From eb6a745a18e420b826994847302f942a544a8b65 Mon Sep 17 00:00:00 2001
From: Norman Feske <norman.feske@genode-labs.com>
Date: Thu, 6 Oct 2022 18:31:34 +0200
Subject: [PATCH] platform: add Guard utils for Clock/Reset/Power

These utilities simplify the control of clocks, resets, and power
domains from within the platform driver.

This is needed when driving a low-level device directly from the
platform driver, for example for driving the mbox mechanism to access
the system-control processor of the PinePhone.
---
 repos/os/src/drivers/platform/clock.h | 7 +++++++
 repos/os/src/drivers/platform/power.h | 7 +++++++
 repos/os/src/drivers/platform/reset.h | 7 +++++++
 3 files changed, 21 insertions(+)

diff --git a/repos/os/src/drivers/platform/clock.h b/repos/os/src/drivers/platform/clock.h
index 170d99fbfb..ed9296532c 100644
--- a/repos/os/src/drivers/platform/clock.h
+++ b/repos/os/src/drivers/platform/clock.h
@@ -60,6 +60,13 @@ class Driver::Clock : Clocks::Element, Interface
 
 		void enable()  { _switch.use();   }
 		void disable() { _switch.unuse(); }
+
+		struct Guard : Genode::Noncopyable
+		{
+			Clock &_clock;
+			Guard(Clock &clock) : _clock(clock) { _clock.enable(); }
+			~Guard() { _clock.disable(); }
+		};
 };
 
 
diff --git a/repos/os/src/drivers/platform/power.h b/repos/os/src/drivers/platform/power.h
index 676dbd90a7..71039fd56f 100644
--- a/repos/os/src/drivers/platform/power.h
+++ b/repos/os/src/drivers/platform/power.h
@@ -51,6 +51,13 @@ class Driver::Power : Powers::Element, Interface
 
 		void on()  { _switch.use();   }
 		void off() { _switch.unuse(); }
+
+		struct Guard : Genode::Noncopyable
+		{
+			Power &_power;
+			Guard(Power &power) : _power(power) { _power.on(); }
+			~Guard() { _power.off(); }
+		};
 };
 
 #endif /* _POWER_H_ */
diff --git a/repos/os/src/drivers/platform/reset.h b/repos/os/src/drivers/platform/reset.h
index e89b6f99d6..f2b61fc389 100644
--- a/repos/os/src/drivers/platform/reset.h
+++ b/repos/os/src/drivers/platform/reset.h
@@ -51,6 +51,13 @@ class Driver::Reset : Resets::Element, Interface
 
 		void deassert() { _switch.use();   }
 		void assert()   { _switch.unuse(); }
+
+		struct Guard : Genode::Noncopyable
+		{
+			Reset &_reset;
+			Guard(Reset &reset) : _reset(reset) { _reset.deassert(); }
+			~Guard() { _reset.assert(); }
+		};
 };
 
 #endif /* _RESET_H_ */