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author | Sascha Hauer <s.hauer@pengutronix.de> | 2019-10-15 10:55:58 +0200 |
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committer | Sascha Hauer <s.hauer@pengutronix.de> | 2019-10-15 10:55:58 +0200 |
commit | 2036f2866753a28b2783ad6dc78a40ca5345e6d8 (patch) | |
tree | 468b1c17b06a2377c5f8e6d711d8f3187f60667f /dts/Bindings/net/micrel-ksz90x1.txt | |
parent | 785f926d4527184194b6424bc39ce367e2cea7d8 (diff) | |
download | barebox-2036f2866753a28b2783ad6dc78a40ca5345e6d8.tar.gz barebox-2036f2866753a28b2783ad6dc78a40ca5345e6d8.tar.xz |
dts: update to v5.4-rc1
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'dts/Bindings/net/micrel-ksz90x1.txt')
-rw-r--r-- | dts/Bindings/net/micrel-ksz90x1.txt | 32 |
1 files changed, 30 insertions, 2 deletions
diff --git a/dts/Bindings/net/micrel-ksz90x1.txt b/dts/Bindings/net/micrel-ksz90x1.txt index 5100358177..b921731cd9 100644 --- a/dts/Bindings/net/micrel-ksz90x1.txt +++ b/dts/Bindings/net/micrel-ksz90x1.txt @@ -12,8 +12,36 @@ and therefore may overwrite them. KSZ9021: All skew control options are specified in picoseconds. The minimum - value is 0, the maximum value is 3000, and it is incremented by 200ps - steps. + value is 0, the maximum value is 3000, and it can be specified in 200ps + steps, *but* these values are in not fact what you get because this chip's + skew values actually increase in 120ps steps, starting from -840ps. The + incorrect values came from an error in the original KSZ9021 datasheet + before it was corrected in revision 1.2 (Feb 2014), but it is too late to + change the driver now because of the many existing device trees that have + been created using values that go up in increments of 200. + + The following table shows the actual skew delay you will get for each of the + possible devicetree values, and the number that will be programmed into the + corresponding pad skew register: + + Device Tree Value Delay Pad Skew Register Value + ----------------------------------------------------- + 0 -840ps 0000 + 200 -720ps 0001 + 400 -600ps 0010 + 600 -480ps 0011 + 800 -360ps 0100 + 1000 -240ps 0101 + 1200 -120ps 0110 + 1400 0ps 0111 + 1600 120ps 1000 + 1800 240ps 1001 + 2000 360ps 1010 + 2200 480ps 1011 + 2400 600ps 1100 + 2600 720ps 1101 + 2800 840ps 1110 + 3000 960ps 1111 Optional properties: |