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 reg property is provided, use that to
identify the address space for this mux. If not provided fallback to
using the parent device as a regmap provider.

While here use dev_err_probe() in the error path to prevent printing
a message on probe defer which now can happen in extra ways.

Signed-off-by: Andrew Davis <afd@ti.com>
Reviewed-by: Nishanth Menon <nm@ti.com>
Acked-by: Peter Rosin <peda@axentia.se>
Link: https://lore.kernel.org/r/20240104154552.17852-1-afd@ti.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/mux/mmio.c b/drivers/mux/mmio.c
index fd1d121a584ba211991f2ec10aef39c5bba6a339..30a952c34365f4957a9fdc2acef7009673200898 100644 (file)
--- a/drivers/mux/mmio.c
+++ b/drivers/mux/mmio.c
@@ -44,15 +44,20 @@ 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);
-       if (IS_ERR(regmap)) {
-               ret = PTR_ERR(regmap);
-               dev_err(dev, "failed to get regmap: %d\n", ret);
-               return ret;
+       } else {
+               regmap = device_node_to_regmap(np);
+               /* Fallback to checking the parent node on "real" errors. */
+               if (IS_ERR(regmap) && regmap != ERR_PTR(-EPROBE_DEFER)) {
+                       regmap = dev_get_regmap(dev->parent, NULL);
+                       if (!regmap)
+                               regmap = ERR_PTR(-ENODEV);
+               }
        }
+       if (IS_ERR(regmap))
+               return dev_err_probe(dev, PTR_ERR(regmap),
+                                    "failed to get regmap\n");
 
        ret = of_property_count_u32_elems(np, "mux-reg-masks");
        if (ret == 0 || ret % 2)