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i2c: mux: reg: use device property accessors

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Convert the device-tree parsing path to the generic fwnode/device
property accessors so the driver can be probed on ACPI and swnode
platforms as well as OF. The helper is renamed from
i2c_mux_reg_probe_dt() to i2c_mux_reg_probe_fw() to reflect that.

Accessor translation:

  of_parse_phandle("i2c-parent") +
    of_find_i2c_adapter_by_node()    -> fwnode_find_reference() +
                                         i2c_find_adapter_by_fwnode()
  of_get_child_count()               -> device_get_child_node_count()
  of_property_read_bool()            -> device_property_read_bool()
  for_each_child_of_node()           -> device_for_each_child_node()
    of_property_read_u32("reg")        on ACPI device nodes:
                                         acpi_get_local_address()
                                       everything else (OF, swnode,
                                       ACPI data nodes):
                                         fwnode_property_read_u32()
  of_property_read_u32("idle-state") -> device_property_read_u32()

The child-node branch uses is_acpi_device_node() rather than
is_acpi_node(): the latter also matches ACPI data nodes (the
_DSD hierarchical-property children used by PRP0001-style
firmware), which have no ACPI handle and would make
acpi_get_local_address() fall back to evaluating _ADR against the
root namespace and return -ENODATA.  Routing data nodes through
fwnode_property_read_u32() instead lets them resolve the "reg"
property the same way OF and swnode children do.

Behavioural preservations (deliberate, to avoid regressing existing
users):

  - The three-way endian fallback is kept verbatim: an explicit
    "little-endian" property wins, then "big-endian", and otherwise
    the host's compile-time byte order. device_is_big_endian() is
    not used here because it ignores "little-endian" and introduces
    "native-endian" semantics, which would diverge from the binding.

  - The "if (!mux->data.reg)" guard around
    devm_platform_get_and_ioremap_resource() in probe() is kept.
    drivers/platform/mellanox/mlx-platform.c registers i2c-mux-reg
    platform_devices with no memory resource and supplies a
    pre-set .reg / .reg_size through struct
    i2c_mux_reg_platform_data; without the guard those
    registrations would fail in probe().

  - The "if (!mux->data.reg)" ioremap block (and the paired
    reg_size validation that depends on it) is hoisted above
    i2c_get_adapter(mux->data.parent), so the fwnode path
    preserves master's ordering of "ioremap before parent-adapter
    get".  For platdata users the validation runs from a slightly
    earlier position, but mux->data.reg_size is already set from
    platdata by then, so the order is functionally neutral.

The OF-only of_address_to_resource() translation in the old
probe_dt() is dropped because the same address is available from
the platform_device resource table on OF as well as ACPI, and the
existing fallback in probe() ioremaps it.

Acked-by: Peter Rosin <peda@lysator.liu.se>
Signed-off-by: Abdurrahman Hussain <abdurrahman@nexthop.ai>
Assisted-by: Claude-Code:claude-opus-4-7
Assisted-by: sashiko:gemini-3.1-pro-preview
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
This commit is contained in:
Abdurrahman Hussain
2026-05-19 14:18:50 -07:00
committed by Andi Shyti
parent 5351cf8e96
commit 3279986bfe
1 changed files with 38 additions and 52 deletions
Download Patch File Download Diff File Expand all files Collapse all files

