From: Roger Pau Monne Date: Thu, 25 Mar 2021 09:09:47 +0000 (+0100) Subject: pinctrl: intel: check REVID register value for device presence X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=39c1f1bd8adf29840ef52225ce95f390e3d7b2cf;p=linux.git pinctrl: intel: check REVID register value for device presence Use the value read from the REVID register in order to check for the presence of the device. A read of all ones is treated as if the device is not present, and hence probing is ended. This fixes an issue when running as a Xen PVH dom0, where the ACPI DSDT table is provided unmodified to dom0 and hence contains the pinctrl devices, but the MMIO region(s) containing the device registers might not be mapped in the guest physical memory map if such region(s) are not exposed on a PCI device BAR or marked as reserved in the host memory map. Fixes: 91d898e51e60 ("pinctrl: intel: Convert capability list to features") Suggested-by: Andy Shevchenko Signed-off-by: Roger Pau Monné Signed-off-by: Andy Shevchenko --- diff --git a/drivers/pinctrl/intel/pinctrl-intel.c b/drivers/pinctrl/intel/pinctrl-intel.c index 7283203861aee..9f3361c13ded8 100644 --- a/drivers/pinctrl/intel/pinctrl-intel.c +++ b/drivers/pinctrl/intel/pinctrl-intel.c @@ -1493,8 +1493,13 @@ static int intel_pinctrl_probe(struct platform_device *pdev, if (IS_ERR(regs)) return PTR_ERR(regs); - /* Determine community features based on the revision */ + /* + * Determine community features based on the revision. + * A value of all ones means the device is not present. + */ value = readl(regs + REVID); + if (value == ~0u) + return -ENODEV; if (((value & REVID_MASK) >> REVID_SHIFT) >= 0x94) { community->features |= PINCTRL_FEATURE_DEBOUNCE; community->features |= PINCTRL_FEATURE_1K_PD;