[PATCH v8 14/24] ACPI: property: Refactor acpi_fwnode_get_reference_args() to support nargs_prop
Rafael J. Wysocki
rafael at kernel.org
Mon Jul 7 09:48:09 PDT 2025
On Fri, Jul 4, 2025 at 9:07 AM Anup Patel <apatel at ventanamicro.com> wrote:
>
> From: Sunil V L <sunilvl at ventanamicro.com>
>
> Currently, acpi_fwnode_get_reference_args() delegates to the internal
> function __acpi_node_get_property_reference() to retrieve property
> references. However, this function does not handle the nargs_prop (cells
> property) parameter, and instead expects the number of arguments (nargs)
> to be known or hardcoded.
>
> As a result, when fwnode_property_get_reference_args() is used with a
> valid nargs_prop, the ACPI backend ignores it, whereas the Device Tree
> (DT) backend uses the #*-cells property from the reference node to
> determine the number of arguments dynamically.
>
> To support the nargs_prop in ACPI, refactor the code as follows:
>
> - Move the implementation from __acpi_node_get_property_reference()
> into acpi_fwnode_get_reference_args().
>
> - Update __acpi_node_get_property_reference() to call the (now updated)
> acpi_fwnode_get_reference_args() passing NULL as nargs_prop to keep
> the behavior of __acpi_node_get_property_reference() intact.
>
> Suggested-by: Andy Shevchenko <andriy.shevchenko at linux.intel.com>
> Signed-off-by: Sunil V L <sunilvl at ventanamicro.com>
> Signed-off-by: Anup Patel <apatel at ventanamicro.com>
LGTM now, so
Acked-by: Rafael J. Wysocki <rafael.j.wysocki at intel.com>
> ---
> drivers/acpi/property.c | 101 ++++++++++++++++++++--------------------
> 1 file changed, 50 insertions(+), 51 deletions(-)
>
> diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c
> index 436019d96027..d4863746fb11 100644
> --- a/drivers/acpi/property.c
> +++ b/drivers/acpi/property.c
> @@ -882,45 +882,10 @@ static struct fwnode_handle *acpi_parse_string_ref(const struct fwnode_handle *f
> return &dn->fwnode;
> }
>
> -/**
> - * __acpi_node_get_property_reference - returns handle to the referenced object
> - * @fwnode: Firmware node to get the property from
> - * @propname: Name of the property
> - * @index: Index of the reference to return
> - * @num_args: Maximum number of arguments after each reference
> - * @args: Location to store the returned reference with optional arguments
> - * (may be NULL)
> - *
> - * Find property with @name, verifify that it is a package containing at least
> - * one object reference and if so, store the ACPI device object pointer to the
> - * target object in @args->adev. If the reference includes arguments, store
> - * them in the @args->args[] array.
> - *
> - * If there's more than one reference in the property value package, @index is
> - * used to select the one to return.
> - *
> - * It is possible to leave holes in the property value set like in the
> - * example below:
> - *
> - * Package () {
> - * "cs-gpios",
> - * Package () {
> - * ^GPIO, 19, 0, 0,
> - * ^GPIO, 20, 0, 0,
> - * 0,
> - * ^GPIO, 21, 0, 0,
> - * }
> - * }
> - *
> - * Calling this function with index %2 or index %3 return %-ENOENT. If the
> - * property does not contain any more values %-ENOENT is returned. The NULL
> - * entry must be single integer and preferably contain value %0.
> - *
> - * Return: %0 on success, negative error code on failure.
> - */
> -int __acpi_node_get_property_reference(const struct fwnode_handle *fwnode,
> - const char *propname, size_t index, size_t num_args,
> - struct fwnode_reference_args *args)
> +static int acpi_fwnode_get_reference_args(const struct fwnode_handle *fwnode,
> + const char *propname, const char *nargs_prop,
> + unsigned int args_count, unsigned int index,
> + struct fwnode_reference_args *args)
> {
> const union acpi_object *element, *end;
> const union acpi_object *obj;
> @@ -999,7 +964,7 @@ int __acpi_node_get_property_reference(const struct fwnode_handle *fwnode,
>
> ret = acpi_get_ref_args(idx == index ? args : NULL,
> acpi_fwnode_handle(device),
> - &element, end, num_args);
> + &element, end, args_count);
> if (ret < 0)
> return ret;
>
> @@ -1017,7 +982,7 @@ int __acpi_node_get_property_reference(const struct fwnode_handle *fwnode,
>
> ret = acpi_get_ref_args(idx == index ? args : NULL,
> ref_fwnode, &element, end,
> - num_args);
> + args_count);
> if (ret < 0)
> return ret;
>
> @@ -1039,6 +1004,50 @@ int __acpi_node_get_property_reference(const struct fwnode_handle *fwnode,
>
> return -ENOENT;
> }
> +
> +/**
> + * __acpi_node_get_property_reference - returns handle to the referenced object
> + * @fwnode: Firmware node to get the property from
> + * @propname: Name of the property
> + * @index: Index of the reference to return
> + * @num_args: Maximum number of arguments after each reference
> + * @args: Location to store the returned reference with optional arguments
> + * (may be NULL)
> + *
> + * Find property with @name, verifify that it is a package containing at least
> + * one object reference and if so, store the ACPI device object pointer to the
> + * target object in @args->adev. If the reference includes arguments, store
> + * them in the @args->args[] array.
> + *
> + * If there's more than one reference in the property value package, @index is
> + * used to select the one to return.
> + *
> + * It is possible to leave holes in the property value set like in the
> + * example below:
> + *
> + * Package () {
> + * "cs-gpios",
> + * Package () {
> + * ^GPIO, 19, 0, 0,
> + * ^GPIO, 20, 0, 0,
> + * 0,
> + * ^GPIO, 21, 0, 0,
> + * }
> + * }
> + *
> + * Calling this function with index %2 or index %3 return %-ENOENT. If the
> + * property does not contain any more values %-ENOENT is returned. The NULL
> + * entry must be single integer and preferably contain value %0.
> + *
> + * Return: %0 on success, negative error code on failure.
> + */
> +int __acpi_node_get_property_reference(const struct fwnode_handle *fwnode,
> + const char *propname, size_t index,
> + size_t num_args,
> + struct fwnode_reference_args *args)
> +{
> + return acpi_fwnode_get_reference_args(fwnode, propname, NULL, index, num_args, args);
> +}
> EXPORT_SYMBOL_GPL(__acpi_node_get_property_reference);
>
> static int acpi_data_prop_read_single(const struct acpi_device_data *data,
> @@ -1558,16 +1567,6 @@ acpi_fwnode_property_read_string_array(const struct fwnode_handle *fwnode,
> val, nval);
> }
>
> -static int
> -acpi_fwnode_get_reference_args(const struct fwnode_handle *fwnode,
> - const char *prop, const char *nargs_prop,
> - unsigned int args_count, unsigned int index,
> - struct fwnode_reference_args *args)
> -{
> - return __acpi_node_get_property_reference(fwnode, prop, index,
> - args_count, args);
> -}
> -
> static const char *acpi_fwnode_get_name(const struct fwnode_handle *fwnode)
> {
> const struct acpi_device *adev;
> --
> 2.43.0
>
More information about the linux-riscv
mailing list