firmware: tegra: bpmp: Add tegra_bpmp_get_with_id() function

Some device tree bindings need to specify a parameter along with a BPMP
phandle reference to designate the ID associated with a given controller
that needs to interoperate with BPMP. Typically this is specified as an
extra cell in the nvidia,bpmp property, so add a helper to parse this ID
while resolving the phandle reference.

Signed-off-by: Thierry Reding <treding@nvidia.com>

Author: thierryreding

drivers/firmware/tegra/bpmp.c

@@ -32,6 +32,40 @@ channel_to_ops(struct tegra_bpmp_channel *channel)
 	return bpmp->soc->ops;
 }
 
+struct tegra_bpmp *tegra_bpmp_get_with_id(struct device *dev, unsigned int *id)
+{
+	struct platform_device *pdev;
+	struct of_phandle_args args;
+	struct tegra_bpmp *bpmp;
+	int err;
+
+	err = __of_parse_phandle_with_args(dev->of_node, "nvidia,bpmp", NULL,
+					   1, 0, &args);
+	if (err < 0)
+		return ERR_PTR(err);
+
+	pdev = of_find_device_by_node(args.np);
+	if (!pdev) {
+		bpmp = ERR_PTR(-ENODEV);
+		goto put;
+	}
+
+	bpmp = platform_get_drvdata(pdev);
+	if (!bpmp) {
+		bpmp = ERR_PTR(-EPROBE_DEFER);
+		put_device(&pdev->dev);
+		goto put;
+	}
+
+	if (id)
+		*id = args.args[0];
+
+put:
+	of_node_put(args.np);
+	return bpmp;
+}
+EXPORT_SYMBOL_GPL(tegra_bpmp_get_with_id);
+
 struct tegra_bpmp *tegra_bpmp_get(struct device *dev)
 {
 	struct platform_device *pdev;

include/soc/tegra/bpmp.h

@@ -127,6 +127,7 @@ struct tegra_bpmp_message {
 
 #if IS_ENABLED(CONFIG_TEGRA_BPMP)
 struct tegra_bpmp *tegra_bpmp_get(struct device *dev);
+struct tegra_bpmp *tegra_bpmp_get_with_id(struct device *dev, unsigned int *id);
 void tegra_bpmp_put(struct tegra_bpmp *bpmp);
 int tegra_bpmp_transfer_atomic(struct tegra_bpmp *bpmp,
 			       struct tegra_bpmp_message *msg);
@@ -145,6 +146,13 @@ static inline struct tegra_bpmp *tegra_bpmp_get(struct device *dev)
 {
 	return ERR_PTR(-ENOTSUPP);
 }
+
+static inline struct tegra_bpmp *tegra_bpmp_get_with_id(struct device *dev,
+							unsigned int *id)
+{
+	return ERR_PTR(-ENODEV);
+}
+
 static inline void tegra_bpmp_put(struct tegra_bpmp *bpmp)
 {
 }