From 39c1f1bd8adf29840ef52225ce95f390e3d7b2cf Mon Sep 17 00:00:00 2001 From: Roger Pau Monne Date: Thu, 25 Mar 2021 10:09:47 +0100 Subject: pinctrl: intel: check REVID register value for device presence MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 --- drivers/pinctrl/intel/pinctrl-intel.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'drivers/pinctrl') diff --git a/drivers/pinctrl/intel/pinctrl-intel.c b/drivers/pinctrl/intel/pinctrl-intel.c index 7283203861ae..9f3361c13ded 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; -- cgit v1.2.3