[PATCH v1 4/4] PCI: brcmstb: Do not turn off WOL regulators on suspend

[Jim Quinlan <jim2101024@gmail.com>]

If any downstream device can be a wakeup device, do not turn off the
regulators as the device will need them on.

Link: https://lore.kernel.org/r/20220106160332.2143-8-jim2101024@gmail.com
Signed-off-by: Jim Quinlan <jim2101024@gmail.com>
---
 drivers/pci/controller/pcie-brcmstb.c | 53 ++++++++++++++++++++++-----
 1 file changed, 44 insertions(+), 9 deletions(-)

diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index a86bf502a265..d417dd366490 100644
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c
@@ -333,6 +333,7 @@ struct brcm_pcie {
 	void			(*bridge_sw_init_set)(struct brcm_pcie *pcie, u32 val);
 	bool			refusal_mode;
 	struct subdev_regulators *sr;
+	bool			ep_wakeup_capable;
 };
 
 static inline bool is_bmips(const struct brcm_pcie *pcie)
@@ -1350,9 +1351,21 @@ static void brcm_pcie_turn_off(struct brcm_pcie *pcie)
 	pcie->bridge_sw_init_set(pcie, 1);
 }
 
+static int pci_dev_may_wakeup(struct pci_dev *dev, void *data)
+{
+	bool *ret = data;
+
+	if (device_may_wakeup(&dev->dev)) {
+		*ret = true;
+		dev_info(&dev->dev, "disable cancelled for wake-up device\n");
+	}
+	return (int) *ret;
+}
+
 static int brcm_pcie_suspend(struct device *dev)
 {
 	struct brcm_pcie *pcie = dev_get_drvdata(dev);
+	struct pci_host_bridge *bridge = pci_host_bridge_from_priv(pcie);
 	int ret;
 
 	brcm_pcie_turn_off(pcie);
@@ -1371,11 +1384,22 @@ static int brcm_pcie_suspend(struct device *dev)
 	}
 
 	if (pcie->sr) {
-		ret = regulator_bulk_disable(pcie->sr->num_supplies, pcie->sr->supplies);
-		if (ret) {
-			dev_err(dev, "Could not turn off regulators\n");
-			reset_control_reset(pcie->rescal);
-			return ret;
+		/*
+		 * Now turn off the regulators, but if at least one
+		 * downstream device is enabled as a wake-up source, do not
+		 * turn off regulators.
+		 */
+		pcie->ep_wakeup_capable = false;
+		pci_walk_bus(bridge->bus, pci_dev_may_wakeup,
+			     &pcie->ep_wakeup_capable);
+		if (!pcie->ep_wakeup_capable) {
+			ret = regulator_bulk_disable(pcie->sr->num_supplies,
+						     pcie->sr->supplies);
+			if (ret) {
+				dev_err(dev, "Could not turn off regulators\n");
+				reset_control_reset(pcie->rescal);
+				return ret;
+			}
 		}
 	}
 	clk_disable_unprepare(pcie->clk);
@@ -1396,10 +1420,21 @@ static int brcm_pcie_resume(struct device *dev)
 		return ret;
 
 	if (pcie->sr) {
-		ret = regulator_bulk_enable(pcie->sr->num_supplies, pcie->sr->supplies);
-		if (ret) {
-			dev_err(dev, "Could not turn on regulators\n");
-			goto err_disable_clk;
+		if (pcie->ep_wakeup_capable) {
+			/*
+			 * We are resuming from a suspend.  In the suspend we
+			 * did not disable the power supplies, so there is
+			 * no need to enable them (and falsely increase their
+			 * usage count).
+			 */
+			pcie->ep_wakeup_capable = false;
+		} else {
+			ret = regulator_bulk_enable(pcie->sr->num_supplies,
+						    pcie->sr->supplies);
+			if (ret) {
+				dev_err(dev, "Could not turn on regulators\n");
+				goto err_disable_clk;
+			}
 		}
 	}
 
-- 
2.17.1