[PATCH AUTOSEL 4.4 22/33] usb: ohci: Default to per-port over-current protection

Sasha Levin
2020-10-18T19:29:47Z

From: Hamish Martin <hamish.martin@alliedtelesis.co.nz>

[ Upstream commit b77d2a0a223bc139ee8904991b2922d215d02636 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/usb/host/ohci-hcd.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/host/ohci-hcd.c b/drivers/usb/host/ohci-hcd.c
index 27bd3e49fe8e3..07d76d9d4ce1b 100644
--- a/drivers/usb/host/ohci-hcd.c
+++ b/drivers/usb/host/ohci-hcd.c
@@ -663,20 +663,24 @@ 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);
--
2.25.1