Re: [PATCH RFC 02/11] ACPI: Introduce irq_get() for static fwnodes

[Ashok Raj]

On Fri, Sep 25, 2026 at 09:48:01AM +0200, Lorenzo Pieralisi wrote:
> To describe and map GSIs for firmware nodes created out of ACPI static
> table entries in a uniform way it is required to define some standard
> properties and attach them to ACPI static fwnode as secondary nodes.
> 
> Define properties names to describe GSIs and their trigger-mode/polarity,
> and implement an irq_get() callback for static fwnodes so that core code
> can retrieve and map IRQs for ACPI static fwnodes in standard manner.
> 
> An empty stub for property_read_string_array() is also added, so that
> the fwnode_irq_get_byname() interface falls back (through
> fwnode_property_read_string_array()) to the secondary
> fwnode to grab the "interrupt-names" property.
> 
> Signed-off-by: Lorenzo Pieralisi <lpieralisi@xxxxxxxxxx>
> Cc: Bartosz Golaszewski <brgl@xxxxxxxxxx>
> Cc: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx>
> ---
>  drivers/acpi/property.c | 69 ++++++++++++++++++++++++++++++++++++++++++++++++-
>  include/linux/acpi.h    |  4 +++
>  2 files changed, 72 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c
> index 8ee5a1f0eb48..c609100c08db 100644
> --- a/drivers/acpi/property.c
> +++ b/drivers/acpi/property.c
> @@ -1766,7 +1766,74 @@ static int acpi_fwnode_irq_get(const struct fwnode_handle *fwnode,
>  
>  DECLARE_ACPI_FWNODE_OPS(acpi_device_fwnode_ops);
>  DECLARE_ACPI_FWNODE_OPS(acpi_data_fwnode_ops);
> -const struct fwnode_operations acpi_static_fwnode_ops;
> +
> +static int acpi_static_fwnode_read_u32_prop_index(const struct fwnode_handle *fwnode,
> +						  const char *propname,
> +						  unsigned int index, u32 *value)
> +{
> +	u32 *values;
> +	int ret, count;
> +
> +	count = fwnode_property_count_u32(fwnode, propname);
> +	if (count < 0)
> +		return count;
> +
> +	if (index >= count)
> +		return -ENOENT;
> +
> +	values = kcalloc(count, sizeof(*values), GFP_KERNEL);
> +	if (!values)
> +		return -ENOMEM;
> +
> +	ret = fwnode_property_read_u32_array(fwnode, propname, values, count);
> +	if (!ret)
> +		*value = values[index];
> +

You lookup with a propname, and then qualify with and index? is it
possible to have the different index but same propname? 

Alternately you can send the list to caller and they can use the ones
they need?


> +	kfree(values);
> +	return ret;
> +}
> +
> +static int acpi_static_fwnode_read_string_array(const struct fwnode_handle *fwnode,
> +						const char *propname,
> +						const char **val, size_t nval)
> +{
> +	/* Route string handling to secondary software nodes */
> +	return -EINVAL;
> +}
> +
> +static int acpi_static_fwnode_irq_get(const struct fwnode_handle *fwnode,
> +				      unsigned int index)
> +{
> +	u32 gsi, trigger, polarity;
> +	int ret;
> +
> +	if (!fwnode->secondary)
> +		return -ENODEV;
> +
> +	fwnode = fwnode->secondary;
> +
> +	ret = acpi_static_fwnode_read_u32_prop_index(fwnode, ACPI_IRQ_PROP_GSI,
> +						index, &gsi);
> +	if (ret)
> +		return ret == -ENOENT ? -ENXIO : ret;
> +
> +	ret = acpi_static_fwnode_read_u32_prop_index(fwnode, ACPI_IRQ_PROP_GSI_TRIGGER,
> +						index, &trigger);
> +	if (ret)
> +		return ret == -ENOENT ? -ENXIO : ret;
> +
> +	ret = acpi_static_fwnode_read_u32_prop_index(fwnode, ACPI_IRQ_PROP_GSI_POLARITY,
> +						index, &polarity);
> +	if (ret)
> +		return ret == -ENOENT ? -ENXIO : ret;

Consolidate return to one place? 


-- 
/ashok.raj
ashok.raj@xxxxxxxxxxxxxxxx
Qualcomm Inc