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author | 2022-06-07 10:20:04 +0800 | |
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committer | 2022-06-10 11:21:27 +0200 | |
commit | 3497b9a5c8c3d4efaa15ab542cc6a774b0e0a7c6 (patch) | |
tree | 0e124ed55375f699e204ae0d6a7ab027beeb116a /drivers/usb/host | |
parent | usb: cdns3: fix random warning message when driver load (diff) | |
download | linux-3497b9a5c8c3d4efaa15ab542cc6a774b0e0a7c6.tar.gz linux-3497b9a5c8c3d4efaa15ab542cc6a774b0e0a7c6.tar.bz2 linux-3497b9a5c8c3d4efaa15ab542cc6a774b0e0a7c6.zip |
usb: dwc3: add power down scale setting
Some SoC(e.g NXP imx8MQ) may have a wrong default power down scale
setting so need init it to be the correct value, the power down
scale setting description in DWC3 databook:
Power Down Scale (PwrDnScale)
The USB3 suspend_clk input replaces pipe3_rx_pclk as a clock source to
a small part of the USB3 core that operates when the SS PHY is in its
lowest power (P3) state, and therefore does not provide a clock.
The Power Down Scale field specifies how many suspend_clk periods fit
into a 16 kHz clock period. When performing the division, round up the
remainder.
For example, when using an 8-bit/16-bit/32-bit PHY and 25-MHz Suspend
clock,
Power Down Scale = 25000 kHz/16 kHz = 13'd1563 (rounder up)
So use the suspend clock rate to calculate it.
Reviewed-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Signed-off-by: Li Jun <jun.li@nxp.com>
Link: https://lore.kernel.org/r/1654568404-3461-1-git-send-email-jun.li@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/host')
0 files changed, 0 insertions, 0 deletions