/at91-sama5d27_wlsom1.dtsi >> +++ b/arch/arm/boot/dts/at91-sama5d27_wlsom1.dtsi >> @@ -220,7 +220,8 @@ qspi1_flash: flash@0 { >> #size-cells = <1>; >> compatible = "jedec,spi-nor"; >> reg = <0>; >> - spi-max-frequency = <80000000>; >> + spi-max-frequency = <104000000>; >> + spi-cs-setup-ns = /bits/ 16 <7>; > > Following the different changes that happened to this property after > this post, am I right saying that this must now be changed to: > > spi-cs-setup-delay-ns = <7>; > > ? > Yes, that should do it. I'm amending the series right now. Can you do a little test on your side so that we make sure everything is in place? After the update, something like that should be run on any board (maybe wlsom1-ek?): #!/bin/sh dd if=/dev/urandom of=./qspi_test bs=1M count=6 mtd_debug write /dev/mtd5 0 6291456 qspi_test mtd_debug erase /dev/mtd5 0 6291456 mtd_debug read /dev/mtd5 0 6291456 qspi_read hexdump qspi_read mtd_debug write /dev/mtd5 0 6291456 qspi_test mtd_debug read /dev/mtd5 0 6291456 qspi_read sha1sum qspi_test qspi_read brb, ta
diff --git a/arch/arm/boot/dts/at91-sama5d27_wlsom1.dtsi b/arch/arm/boot/dts/at91-sama5d27_wlsom1.dtsi index 83bcf9fe0152..20caf40b4755 100644 --- a/arch/arm/boot/dts/at91-sama5d27_wlsom1.dtsi +++ b/arch/arm/boot/dts/at91-sama5d27_wlsom1.dtsi @@ -220,7 +220,8 @@ qspi1_flash: flash@0 { #size-cells = <1>; compatible = "jedec,spi-nor"; reg = <0>; - spi-max-frequency = <80000000>; + spi-max-frequency = <104000000>; + spi-cs-setup-ns = /bits/ 16 <7>; spi-rx-bus-width = <4>; spi-tx-bus-width = <4>; m25p,fast-read;
sama5d27-wlsom1 populates an sst26vf064b SPI NOR flash. Its maximum operating frequency for 2.7-3.6V is 104 MHz. As the flash is operated at 3.3V, increase its maximum supported frequency to 104MHz. The increasing of the spi-max-frequency value requires the setting of the "CE# Not Active Hold Time", thus set the spi-cs-setup-ns to a value of 7. The sst26vf064b datasheet specifies just a minimum value for the "CE# Not Active Hold Time" and it advertises it to 5 ns. There's no maximum time specified. I determined experimentally that 5 ns for the spi-cs-setup-ns is not enough when the flash is operated close to its maximum frequency and tests showed that 7 ns is just fine, so set the spi-cs-setup-ns dt property to 7. With the increase of frequency the reads are now faster with ~37%. Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com> --- arch/arm/boot/dts/at91-sama5d27_wlsom1.dtsi | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)