linux-kernel - [PATCH v2] clk: Mark a fwnode as initialized when using CLK_OF

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Date:   Wed,  1 Mar 2023 17:46:38 -0800
From:   Saravana Kannan <saravanak@...gle.com>
To:     Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Saravana Kannan <saravanak@...gle.com>
Cc:     Linus Walleij <linus.walleij@...aro.org>, kernel-team@...roid.com,
        linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2] clk: Mark a fwnode as initialized when using
 CLK_OF_DECLARE() macro

We already mark fwnodes as initialized when they are registered as clock
providers. We do this so that fw_devlink can tell when a clock driver
doesn't use the driver core framework to probe/initialize its device.
This ensures fw_devlink doesn't block the consumers of such a clock
provider indefinitely.

However, some users of CLK_OF_DECLARE() macros don't use the same node
that matches the macro as the node for the clock provider, but they
initialize the entire node. To cover these cases, also mark the nodes
that match the macros as initialized when the init callback function is
called.

An example of this is "stericsson,u8500-clks" that's handled using
CLK_OF_DECLARE() and looks something like this:

clocks {
	compatible = "stericsson,u8500-clks";

	prcmu_clk: prcmu-clock {
		#clock-cells = <1>;
	};

	prcc_pclk: prcc-periph-clock {
		#clock-cells = <2>;
	};

	prcc_kclk: prcc-kernel-clock {
		#clock-cells = <2>;
	};

	prcc_reset: prcc-reset-controller {
		#reset-cells = <2>;
	};
	...
	...
};

This patch makes sure that "clocks" is marked as initialized so that
fw_devlink knows that all nodes under it have been initialized.

If the driver creates struct devices for some of the subnodes,
fw_devlink is smart enough to know to wait for those devices to probe.
So, no special handling is required for those cases.

Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Reported-by: Linus Walleij <linus.walleij@...aro.org>
Link: https://lore.kernel.org/lkml/CACRpkdamxDX6EBVjKX5=D3rkHp17f5pwGdBVhzFU90-0MHY6dQ@mail.gmail.com/
Fixes: 4a032827daa8 ("of: property: Simplify of_link_to_phandle()")
Signed-off-by: Saravana Kannan <saravanak@...gle.com>
---
 include/linux/clk-provider.h | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 842e72a5348f..c9f5276006a0 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -1363,7 +1363,13 @@ struct clk_hw_onecell_data {
 	struct clk_hw *hws[];
 };

-#define CLK_OF_DECLARE(name, compat, fn) OF_DECLARE_1(clk, name, compat, fn)
+#define CLK_OF_DECLARE(name, compat, fn) \
+	static void __init name##_of_clk_init_declare(struct device_node *np) \
+	{								\
+		fn(np);							\
+		fwnode_dev_initialized(of_fwnode_handle(np), true);	\
+	}								\
+	OF_DECLARE_1(clk, name, compat, name##_of_clk_init_declare)

 /*
  * Use this macro when you have a driver that requires two initialization
-- 
2.39.2.722.g9855ee24e9-goog