Re: [PATCH v3 4/8] of: unittest: Test fw_devlink with GPIO nexus maps

[Saravana Kannan]

On Tue, Oct 20, 2026 at 6:00 AM Ernest Van Hoecke
<ernestvanhoecke@xxxxxxxxx> wrote:
>
> From: Ernest Van Hoecke <ernest.vanhoecke@xxxxxxxxxxx>
>
> Add OF unit tests that call the fw_devlink add_links operation for GPIOs
> routed through nexus maps. Verify that each mapped consumer has exactly
> one link to the final GPIO provider rather than to the nexus.
>
> Also cover direct references and all GPIO property spellings recognized
> by fw_devlink, including the deprecated singular and unprefixed forms.
>
> The gpio-map routes its entries to different providers so that selecting
> the wrong entry is caught as well.
>
> Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxxxxxxxx>
> Reviewed-by: Linus Walleij <linusw@xxxxxxxxxx>
> Signed-off-by: Ernest Van Hoecke <ernest.vanhoecke@xxxxxxxxxxx>
> ---
> v3: Route gpio-map entries to two providers, use a middle entry (Herve)
> v2: https://lore.kernel.org/r/20260910-fw-devlink-nexus-ready-v2-3-17ac82dbe226@xxxxxxxxxxx
> ---
>  drivers/of/unittest-data/tests-phandle.dtsi | 39 +++++++++++++++
>  drivers/of/unittest.c                       | 75 +++++++++++++++++++++++++++++
>  2 files changed, 114 insertions(+)
>
> diff --git a/drivers/of/unittest-data/tests-phandle.dtsi b/drivers/of/unittest-data/tests-phandle.dtsi
> index 554a996b2ef1..f5d7ee072c90 100644
> --- a/drivers/of/unittest-data/tests-phandle.dtsi
> +++ b/drivers/of/unittest-data/tests-phandle.dtsi
> @@ -79,6 +79,45 @@ consumer-b {
>                                 phandle-list-bad-args = <&provider2 1 0>,
>                                                         <&provider4 0>;
>                         };
> +
> +                       fw-devlink-tests {
> +                               gpio_provider_a: gpio-controller-a {
> +                                       #gpio-cells = <2>;
> +                               };
> +
> +                               gpio_provider_b: gpio-controller-b {
> +                                       #gpio-cells = <2>;
> +                               };
> +
> +                               fwdevlink_nexus: nexus {
> +                                       #gpio-cells = <2>;
> +                                       gpio-map = <1 0 &gpio_provider_a 3 0>,
> +                                                  <2 0 &gpio_provider_b 5 0>,
> +                                                  <3 0 &gpio_provider_a 7 0>;
> +                                       gpio-map-mask = <0xffffffff 0>;
> +                                       gpio-map-pass-thru = <0 0xffffffff>;
> +                               };
> +
> +                               gpio-compat-consumer {
> +                                       gpios = <&fwdevlink_nexus 2 1>;
> +                               };
> +
> +                               gpio-compat-singular-consumer {
> +                                       gpio = <&fwdevlink_nexus 2 1>;
> +                               };
> +
> +                               gpio-consumer {
> +                                       test-gpios = <&fwdevlink_nexus 2 1>;
> +                               };
> +
> +                               gpio-direct-consumer {
> +                                       test-gpios = <&gpio_provider_a 1 0>;
> +                               };
> +
> +                               gpio-singular-consumer {
> +                                       test-gpio = <&fwdevlink_nexus 2 1>;
> +                               };
> +                       };
>                 };
>         };
>  };
> diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c
> index e255f54f4d76..f15c110dbf4d 100644
> --- a/drivers/of/unittest.c
> +++ b/drivers/of/unittest.c
> @@ -10,6 +10,7 @@
>  #include <linux/dma-direct.h> /* to test phys_to_dma/dma_to_phys */
>  #include <linux/err.h>
>  #include <linux/errno.h>
> +#include <linux/fwnode.h>
>  #include <linux/hashtable.h>
>  #include <linux/libfdt.h>
>  #include <linux/of.h>
> @@ -710,6 +711,79 @@ static void __init of_unittest_parse_phandle_with_args_map(void)
>         }
>  }
>
> +static void __init of_unittest_fw_devlink_supplier(struct device_node *tests,
> +                                                  const char *consumer_name,
> +                                                  const char *supplier_name)
> +{
> +       struct device_node *consumer, *supplier;
> +       struct fwnode_handle *consumer_fwnode;
> +       struct fwnode_link *link;
> +       unsigned int link_count = 0;
> +       bool found = false;
> +       int rc;
> +
> +       consumer = of_get_child_by_name(tests, consumer_name);
> +       supplier = of_get_child_by_name(tests, supplier_name);
> +       if (unittest(consumer && supplier, "missing consumer %s or supplier %s\n",
> +                    consumer_name, supplier_name))
> +               goto put_nodes;
> +
> +       consumer_fwnode = of_fwnode_handle(consumer);
> +       fwnode_links_purge(consumer_fwnode);

