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usb: ohci: Default to per-port over-current protection 

Some integrated OHCI controller hubs do not expose all ports of the hub
to pins on the SoC. In some cases the unconnected ports generate
spurious over-current events. For example the Broadcom 56060/Ranger 2 SoC
contains a nominally 3 port hub but only the first port is wired.

Default behaviour for ohci-platform driver is to use global over-current
protection mode (AKA "ganged"). This leads to the spurious over-current
events affecting all ports in the hub.

We now alter the default to use per-port over-current protection.

This patch results in the following configuration changes depending
on quirks:
- For quirk OHCI_QUIRK_SUPERIO no changes. These systems remain set up
  for ganged power switching and no over-current protection.
- For quirk OHCI_QUIRK_AMD756 or OHCI_QUIRK_HUB_POWER power switching
  remains at none, while over-current protection is now guaranteed to be
  set to per-port rather than the previous behaviour where it was either
  none or global over-current protection depending on the value at
  function entry.

Suggested-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Hamish Martin <hamish.martin@alliedtelesis.co.nz>
Link: https://lore.kernel.org/r/20200910212512.16670-1-hamish.martin@alliedtelesis.co.nz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Hamish Martin 2020-09-11 09:25:11 +12:00 committed by Greg Kroah-Hartman
parent e03b9dfb67
commit b77d2a0a22
1 changed files with 10 additions and 6 deletions
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16
drivers/usb/host/ohci-hcd.c
View File

@ -673,20 +673,24 @@ static int ohci_run (struct ohci_hcd *ohci)
/* handle root hub init quirks ... */
val = roothub_a (ohci);
val &= ~(RH_A_PSM | RH_A_OCPM);
/* Configure for per-port over-current protection by default */
val &= ~RH_A_NOCP;
val |= RH_A_OCPM;
if (ohci->flags & OHCI_QUIRK_SUPERIO) {
/* NSC 87560 and maybe others */
/* NSC 87560 and maybe others.
* Ganged power switching, no over-current protection.
*/
val |= RH_A_NOCP;
val &= ~(RH_A_POTPGT | RH_A_NPS);
ohci_writel (ohci, val, &ohci->regs->roothub.a);
val &= ~(RH_A_POTPGT | RH_A_NPS | RH_A_PSM | RH_A_OCPM);
} else if ((ohci->flags & OHCI_QUIRK_AMD756) ||
(ohci->flags & OHCI_QUIRK_HUB_POWER)) {
/* hub power always on; required for AMD-756 and some
* Mac platforms. ganged overcurrent reporting, if any.
* Mac platforms.
*/
val |= RH_A_NPS;
ohci_writel (ohci, val, &ohci->regs->roothub.a);
}
ohci_writel(ohci, val, &ohci->regs->roothub.a);
ohci_writel (ohci, RH_HS_LPSC, &ohci->regs->roothub.status);
ohci_writel (ohci, (val & RH_A_NPS) ? 0 : RH_B_PPCM,
&ohci->regs->roothub.b);