[PATCH] pinctrl: intel: save HOSTSW_OWN register over suspend/resume

[Chris Chiu]

The touchpad in the Asus laptop model X540NA is unresponsive
after suspend/resume. The following error appears during resume:

i2c_hid i2c-ELAN1200:00: failed to reset device.

The problem here is that i2c_hid does not notice the interrupt
being generated at this point. Because the GPIO which connects
to touchpad interrupt is in ACPI mode after resume and no longer
work as IRQ.

Fix this by saving HOSTSW_OWN register during suspend and restore
them at resume.

Signed-off-by: Chris Chiu <chiu@xxxxxxxxxxxx>
---
 drivers/pinctrl/intel/pinctrl-intel.c | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/drivers/pinctrl/intel/pinctrl-intel.c b/drivers/pinctrl/intel/pinctrl-intel.c
index 6dc1096d3d34..eaafa0e534f3 100644
--- a/drivers/pinctrl/intel/pinctrl-intel.c
+++ b/drivers/pinctrl/intel/pinctrl-intel.c
@@ -83,6 +83,7 @@ struct intel_pad_context {
 
 struct intel_community_context {
 	u32 *intmask;
+	u32 *modemask;
 };
 
 struct intel_pinctrl_context {
@@ -1158,6 +1159,7 @@ static int intel_pinctrl_pm_init(struct intel_pinctrl *pctrl)
 	for (i = 0; i < pctrl->ncommunities; i++) {
 		struct intel_community *community = &pctrl->communities[i];
 		u32 *intmask;
+		u32 *modemask;
 
 		intmask = devm_kcalloc(pctrl->dev, community->ngpps,
 				       sizeof(*intmask), GFP_KERNEL);
@@ -1165,6 +1167,13 @@ static int intel_pinctrl_pm_init(struct intel_pinctrl *pctrl)
 			return -ENOMEM;
 
 		communities[i].intmask = intmask;
+
+		modemask = devm_kcalloc(pctrl->dev, community->ngpps,
+				       sizeof(*modemask), GFP_KERNEL);
+		if (!modemask)
+			return -ENOMEM;
+
+		communities[i].modemask = modemask;
 	}
 
 	pctrl->context.pads = pads;
@@ -1329,6 +1338,10 @@ int intel_pinctrl_suspend(struct device *dev)
 		base = community->regs + community->ie_offset;
 		for (gpp = 0; gpp < community->ngpps; gpp++)
 			communities[i].intmask[gpp] = readl(base + gpp * 4);
+
+		base = community->regs + community->hostown_offset;
+		for (gpp = 0; gpp < community->ngpps; gpp++)
+			communities[i].modemask[gpp] = readl(base + gpp * 4);
 	}
 
 	return 0;
@@ -1411,7 +1424,14 @@ int intel_pinctrl_resume(struct device *dev)
 		base = community->regs + community->ie_offset;
 		for (gpp = 0; gpp < community->ngpps; gpp++) {
 			writel(communities[i].intmask[gpp], base + gpp * 4);
-			dev_dbg(dev, "restored mask %d/%u %#08x\n", i, gpp,
+			dev_dbg(dev, "restored intmask %d/%u %#08x\n", i, gpp,
+				readl(base + gpp * 4));
+		}
+
+		base = community->regs + community->hostown_offset;
+		for (gpp = 0; gpp < community->ngpps; gpp++) {
+			writel(communities[i].modemask[gpp], base + gpp * 4);
+			dev_dbg(dev, "restored modemask %d/%u %#08x\n", i, gpp,
 				readl(base + gpp * 4));
 		}
 	}
-- 
2.11.0