90
drivers/i2c/muxes/i2c-mux-reg.c
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@@ -11,7 +11,6 @@
#include <linux/init.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/platform_data/i2c-mux-reg.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
@@ -75,37 +74,34 @@ static int i2c_mux_reg_deselect(struct i2c_mux_core *muxc, u32 chan)
return 0;
}
#ifdef CONFIG_OF
static int i2c_mux_reg_probe_dt(struct regmux *mux,
struct platform_device *pdev)
static int i2c_mux_reg_probe_fw(struct regmux *mux, struct device *dev)
{
struct device_node *np = pdev->dev.of_node;
struct device_node *adapter_np, *child;
struct fwnode_handle *fwnode, *child;
struct i2c_adapter *adapter;
struct resource res;
unsigned *values;
int i = 0;
int ret, i = 0;
if (!np)
if (!dev_fwnode(dev))
return -ENODEV;
adapter_np = of_parse_phandle(np, "i2c-parent", 0);
if (!adapter_np) {
dev_err(&pdev->dev, "Cannot parse i2c-parent\n");
fwnode = fwnode_find_reference(dev_fwnode(dev), "i2c-parent", 0);
if (IS_ERR(fwnode)) {
dev_err(dev, "missing 'i2c-parent' property\n");
return -ENODEV;
}
adapter = of_find_i2c_adapter_by_node(adapter_np);
of_node_put(adapter_np);
adapter = i2c_find_adapter_by_fwnode(fwnode);
fwnode_handle_put(fwnode);
if (!adapter)
return -EPROBE_DEFER;
mux->data.parent = i2c_adapter_id(adapter);
put_device(&adapter->dev);
mux->data.n_values = of_get_child_count(np);
if (of_property_read_bool(np, "little-endian")) {
mux->data.n_values = device_get_child_node_count(dev);
if (device_property_read_bool(dev, "little-endian")) {
mux->data.little_endian = true;
} else if (of_property_read_bool(np, "big-endian")) {
} else if (device_property_read_bool(dev, "big-endian")) {
mux->data.little_endian = false;
} else {
#if defined(__BYTE_ORDER) ? __BYTE_ORDER == __LITTLE_ENDIAN : \
@@ -118,40 +114,35 @@ static int i2c_mux_reg_probe_dt(struct regmux *mux,
#error Endianness not defined?
#endif
}
mux->data.write_only = of_property_read_bool(np, "write-only");
mux->data.write_only = device_property_read_bool(dev, "write-only");
values = devm_kcalloc(&pdev->dev,
mux->data.n_values, sizeof(*mux->data.values),
values = devm_kcalloc(dev, mux->data.n_values, sizeof(*mux->data.values),
GFP_KERNEL);
if (!values)
return -ENOMEM;
for_each_child_of_node(np, child) {
of_property_read_u32(child, "reg", values + i);
device_for_each_child_node(dev, child) {
if (is_acpi_device_node(child)) {
ret = acpi_get_local_address(ACPI_HANDLE_FWNODE(child),
&values[i]);
if (ret) {
fwnode_handle_put(child);
return dev_err_probe(dev, ret,
"Cannot get address\n");
}
} else {
fwnode_property_read_u32(child, "reg", &values[i]);
}
i++;
}
mux->data.values = values;
if (!of_property_read_u32(np, "idle-state", &mux->data.idle))
if (!device_property_read_u32(dev, "idle-state", &mux->data.idle))
mux->data.idle_in_use = true;
/* map address from "reg" if exists */
if (of_address_to_resource(np, 0, &res) == 0) {
mux->data.reg_size = resource_size(&res);
mux->data.reg = devm_ioremap_resource(&pdev->dev, &res);
if (IS_ERR(mux->data.reg))
return PTR_ERR(mux->data.reg);
}
return 0;
}
#else
static int i2c_mux_reg_probe_dt(struct regmux *mux,
struct platform_device *pdev)
{
return 0;
}
#endif
static int i2c_mux_reg_probe(struct platform_device *pdev)
{
@@ -169,34 +160,29 @@ static int i2c_mux_reg_probe(struct platform_device *pdev)
memcpy(&mux->data, dev_get_platdata(&pdev->dev),
sizeof(mux->data));
} else {
ret = i2c_mux_reg_probe_dt(mux, pdev);
ret = i2c_mux_reg_probe_fw(mux, &pdev->dev);
if (ret < 0)
return dev_err_probe(&pdev->dev, ret,
"Error parsing device tree");
"Error parsing firmware description\n");
}
parent = i2c_get_adapter(mux->data.parent);
if (!parent)
return -EPROBE_DEFER;
if (!mux->data.reg) {
dev_info(&pdev->dev,
"Register not set, using platform resource\n");
mux->data.reg = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
if (IS_ERR(mux->data.reg)) {
ret = PTR_ERR(mux->data.reg);
goto err_put_parent;
}
if (IS_ERR(mux->data.reg))
return PTR_ERR(mux->data.reg);
mux->data.reg_size = resource_size(res);
}
if (mux->data.reg_size != 4 && mux->data.reg_size != 2 &&
mux->data.reg_size != 1) {
dev_err(&pdev->dev, "Invalid register size\n");
ret = -EINVAL;
goto err_put_parent;
return -EINVAL;
}
parent = i2c_get_adapter(mux->data.parent);
if (!parent)
return -EPROBE_DEFER;
muxc = i2c_mux_alloc(parent, &pdev->dev, mux->data.n_values, 0, 0,
i2c_mux_reg_select, NULL);
if (!muxc) {