[PATCH 2/2] PCI: rcar-host: add support for optional regulators

[Wolfram Sang]

The KingFisher board has regulators. They just need to be en-/disabled,
so we can leave the handling to devm.

Signed-off-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
---

Changes since RFC:
* add 12v regulator
* add comment about the order of enabling the regulators
* use a for-loop to iterate over the regulators

Sidenote: I tried to introduce 'devm_regulator_bulk_get_enable_optional'
to avoid the for-loop but that was a too intrusive change because all of
the regulator_bulk logic is designed to fail if something bad happens
somewhere.

 drivers/pci/controller/pcie-rcar-host.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/controller/pcie-rcar-host.c b/drivers/pci/controller/pcie-rcar-host.c
index e80e56b2a842..e86bf0f7729b 100644
--- a/drivers/pci/controller/pcie-rcar-host.c
+++ b/drivers/pci/controller/pcie-rcar-host.c
@@ -29,6 +29,7 @@
 #include <linux/phy/phy.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
+#include <linux/regulator/consumer.h>
 
 #include "pcie-rcar.h"
 
@@ -974,13 +975,18 @@ static const struct of_device_id rcar_pcie_of_match[] = {
 	{},
 };
 
+/* Design note 346 from Linear Technology says order is not important */
+static const char * const rcar_pcie_supplies[] = {
+	"vpcie12v", "vpcie3v3", "vpcie1v5"
+};
+
 static int rcar_pcie_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct rcar_pcie_host *host;
 	struct rcar_pcie *pcie;
 	u32 data;
-	int err;
+	int i, err;
 	struct pci_host_bridge *bridge;
 
 	bridge = devm_pci_alloc_host_bridge(dev, sizeof(*host));
@@ -992,6 +998,13 @@ static int rcar_pcie_probe(struct platform_device *pdev)
 	pcie->dev = dev;
 	platform_set_drvdata(pdev, host);
 
+	for (i = 0; i < ARRAY_SIZE(rcar_pcie_supplies); i++) {
+		err = devm_regulator_get_enable_optional(dev, rcar_pcie_supplies[i]);
+		if (err < 0 && err != -ENODEV)
+			dev_err_probe(dev, err, "error enabling regulator %s\n",
+				      rcar_pcie_supplies[i]);
+	}
+
 	pm_runtime_enable(pcie->dev);
 	err = pm_runtime_get_sync(pcie->dev);
 	if (err < 0) {
-- 
2.30.2