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| author | Adrian Schmutzler <freifunk@adrianschmutzler.de> | 2020-02-27 11:55:36 +0100 |
|---|---|---|
| committer | Adrian Schmutzler <freifunk@adrianschmutzler.de> | 2020-02-27 12:14:09 +0100 |
| commit | ebc090e420d1fc3ed30fc9f0331ee95422c2bace (patch) | |
| tree | 48fd8b997020c7ecb15f8e00937a5c6087adac1e | |
| parent | 9de6bc872af50c80f0ba449422f413cfa613f7e5 (diff) | |
| download | upstream-ebc090e420d1fc3ed30fc9f0331ee95422c2bace.tar.gz upstream-ebc090e420d1fc3ed30fc9f0331ee95422c2bace.tar.bz2 upstream-ebc090e420d1fc3ed30fc9f0331ee95422c2bace.zip | |
ath79: reduce spi-max-frequency to 50 MHz
The introduction of ebf0d8dadeca ("ath79: add new ar934x spi driver")
made the SPI memory unusable on devices with very high spi-max-frequency
(104 MHz).
Here's how the actual clock is calculated: (AHB_CLK/((CLOCK_DIVIDER+1)*2))
where AHB_CLK is a fixed clock (e.g. 200MHz on AR9331) and CLOCK_DIVIDER
is the parameter we can set. Highest clock according to this formula is
AHB_CLK/2 (100MHz, but that didn't work in device tests).
The next possible value is AHB_CLK/4 (50MHz). Speeds between 50 MHz and
100 MHz will be rounded down, so using values higher than 50 MHz does
not provide any benefit.
Consequently, this patch reduces spi-max-frequency for all devices with
values higher than 50 MHz to 50 MHz (effectively, this only affects
devices with 104 MHz before this patch).
Tested on GL.inet GL-AR150:
Boot fails with 104 MHz but is successful with both 50 MHz and 80 MHz
(fast-read), where the latter two yield identical read speeds.
Fixes: ebf0d8dadeca ("ath79: add new ar934x spi driver")
Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
6 files changed, 6 insertions, 6 deletions
diff --git a/target/linux/ath79/dts/ar9330_glinet_gl-ar150.dts b/target/linux/ath79/dts/ar9330_glinet_gl-ar150.dts index 70754c905e..68e1995c76 100644 --- a/target/linux/ath79/dts/ar9330_glinet_gl-ar150.dts +++ b/target/linux/ath79/dts/ar9330_glinet_gl-ar150.dts @@ -86,7 +86,7 @@ flash@0 { compatible = "jedec,spi-nor"; - spi-max-frequency = <104000000>; + spi-max-frequency = <50000000>; reg = <0>; partitions { diff --git a/target/linux/ath79/dts/ar9330_pqi_air-pen.dts b/target/linux/ath79/dts/ar9330_pqi_air-pen.dts index 92484f9331..8537faa0f9 100644 --- a/target/linux/ath79/dts/ar9330_pqi_air-pen.dts +++ b/target/linux/ath79/dts/ar9330_pqi_air-pen.dts @@ -75,7 +75,7 @@ flash@0 { compatible = "jedec,spi-nor"; - spi-max-frequency = <104000000>; + spi-max-frequency = <50000000>; reg = <0>; partitions { diff --git a/target/linux/ath79/dts/ar9331_8dev_carambola2.dts b/target/linux/ath79/dts/ar9331_8dev_carambola2.dts index cc0320d652..ef244f0b55 100644 --- a/target/linux/ath79/dts/ar9331_8dev_carambola2.dts +++ b/target/linux/ath79/dts/ar9331_8dev_carambola2.dts @@ -73,7 +73,7 @@ flash@0 { compatible = "jedec,spi-nor"; - spi-max-frequency = <104000000>; + spi-max-frequency = <50000000>; reg = <0>; partitions { diff --git a/target/linux/ath79/dts/ar9331_embeddedwireless_dorin.dts b/target/linux/ath79/dts/ar9331_embeddedwireless_dorin.dts index 3489a972d4..4761b91093 100644 --- a/target/linux/ath79/dts/ar9331_embeddedwireless_dorin.dts +++ b/target/linux/ath79/dts/ar9331_embeddedwireless_dorin.dts @@ -68,7 +68,7 @@ flash@0 { compatible = "jedec,spi-nor"; - spi-max-frequency = <104000000>; + spi-max-frequency = <50000000>; reg = <0>; partitions { diff --git a/target/linux/ath79/dts/ar9331_tplink_tl-mr3020-v1.dts b/target/linux/ath79/dts/ar9331_tplink_tl-mr3020-v1.dts index 3cd5c130c8..97a058edf6 100644 --- a/target/linux/ath79/dts/ar9331_tplink_tl-mr3020-v1.dts +++ b/target/linux/ath79/dts/ar9331_tplink_tl-mr3020-v1.dts @@ -120,7 +120,7 @@ /* Spansion S25FL032PIF SPI flash */ flash@0 { compatible = "jedec,spi-nor"; - spi-max-frequency = <104000000>; + spi-max-frequency = <50000000>; reg = <0>; partitions { diff --git a/target/linux/ath79/dts/ar9331_tplink_tl-mr3040-v2.dts b/target/linux/ath79/dts/ar9331_tplink_tl-mr3040-v2.dts index e8a3dfbce7..5918e611dd 100644 --- a/target/linux/ath79/dts/ar9331_tplink_tl-mr3040-v2.dts +++ b/target/linux/ath79/dts/ar9331_tplink_tl-mr3040-v2.dts @@ -114,7 +114,7 @@ flash@0 { compatible = "jedec,spi-nor"; - spi-max-frequency = <104000000>; + spi-max-frequency = <50000000>; reg = <0>; partitions { |