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| author | Tudor Ambarus <tudor.ambarus@linaro.org> | 2023-03-28 13:15:15 +0300 |
|---|---|---|
| committer | Nicolas Ferre <nicolas.ferre@microchip.com> | 2023-03-30 22:20:59 +0300 |
| commit | 09ce8651229bb2d8e10ce0499e07da6f9bfaf5d8 (patch) | |
| tree | de60881f199d9af6ea652cd2b0fe3f6f0324ba86 /arch/arm/boot | |
| parent | 417e58ea41abe4c7f8be22ab5034b5e11f952240 (diff) | |
| download | linux-09ce8651229bb2d8e10ce0499e07da6f9bfaf5d8.tar.xz | |
ARM: dts: at91-sama5d27_som1: Set sst26vf064b SPI NOR flash at its maximum frequency
sama5d27-som1 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@linaro.org>
Link: https://lore.kernel.org/r/20230328101517.1595738-3-tudor.ambarus@linaro.org
Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Diffstat (limited to 'arch/arm/boot')
| -rw-r--r-- | arch/arm/boot/dts/at91-sama5d27_som1.dtsi | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/arm/boot/dts/at91-sama5d27_som1.dtsi b/arch/arm/boot/dts/at91-sama5d27_som1.dtsi index 8aa9e8dea337..95ecb7d040a8 100644 --- a/arch/arm/boot/dts/at91-sama5d27_som1.dtsi +++ b/arch/arm/boot/dts/at91-sama5d27_som1.dtsi @@ -43,7 +43,8 @@ #size-cells = <1>; compatible = "jedec,spi-nor"; reg = <0>; - spi-max-frequency = <80000000>; + spi-max-frequency = <104000000>; + spi-cs-setup-ns = <7>; spi-tx-bus-width = <4>; spi-rx-bus-width = <4>; m25p,fast-read; |