[PATCH v1 2/2] PCI: j721e: Add support for optional regulator supplies

[Vitor Soares <ivitro@gmail.com>]

From: Vitor Soares <vitor.soares@toradex.com>

Some boards require external regulators to power PCIe endpoints.
Add support for optional 1.5V, 3.3V, and 12V supplies, which may be
defined in the device tree as vpcie1v5-supply, vpcie3v3-supply, and
vpcie12v-supply.

Use devm_regulator_get_enable_optional() to obtain and enable each
supply, so it will be automatically disabled when the driver is
removed.

Signed-off-by: Vitor Soares <vitor.soares@toradex.com>
---
 drivers/pci/controller/cadence/pci-j721e.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/pci/controller/cadence/pci-j721e.c b/drivers/pci/controller/cadence/pci-j721e.c
index 5bc5ab20aa6d..f29ce2aef04e 100644
--- a/drivers/pci/controller/cadence/pci-j721e.c
+++ b/drivers/pci/controller/cadence/pci-j721e.c
@@ -21,6 +21,7 @@
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
 
 #include "../../pci.h"
 #include "pcie-cadence.h"
@@ -467,6 +468,10 @@ static const struct of_device_id of_j721e_pcie_match[] = {
 };
 MODULE_DEVICE_TABLE(of, of_j721e_pcie_match);
 
+static const char * const j721e_pcie_supplies[] = {
+	"vpcie12v", "vpcie3v3", "vpcie1v5"
+};
+
 static int j721e_pcie_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -480,6 +485,7 @@ static int j721e_pcie_probe(struct platform_device *pdev)
 	struct gpio_desc *gpiod;
 	void __iomem *base;
 	struct clk *clk;
+	unsigned int i;
 	u32 num_lanes;
 	u32 mode;
 	int ret;
@@ -565,6 +571,13 @@ static int j721e_pcie_probe(struct platform_device *pdev)
 	if (irq < 0)
 		return irq;
 
+	for (i = 0; i < ARRAY_SIZE(j721e_pcie_supplies); i++) {
+		ret = devm_regulator_get_enable_optional(dev, j721e_pcie_supplies[i]);
+		if (ret < 0 && ret != -ENODEV)
+			return dev_err_probe(dev, ret, "can't enable regulator %s\n",
+					     j721e_pcie_supplies[i]);
+	}
+
 	dev_set_drvdata(dev, pcie);
 	pm_runtime_enable(dev);
 	ret = pm_runtime_get_sync(dev);
-- 
2.51.0