[PATCH 09/13] pci: dwc: pcie-kirin: allow to optionally require a regulator

[Mauro Carvalho Chehab <mchehab+huawei@kernel.org>]

On Hikey 970, there's a power supply controlled by Hi6421v600
regulator that turns on the PCI devices on the board. Without
that, no PCI hardware would work.

As this is device-dependent, such regulator line should be
optional.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
---
 drivers/pci/controller/dwc/pcie-kirin.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/pci/controller/dwc/pcie-kirin.c b/drivers/pci/controller/dwc/pcie-kirin.c
index 2bce6e3750d4..42aea34dff4d 100644
--- a/drivers/pci/controller/dwc/pcie-kirin.c
+++ b/drivers/pci/controller/dwc/pcie-kirin.c
@@ -22,6 +22,7 @@
 #include <linux/pci_regs.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
 #include <linux/resource.h>
 #include <linux/types.h>
 #include "pcie-designware.h"
@@ -295,6 +296,22 @@ static void kirin970_pcie_set_eyeparam(struct kirin_pcie *kirin_pcie)
 static long kirin_common_pcie_get_resource(struct kirin_pcie *kirin_pcie,
 					   struct platform_device *pdev)
 {
+	struct device *dev = &pdev->dev;
+	struct regulator *reg;
+	int ret;
+
+	reg = devm_regulator_get_optional(dev, "pci");
+	if (IS_ERR_OR_NULL(reg)) {
+		if (PTR_ERR(reg) == -EPROBE_DEFER)
+		    return PTR_ERR(reg);
+	} else {
+		ret = regulator_enable(reg);
+		if (ret) {
+			dev_err(dev, "Failed to enable regulator\n");
+			return ret;
+		}
+	}
+
 	kirin_pcie->apb_base = devm_platform_ioremap_resource_byname(pdev,
 								     "apb");
 	if (IS_ERR(kirin_pcie->apb_base))
-- 
2.29.2