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Currently the reset-gpio DT property which controls the PCI bus device reset signal defaults to active-low reset sequence (L=reset state, H=operation state) plus the code in reset function isn't GPIO polarity aware - it doesn't matter if the defined reset-gpio is active-low or active-high, it will always result into active-low reset sequence. I've tried to fix it properly and change the reset-gpio reset sequence to be polarity-aware, but this patch has been accepted and then reverted as it has introduced few backward incompatible issues: 1. Some DTBs, for example, imx6qdl-sabresd, don't define reset-gpio polarity correctly: reset-gpio = <&gpio7 12 0>; which means that it's defined as active-high, but in reality it's active-low; thus it wouldn't work without a DTS fix. 2. The logic in the reset function is inverted: gpio_set_value_cansleep(imx6_pcie->reset_gpio, 0) msleep(100); gpio_set_value_cansleep(imx6_pcie->reset_gpio, 1); so even if some of the i.MX6 boards had reset-gpio polarity defined correctly in their DTSes, they would stop working. As we can't break old DTBs, we can't fix them, so we need to introduce this new DT reset-gpio-active-high boolean property so we can support boards with active-high reset sequence. This active-high reset sequence is for example needed on Apalis SoMs, where GPIO1_IO28, used to PCIe reset is not connected directly to PERST# PCIe signal, but it's ORed with RESETBMCU coming off the PMIC, and thus is inverted, active-high. Tested-by: Tim Harvey <tharvey@gateworks.com> # Gateworks Ventana boards (which have active-low PERST#) Signed-off-by: Petr Štetiar <ynezz@true.cz> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Lucas Stach <l.stach@pengutronix.de> Acked-by: Rob Herring <robh@kernel.org> |
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| .. | ||
| host | ||
| hotplug | ||
| pcie | ||
| access.c | ||
| ats.c | ||
| bus.c | ||
| host-bridge.c | ||
| hotplug-pci.c | ||
| htirq.c | ||
| iov.c | ||
| irq.c | ||
| Kconfig | ||
| Makefile | ||
| msi.c | ||
| of.c | ||
| pci-acpi.c | ||
| pci-driver.c | ||
| pci-label.c | ||
| pci-stub.c | ||
| pci-sysfs.c | ||
| pci.c | ||
| pci.h | ||
| probe.c | ||
| proc.c | ||
| quirks.c | ||
| remove.c | ||
| rom.c | ||
| search.c | ||
| setup-bus.c | ||
| setup-irq.c | ||
| setup-res.c | ||
| slot.c | ||
| syscall.c | ||
| vc.c | ||
| vpd.c | ||
| xen-pcifront.c | ||