[{"id":3673493,"web_url":"http://patchwork.ozlabs.org/comment/3673493/","msgid":"","list_archive_url":null,"date":"2026-04-04T18:25:43","subject":"Re: [PATCH v2 4/4] platform/x86: x86-android-tablets: enable fwnode\n matching of GPIO chips","submitter":{"id":64267,"url":"http://patchwork.ozlabs.org/api/people/64267/","name":"Rafael J. Wysocki","email":"rafael@kernel.org"},"content":"On Thu, Apr 2, 2026 at 2:54 PM Bartosz Golaszewski\n wrote:\n>\n> In order to allow GPIOLIB to match cherryview and baytrail GPIO\n> controllers by their firmware nodes instead of their names, we need to\n> attach the - currently \"dangling\" - existing software nodes to their\n> target devices dynamically.\n>\n> We deal with devices described in ACPI so set up a bus notifier waiting\n> for the ADD events. We know the name of the device we're waiting for so\n> match against it and - on match - assign the appropriate software node\n> as the secondary firmware node of the underlying ACPI node. In case the\n> event was emitted earlier than this driver's probe: also make sure the\n> device was not added before.\n>\n> Scheduling fine-grained devres actions allows for proper teardown and\n> unsetting of the secondary firmware nodes.\n>\n> Signed-off-by: Bartosz Golaszewski \n> ---\n> drivers/platform/x86/x86-android-tablets/core.c | 127 +++++++++++++++++++++++-\n> 1 file changed, 124 insertions(+), 3 deletions(-)\n>\n> diff --git a/drivers/platform/x86/x86-android-tablets/core.c b/drivers/platform/x86/x86-android-tablets/core.c\n> index 021009e9085bec3db9c4daa1f6235600210a6099..9e6e8f272dfe16cda421b569802045c3d94fc0ab 100644\n> --- a/drivers/platform/x86/x86-android-tablets/core.c\n> +++ b/drivers/platform/x86/x86-android-tablets/core.c\n> @@ -13,10 +13,12 @@\n> #include \n> #include \n> #include \n> +#include \n> #include \n> #include \n> #include \n> #include \n> +#include \n> #include \n> #include \n> #include \n> @@ -360,6 +362,124 @@ static const struct software_node *cherryview_gpiochip_node_group[] = {\n> NULL\n> };\n>\n> +struct auto_secondary_data {\n> + struct notifier_block nb;\n> + struct device *parent;\n> +};\n> +\n> +static void auto_secondary_unset(void *data)\n> +{\n> + struct fwnode_handle *fwnode = data;\n> +\n> + fwnode->secondary = NULL;\n> +}\n> +\n> +static int acpi_set_secondary_fwnode(struct device *parent, struct device *dev,\n> + const struct software_node *const swnode)\n> +{\n> + struct acpi_device *device = to_acpi_device(dev);\n> + struct fwnode_handle *fwnode;\n> + int ret;\n> +\n> + fwnode = software_node_fwnode(swnode);\n> + if (WARN_ON(!fwnode))\n> + return -ENOENT;\n> +\n> + fwnode->secondary = ERR_PTR(-ENODEV);\n> + device->fwnode.secondary = fwnode;\n> +\n> + ret = devm_add_action_or_reset(parent, auto_secondary_unset, &device->fwnode);\n> + if (ret)\n> + dev_err(parent, \"Failed to schedule the unset action for secondary fwnode\\n\");\n> +\n> + return ret;\n> +}\n> +\n> +static int acpi_auto_secondary_notifier(struct notifier_block *nb,\n> + unsigned long action, void *data)\n> +{\n> + struct auto_secondary_data *auto_sec = container_of(nb, struct auto_secondary_data, nb);\n> + const struct software_node *const *swnode;\n> + struct device *dev = data;\n> + int ret;\n> +\n> + switch (action) {\n> + case BUS_NOTIFY_ADD_DEVICE:\n> + for (swnode = gpiochip_node_group; *swnode; swnode++) {\n> + if (strcmp((*swnode)->name, dev_name(dev)) == 0) {\n> + ret = acpi_set_secondary_fwnode(auto_sec->parent, dev, *swnode);\n> + return ret ? NOTIFY_BAD : NOTIFY_OK;\n> + }\n> + }\n> + break;\n> + default:\n> + break;\n> + }\n> +\n> + return NOTIFY_DONE;\n> +}\n> +\n> +static void auto_secondary_unregister_node_group(void *data)\n> +{\n> + const struct software_node **nodes = data;\n> +\n> + software_node_unregister_node_group(nodes);\n> +}\n> +\n> +static void auto_secondary_unregister_notifier(void *data)\n> +{\n> + struct notifier_block *nb = data;\n> +\n> + bus_unregister_notifier(&acpi_bus_type, nb);\n> +}\n\nInstead of exporting acpi_bus_type in the previous patch and defining\nthis function here, can you define\n\nvoid acpi_bus_unregister_notifier(void *data)\n{\n struct notifier_block *nb = data;\n\n bus_unregister_notifier(&acpi_bus_type, nb);\n}\n\nin the previous patch and use it here?