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| author | Tudor Ambarus <tudor.ambarus@linaro.org> | 2023-03-28 13:15:16 +0300 |
|---|---|---|
| committer | Nicolas Ferre <nicolas.ferre@microchip.com> | 2023-03-30 22:20:59 +0300 |
| commit | 46a8a137d8f60929923a609cdddde06e7007b0df (patch) | |
| tree | 0617f766850175d0a1e484650d379b91e721b474 /arch/arm/boot | |
| parent | 09ce8651229bb2d8e10ce0499e07da6f9bfaf5d8 (diff) | |
| download | linux-46a8a137d8f60929923a609cdddde06e7007b0df.tar.xz | |
ARM: dts: at91: sama5d2_icp: Set sst26vf064b SPI NOR flash at its maximum frequency
sama5d2_icp 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>
Tested-by: Nicolas Ferre <nicolas.ferre@microchip.com> # on sama5d2 ICP
Link: https://lore.kernel.org/r/20230328101517.1595738-4-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-sama5d2_icp.dts | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/arm/boot/dts/at91-sama5d2_icp.dts b/arch/arm/boot/dts/at91-sama5d2_icp.dts index 1346b8f2b259..999adeca6f33 100644 --- a/arch/arm/boot/dts/at91-sama5d2_icp.dts +++ b/arch/arm/boot/dts/at91-sama5d2_icp.dts @@ -669,7 +669,8 @@ #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; |