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Message-ID: <20250217142758.540601-2-koichiro.den@canonical.com>
Date: Mon, 17 Feb 2025 23:27:56 +0900
From: Koichiro Den <koichiro.den@...onical.com>
To: linux-gpio@...r.kernel.org
Cc: brgl@...ev.pl,
geert+renesas@...der.be,
linus.walleij@...aro.org,
maciej.borzecki@...onical.com,
linux-kernel@...r.kernel.org
Subject: [PATCH 1/3] gpio: pseudo: common helper functions for pseudo gpio devices
Both gpio-sim and gpio-virtuser share a mechanism to instantiate a
platform device and wait synchronously for probe completion.
With gpio-aggregator adopting the same approach in a later commit for
its configfs interface, it's time to factor out the common code.
Add gpio-pseudo.[ch] to house helper functions used by all the pseudo
GPIO device implementations.
No functional change.
Signed-off-by: Koichiro Den <koichiro.den@...onical.com>
---
drivers/gpio/Kconfig | 4 ++
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio-pseudo.c | 86 ++++++++++++++++++++++++++++++++++++++
drivers/gpio/gpio-pseudo.h | 24 +++++++++++
4 files changed, 115 insertions(+)
create mode 100644 drivers/gpio/gpio-pseudo.c
create mode 100644 drivers/gpio/gpio-pseudo.h
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 56c1f30ac195..1e2c95e03a95 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -1863,6 +1863,10 @@ config GPIO_MPSSE
endmenu
+# This symbol is selected by some pseudo gpio device implementations
+config GPIO_PSEUDO
+ bool
+
menu "Virtual GPIO drivers"
config GPIO_AGGREGATOR
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index af3ba4d81b58..5eb54147a1ab 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -136,6 +136,7 @@ obj-$(CONFIG_GPIO_PISOSR) += gpio-pisosr.o
obj-$(CONFIG_GPIO_PL061) += gpio-pl061.o
obj-$(CONFIG_GPIO_PMIC_EIC_SPRD) += gpio-pmic-eic-sprd.o
obj-$(CONFIG_GPIO_POLARFIRE_SOC) += gpio-mpfs.o
+obj-$(CONFIG_GPIO_PSEUDO) += gpio-pseudo.o
obj-$(CONFIG_GPIO_PXA) += gpio-pxa.o
obj-$(CONFIG_GPIO_RASPBERRYPI_EXP) += gpio-raspberrypi-exp.o
obj-$(CONFIG_GPIO_RC5T583) += gpio-rc5t583.o
diff --git a/drivers/gpio/gpio-pseudo.c b/drivers/gpio/gpio-pseudo.c
new file mode 100644
index 000000000000..6e3da05440d8
--- /dev/null
+++ b/drivers/gpio/gpio-pseudo.c
@@ -0,0 +1,86 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Helper functions for Pseudo GPIOs
+ *
+ * Copyright 2025 Canonical Ltd.
+ */
+
+#include "gpio-pseudo.h"
+
+static int pseudo_gpio_notifier_call(struct notifier_block *nb,
+ unsigned long action,
+ void *data)
+{
+ struct pseudo_gpio_common *common;
+ struct device *dev = data;
+
+ common = container_of(nb, struct pseudo_gpio_common, bus_notifier);
+ if (!device_match_name(dev, common->name))
+ return NOTIFY_DONE;
+
+ switch (action) {
+ case BUS_NOTIFY_BOUND_DRIVER:
+ common->driver_bound = true;
+ break;
+ case BUS_NOTIFY_DRIVER_NOT_BOUND:
+ common->driver_bound = false;
+ break;
+ default:
+ return NOTIFY_DONE;
+ }
+
+ complete(&common->probe_completion);
+ return NOTIFY_OK;
+}
+
+void pseudo_gpio_init(struct pseudo_gpio_common *common)
+{
+ memset(common, 0, sizeof(*common));
+ init_completion(&common->probe_completion);
+ common->bus_notifier.notifier_call = pseudo_gpio_notifier_call;
+}
+EXPORT_SYMBOL_GPL(pseudo_gpio_init);
+
+int pseudo_gpio_register(struct pseudo_gpio_common *common,
+ struct platform_device_info *pdevinfo)
+{
+ struct platform_device *pdev;
+ char *name;
+
+ name = kasprintf(GFP_KERNEL, "%s.%u", pdevinfo->name, pdevinfo->id);
+ if (!name)
+ return -ENOMEM;
+
+ common->driver_bound = false;
+ common->name = name;
+ reinit_completion(&common->probe_completion);
+ bus_register_notifier(&platform_bus_type, &common->bus_notifier);
+
+ pdev = platform_device_register_full(pdevinfo);
+ if (IS_ERR(pdev)) {
+ bus_unregister_notifier(&platform_bus_type, &common->bus_notifier);
+ kfree(common->name);
+ return PTR_ERR(pdev);
+ }
+
+ wait_for_completion(&common->probe_completion);
+ bus_unregister_notifier(&platform_bus_type, &common->bus_notifier);
+
+ if (!common->driver_bound) {
+ platform_device_unregister(pdev);
+ kfree(common->name);
+ return -ENXIO;
+ }
+
+ common->pdev = pdev;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(pseudo_gpio_register);
+
+void pseudo_gpio_unregister(struct pseudo_gpio_common *common)
+{
+ platform_device_unregister(common->pdev);
+ kfree(common->name);
+ common->pdev = NULL;
+}
+EXPORT_SYMBOL_GPL(pseudo_gpio_unregister);
diff --git a/drivers/gpio/gpio-pseudo.h b/drivers/gpio/gpio-pseudo.h
new file mode 100644
index 000000000000..093112b6cce5
--- /dev/null
+++ b/drivers/gpio/gpio-pseudo.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef GPIO_PSEUDO_H
+#define GPIO_PSEUDO_H
+
+#include <linux/completion.h>
+#include <linux/platform_device.h>
+
+struct pseudo_gpio_common {
+ struct platform_device *pdev;
+ const char *name;
+
+ /* Synchronize with probe */
+ struct notifier_block bus_notifier;
+ struct completion probe_completion;
+ bool driver_bound;
+};
+
+void pseudo_gpio_init(struct pseudo_gpio_common *common);
+int pseudo_gpio_register(struct pseudo_gpio_common *common,
+ struct platform_device_info *pdevinfo);
+void pseudo_gpio_unregister(struct pseudo_gpio_common *common);
+
+#endif /* GPIO_PSEUDO_H */
--
2.45.2
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