Why this line? Aren't you controlling the exact set of properties in
the test nodes?

-Saravana

> +       rc = fwnode_call_int_op(consumer_fwnode, add_links);
> +       if (rc == -EOPNOTSUPP) {
> +               pr_info_once("fw_devlink tests skipped: OF supplier links are not supported\n");
> +               goto purge_links;
> +       }
> +       if (unittest(!rc, "failed to add links for %pOF: %d\n", consumer, rc))
> +               goto purge_links;
> +
> +       /*
> +        * The suppliers list should normally be accessed with fwnode_link_lock
> +        * held, but that lock is private to the driver core. These test nodes
> +        * are isolated and have no concurrent link updates.
> +        */
> +       list_for_each_entry(link, &consumer_fwnode->suppliers, c_hook) {
> +               link_count++;
> +               if (link->supplier == of_fwnode_handle(supplier))
> +                       found = true;
> +       }
> +
> +       unittest(link_count == 1, "%pOF has %u suppliers, expected 1\n", consumer, link_count);
> +       unittest(found, "%pOF is not linked to supplier %pOF\n", consumer, supplier);
> +
> +purge_links:
> +       fwnode_links_purge(consumer_fwnode);
> +put_nodes:
> +       of_node_put(consumer);
> +       of_node_put(supplier);
> +}
> +
> +static void __init of_unittest_fw_devlink(void)
> +{
> +       static const struct {
> +               const char *consumer;
> +               const char *supplier;
> +       } cases[] = {
> +               { "gpio-compat-consumer", "gpio-controller-b" },
> +               { "gpio-compat-singular-consumer", "gpio-controller-b" },
> +               { "gpio-consumer", "gpio-controller-b" },
> +               { "gpio-direct-consumer", "gpio-controller-a" },
> +               { "gpio-singular-consumer", "gpio-controller-b" },
> +       };
> +       struct device_node *tests;
> +       int i;
> +
> +       tests = of_find_node_by_path("/testcase-data/phandle-tests/fw-devlink-tests");
> +       if (unittest(tests, "missing fw_devlink test data\n"))
> +               return;
> +
> +       for (i = 0; i < ARRAY_SIZE(cases); i++)
> +               of_unittest_fw_devlink_supplier(tests, cases[i].consumer, cases[i].supplier);
> +
> +       of_node_put(tests);
> +}
> +
>  static void __init of_unittest_property_string(void)
>  {
>         const char *strings[4];
> @@ -4533,6 +4607,7 @@ static int __init of_unittest(void)
>         of_unittest_dynamic();
>         of_unittest_parse_phandle_with_args();
>         of_unittest_parse_phandle_with_args_map();
> +       of_unittest_fw_devlink();
>         of_unittest_printf();
>         of_unittest_property_string();
>         of_unittest_property_copy();
>
> --
> 2.43.0
>