\n\n> +\n> +static int auto_secondary_fwnode_init(struct device *parent)\n> +{\n> + const struct software_node *const *swnode;\n> + struct auto_secondary_data *data;\n> + int ret;\n> +\n> + ret = software_node_register_node_group(gpiochip_node_group);\n> + if (ret)\n> + return ret;\n> +\n> + ret = devm_add_action_or_reset(parent,\n> + auto_secondary_unregister_node_group,\n> + gpiochip_node_group);\n> + if (ret)\n> + return ret;\n> +\n> + data = devm_kzalloc(parent, sizeof(*data), GFP_KERNEL);\n> + if (!data)\n> + return -ENOMEM;\n> +\n> + data->nb.notifier_call = acpi_auto_secondary_notifier;\n> + data->parent = parent;\n> +\n> + ret = bus_register_notifier(&acpi_bus_type, &data->nb);\n> + if (ret)\n> + return ret;\n> +\n> + ret = devm_add_action_or_reset(parent,\n> + auto_secondary_unregister_notifier,\n> + &data->nb);\n> + if (ret)\n> + return ret;\n> +\n> + /* Device may have been already added. */\n> + for (swnode = gpiochip_node_group; *swnode; swnode++) {\n> + struct device *dev __free(put_device) =\n> + bus_find_device_by_name(&acpi_bus_type, NULL, (*swnode)->name);\n> + if (dev) {\n> + ret = acpi_set_secondary_fwnode(parent, dev, *swnode);\n> + if (ret)\n> + return ret;\n> + }\n> + }\n> +\n> + return 0;\n> +}\n> +\n> static void x86_android_tablet_remove(struct platform_device *pdev)\n> {\n> int i;\n> @@ -391,7 +511,6 @@ static void x86_android_tablet_remove(struct platform_device *pdev)\n>\n> software_node_unregister_node_group(gpio_button_swnodes);\n> software_node_unregister_node_group(swnode_group);\n> - software_node_unregister_node_group(gpiochip_node_group);\n> }\n>\n> static __init int x86_android_tablet_probe(struct platform_device *pdev)\n> @@ -427,9 +546,11 @@ static __init int x86_android_tablet_probe(struct platform_device *pdev)\n> break;\n> }\n>\n> - ret = software_node_register_node_group(gpiochip_node_group);\n> - if (ret)\n> + ret = auto_secondary_fwnode_init(&pdev->dev);\n> + if (ret) {\n> + x86_android_tablet_remove(pdev);\n> return ret;\n> + }\n>\n> ret = software_node_register_node_group(dev_info->swnode_group);\n> if (ret) {\n>\n> --\n> 2.47.3\n>","headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linux-gpio@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256\n header.s=k20201202 header.b=dasMaZUC;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c0a:e001:db::12fc:5321; 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Wysocki\" ","Date":"Sat, 4 Apr 2026 20:25:43 +0200","X-Gmail-Original-Message-ID":"\n ","X-Gm-Features":"AQROBzD6YmXrnAzgz9aL6fqWq1iOyolotQRnTtrF6brMuNKBBNGJLMNRaP4UCiA","Message-ID":"\n ","Subject":"Re: [PATCH v2 4/4] platform/x86: x86-android-tablets: enable fwnode\n matching of GPIO chips","To":"Bartosz Golaszewski ","Cc":"Andy Shevchenko ,\n Daniel Scally ,\n Heikki Krogerus ,\n Sakari Ailus ,\n Greg Kroah-Hartman ,\n \"Rafael J. Wysocki\" , Danilo Krummrich ,\n Mika Westerberg ,\n Andy Shevchenko , Linus Walleij ,\n Hans de Goede ,\n =?utf-8?q?Ilpo_J=C3=A4rvinen?= ,\n Dmitry Torokhov , Len Brown ,\n linux-acpi@vger.kernel.org, driver-core@lists.linux.dev,\n linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org,\n platform-driver-x86@vger.kernel.org, brgl@kernel.org","Content-Type":"text/plain; charset=\"UTF-8\"","Content-Transfer-Encoding":"quoted-printable"}}]