dm: button: add an uclass for button

Add a new uclass for button that implements two functions:
- button_get_by_label
- button_get_status

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Philippe Reynes <philippe.reynes@softathome.com>

3 files changed, 60 insertions, 0 deletions

diff --git a/drivers/button/Kconfig b/drivers/button/Kconfig
new file mode 100644
index 0000000000..83018589e5
--- /dev/null
+++ b/drivers/button/Kconfig
@@ -0,0 +1,12 @@
+menu "Button Support"
+
+config BUTTON
+	bool "Enable button support"
+	depends on DM
+	help
+	  Many boards have buttons which can be used to change behaviour (reset, ...).
+	  U-Boot provides a uclass API to implement this feature. Button drivers
+	  can provide access to board-specific buttons. Use of the device tree
+	  for configuration is encouraged.
+
+endmenu
diff --git a/drivers/button/Makefile b/drivers/button/Makefile
new file mode 100644
index 0000000000..0b4c128cff
--- /dev/null
+++ b/drivers/button/Makefile
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Copyright (C) 2020 Philippe Reynes <philippe.reynes@softathome.com>
+
+obj-$(CONFIG_BUTTON) += button-uclass.o
diff --git a/drivers/button/button-uclass.c b/drivers/button/button-uclass.c
new file mode 100644
index 0000000000..1c742c265c
--- /dev/null
+++ b/drivers/button/button-uclass.c
@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2020 Philippe Reynes <philippe.reynes@softathome.com>
+ *
+ * Based on led-uclass.c
+ */
+
+#include <common.h>
+#include <button.h>
+#include <dm.h>
+#include <dm/uclass-internal.h>
+
+int button_get_by_label(const char *label, struct udevice **devp)
+{
+	struct udevice *dev;
+	struct uclass *uc;
+
+	uclass_id_foreach_dev(UCLASS_BUTTON, dev, uc) {
+		struct button_uc_plat *uc_plat = dev_get_uclass_platdata(dev);
+
+		/* Ignore the top-level button node */
+		if (uc_plat->label && !strcmp(label, uc_plat->label))
+			return uclass_get_device_tail(dev, 0, devp);
+	}
+
+	return -ENODEV;
+}
+
+enum button_state_t button_get_state(struct udevice *dev)
+{
+	struct button_ops *ops = button_get_ops(dev);
+
+	if (!ops->get_state)
+		return -ENOSYS;
+
+	return ops->get_state(dev);
+}
+
+UCLASS_DRIVER(button) = {
+	.id		= UCLASS_BUTTON,
+	.name		= "button",
+	.per_device_platdata_auto_alloc_size = sizeof(struct button_uc_plat),
+};