linux-kernel - [RFC] mux: mmio: use reg property when parent device is not a syscon

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Date:   Mon, 24 Apr 2023 13:48:10 -0500
From:   Andrew Davis <afd@...com>
To:     Peter Rosin <peda@...ntia.se>, Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Nishanth Menon <nm@...com>,
        Vignesh Raghavendra <vigneshr@...com>
CC:     <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        Andrew Davis <afd@...com>
Subject: [RFC] mux: mmio: use reg property when parent device is not a syscon

The DT binding for the reg-mux compatible states it can be used when the
"parent device of mux controller is not syscon device". It also allows
for a reg property. When the parent device is indeed not a syscon device,
nor is it a regmap provider, we should fallback to using that reg
property to identify the address space to use for this mux.

Signed-off-by: Andrew Davis <afd@...com>
---
 drivers/mux/mmio.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/mux/mmio.c b/drivers/mux/mmio.c
index 44a7a0e885b8..42e00b9fd0a9 100644
--- a/drivers/mux/mmio.c
+++ b/drivers/mux/mmio.c
@@ -44,10 +44,13 @@ static int mux_mmio_probe(struct platform_device *pdev)
 	int ret;
 	int i;
 
-	if (of_device_is_compatible(np, "mmio-mux"))
+	if (of_device_is_compatible(np, "mmio-mux")) {
 		regmap = syscon_node_to_regmap(np->parent);
-	else
-		regmap = dev_get_regmap(dev->parent, NULL) ?: ERR_PTR(-ENODEV);
+	} else {
+		regmap = dev_get_regmap(dev->parent, NULL);
+		if (!regmap)
+			regmap = device_node_to_regmap(np) ?: ERR_PTR(-ENODEV);
+	}
 	if (IS_ERR(regmap)) {
 		ret = PTR_ERR(regmap);
 		dev_err(dev, "failed to get regmap: %d\n", ret);
-- 
2.39.2