diff options
author | Douglas Anderson <dianders@chromium.org> | 2016-01-28 18:20:01 -0800 |
---|---|---|
committer | Felipe Balbi <balbi@kernel.org> | 2016-03-04 15:14:42 +0200 |
commit | 9ed04d976146cf10dfa4c71171434af7c0348747 (patch) | |
tree | d9fbca7deecc566c39216da85fde2dfffd08f937 /drivers/usb | |
parent | 8add17cf8e4c55c8c4342ed42c8cdc1649ce0ab8 (diff) |
usb: dwc2: host: Properly set the HFIR
According to the most up to date version of the dwc2 databook, the FRINT
field of the HFIR register should be programmed to:
* 125 us * (PHY clock freq for HS) - 1
* 1000 us * (PHY clock freq for FS/LS) - 1
This is opposed to older versions of the doc that claimed it should be:
* 125 us * (PHY clock freq for HS)
* 1000 us * (PHY clock freq for FS/LS)
In case you didn't spot it, the difference is the "- 1".
Let's add the "- 1" to match the newest user manual. It's presumed that
the "- 1" should have always been there and that this was always a
documentation error. If some hardware needs the "- 1" and other
hardware doesn't, we'll have to add a configuration parameter for it in
the future.
I checked things before and after this patch on rk3288 using a Total
Phase Beagle 5000 analyzer.
Before this patch, a low speed mouse shows constant Frame Timing Jitter
errors. After this patch errors have gone away.
Before this patch SOF packets move forward about 1 us per 4 ms. After
this patch the SOF packets move backward about 1 us per 255 ms. Some
specific SOF timestamps from the analyzer are below.
Before:
6.603.790
6.603.916
6.604.041
6.604.166
...
6.607.541
6.607.667
6.607.792
6.607.917
...
6.611.417
6.611.543
6.611.668
6.611.793
After:
6.215.159
6.215.284
6.215.408
6.215.533
6.215.658
...
6.470.658
6.470.783
6.470.907
...
6.726.032
6.726.157
6.725.281
6.725.406
Acked-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
Diffstat (limited to 'drivers/usb')
-rw-r--r-- | drivers/usb/dwc2/core.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/usb/dwc2/core.c b/drivers/usb/dwc2/core.c index bf5e3d0e3b49..26518eea1819 100644 --- a/drivers/usb/dwc2/core.c +++ b/drivers/usb/dwc2/core.c @@ -2245,10 +2245,10 @@ u32 dwc2_calc_frame_interval(struct dwc2_hsotg *hsotg) if ((hprt0 & HPRT0_SPD_MASK) >> HPRT0_SPD_SHIFT == HPRT0_SPD_HIGH_SPEED) /* High speed case */ - return 125 * clock; + return 125 * clock - 1; else /* FS/LS case */ - return 1000 * clock; + return 1000 * clock - 1; } /** |