rust: clk: Add helpers for Rust code

Non-trivial C macros and inlined C functions cannot be used directly
in the Rust code and are used via functions ("helpers") that wrap
those so that they can be called from Rust.

In order to prepare for adding Rust abstractions for the clock APIs,
add clock helpers required by the Rust implementation.

Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

Author: vireshk

MAINTAINERS

@@ -5883,6 +5883,7 @@ F:	include/dt-bindings/clock/
 F:	include/linux/clk-pr*
 F:	include/linux/clk/
 F:	include/linux/of_clk.h
+F:	rust/helpers/clk.c
 X:	drivers/clk/clkdev.c
 
 COMMON INTERNET FILE SYSTEM CLIENT (CIFS and SMB3)

rust/bindings/bindings_helper.h

@@ -10,6 +10,7 @@
 #include <linux/blk-mq.h>
 #include <linux/blk_types.h>
 #include <linux/blkdev.h>
+#include <linux/clk.h>
 #include <linux/cpumask.h>
 #include <linux/cred.h>
 #include <linux/device/faux.h>

rust/helpers/clk.c

@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/clk.h>
+
+/*
+ * The "inline" implementation of below helpers are only available when
+ * CONFIG_HAVE_CLK or CONFIG_HAVE_CLK_PREPARE aren't set.
+ */
+#ifndef CONFIG_HAVE_CLK
+struct clk *rust_helper_clk_get(struct device *dev, const char *id)
+{
+	return clk_get(dev, id);
+}
+
+void rust_helper_clk_put(struct clk *clk)
+{
+	clk_put(clk);
+}
+
+int rust_helper_clk_enable(struct clk *clk)
+{
+	return clk_enable(clk);
+}
+
+void rust_helper_clk_disable(struct clk *clk)
+{
+	clk_disable(clk);
+}
+
+unsigned long rust_helper_clk_get_rate(struct clk *clk)
+{
+	return clk_get_rate(clk);
+}
+
+int rust_helper_clk_set_rate(struct clk *clk, unsigned long rate)
+{
+	return clk_set_rate(clk, rate);
+}
+#endif
+
+#ifndef CONFIG_HAVE_CLK_PREPARE
+int rust_helper_clk_prepare(struct clk *clk)
+{
+	return clk_prepare(clk);
+}
+
+void rust_helper_clk_unprepare(struct clk *clk)
+{
+	clk_unprepare(clk);
+}
+#endif
+
+struct clk *rust_helper_clk_get_optional(struct device *dev, const char *id)
+{
+	return clk_get_optional(dev, id);
+}
+
+int rust_helper_clk_prepare_enable(struct clk *clk)
+{
+	return clk_prepare_enable(clk);
+}
+
+void rust_helper_clk_disable_unprepare(struct clk *clk)
+{
+	clk_disable_unprepare(clk);
+}

rust/helpers/helpers.c

@@ -11,6 +11,7 @@
 #include "bug.c"
 #include "build_assert.c"
 #include "build_bug.c"
+#include "clk.c"
 #include "cpumask.c"
 #include "cred.c"
 #include "device.c"