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i2c: mux: Propagate firmware nodes to channel adapters

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Device Tree channel nodes are associated with the adapters created by
i2c-mux, but equivalent firmware-node descriptions are not.

Use generic firmware-node operations for the existing channel lookup
and associate the returned node with the adapter. Do not restrict the
lookup by firmware-node type, so Device Tree, software nodes, and ACPI
descriptions all follow the same property traversal. The existing
acpi_preset_companion() call remains in place for the standard ACPI
channel association.

Keep a separate reference to the node returned by the generic lookup
because acpi_preset_companion() may replace the device's primary
firmware node. Release the saved reference after adapter deletion.

Signed-off-by: Ahmad Byagowi <ahmadexp@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Acked-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://patch.msgid.link/00b33b4b352848ff87dd9089190b35d8732676f3.1788623619.git.ahmadexp@gmail.com
This commit is contained in:
Ahmad Byagowi 2026-09-07 23:26:23 -07:00 committed by Andi Shyti
parent ff9abb5161
commit 25083d5c01
No known key found for this signature in database
GPG Key ID: DA78056626D32D6E
1 changed files with 22 additions and 24 deletions
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46
drivers/i2c/i2c-mux.c
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@ -24,7 +24,7 @@
#include <linux/i2c-mux.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/property.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
@ -33,6 +33,7 @@ struct i2c_mux_priv {
struct i2c_adapter adap;
struct i2c_algorithm algo;
struct i2c_mux_core *muxc;
struct fwnode_handle *channel_node;
u32 chan_id;
};
@ -264,48 +265,48 @@ static const struct i2c_lock_operations i2c_parent_lock_ops = {
.unlock_bus = i2c_parent_unlock_bus,
};
static struct device_node *
static struct fwnode_handle *
i2c_mux_get_channel_node(struct i2c_mux_core *muxc, u32 chan_id)
{
struct device_node *dev_node;
struct device_node *mux_node;
struct device_node *child;
struct fwnode_handle *dev_node;
struct fwnode_handle *mux_node;
struct fwnode_handle *child;
u32 reg;
int ret;
dev_node = dev_of_node(muxc->dev);
dev_node = dev_fwnode(muxc->dev);
if (!dev_node)
return NULL;
if (muxc->arbitrator)
mux_node = of_get_child_by_name(dev_node, "i2c-arb");
mux_node = fwnode_get_named_child_node(dev_node, "i2c-arb");
else if (muxc->gate)
mux_node = of_get_child_by_name(dev_node, "i2c-gate");
mux_node = fwnode_get_named_child_node(dev_node, "i2c-gate");
else
mux_node = of_get_child_by_name(dev_node, "i2c-mux");
mux_node = fwnode_get_named_child_node(dev_node, "i2c-mux");
if (mux_node) {
/* A "reg" property indicates an old-style DT entry */
if (!of_property_read_u32(mux_node, "reg", &reg)) {
of_node_put(mux_node);
/* A "reg" property indicates an old-style firmware entry. */
if (!fwnode_property_read_u32(mux_node, "reg", &reg)) {
fwnode_handle_put(mux_node);
mux_node = NULL;
}
}
if (!mux_node)
mux_node = of_node_get(dev_node);
mux_node = fwnode_handle_get(dev_node);
else if (muxc->arbitrator || muxc->gate)
return mux_node;
for_each_child_of_node(mux_node, child) {
ret = of_property_read_u32(child, "reg", &reg);
fwnode_for_each_child_node(mux_node, child) {
ret = fwnode_property_read_u32(child, "reg", &reg);
if (ret)
continue;
if (chan_id == reg)
break;
}
of_node_put(mux_node);
fwnode_handle_put(mux_node);
return child;
}
@ -368,11 +369,9 @@ int i2c_mux_add_adapter(struct i2c_mux_core *muxc,
else
priv->adap.lock_ops = &i2c_parent_lock_ops;
/*
* Try to populate the mux adapter's of_node, expands to
* nothing if !CONFIG_OF.
*/
priv->adap.dev.of_node = i2c_mux_get_channel_node(muxc, chan_id);
/* Associate the mux adapter with its channel firmware node. */
priv->channel_node = i2c_mux_get_channel_node(muxc, chan_id);
device_set_node(&priv->adap.dev, priv->channel_node);
/*
* Associate the mux channel with an ACPI node.
@ -416,7 +415,7 @@ int i2c_mux_add_adapter(struct i2c_mux_core *muxc,
return 0;
err_free_priv:
of_node_put(priv->adap.dev.of_node);
fwnode_handle_put(priv->channel_node);
kfree(priv);
return ret;
}
@ -429,7 +428,6 @@ void i2c_mux_del_adapters(struct i2c_mux_core *muxc)
while (muxc->num_adapters) {
struct i2c_adapter *adap = muxc->adapter[--muxc->num_adapters];
struct i2c_mux_priv *priv = adap->algo_data;
struct device_node *np = adap->dev.of_node;
muxc->adapter[muxc->num_adapters] = NULL;
@ -439,7 +437,7 @@ void i2c_mux_del_adapters(struct i2c_mux_core *muxc)
sysfs_remove_link(&priv->adap.dev.kobj, "mux_device");
i2c_del_adapter(adap);
of_node_put(np);
fwnode_handle_put(priv->channel_node);
kfree(priv);
}
}