linux-kernel - [PATCH 03/13] clk: implement clk_hw_set

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Message-Id: <20230918-imx8mp-dtsi-v1-3-1d008b3237c0@skidata.com>
Date:   Mon, 18 Sep 2023 00:39:59 +0200
From:   Benjamin Bara <bbara93@...il.com>
To:     Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        Fabio Estevam <festevam@...il.com>,
        NXP Linux Team <linux-imx@....com>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Russell King <linux@...linux.org.uk>,
        Abel Vesa <abelvesa@...nel.org>, Peng Fan <peng.fan@....com>
Cc:     Frank Oltmanns <frank@...manns.dev>,
        Maxime Ripard <mripard@...nel.org>, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-clk@...r.kernel.org,
        Benjamin Bara <benjamin.bara@...data.com>
Subject: [PATCH 03/13] clk: implement clk_hw_set_rate()

From: Benjamin Bara <benjamin.bara@...data.com>

This function can be used to set the rate of a clock hardware from a
driver, e.g. to adapt the rate to a clock change coming from the parent.

Signed-off-by: Benjamin Bara <benjamin.bara@...data.com>
---
 drivers/clk/clk.c            | 15 +++++++++++++++
 include/linux/clk-provider.h |  1 +
 2 files changed, 16 insertions(+)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index c249f9791ae8..3e222802b712 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -2462,6 +2462,21 @@ static int clk_core_set_rate_nolock(struct clk_core *core,
 	return ret;
 }
 
+int clk_hw_set_rate(struct clk_hw *hw, unsigned long req_rate)
+{
+	/* A rate change is ongoing, so just target the required rate.
+	 * Note: this does not work if one clock along the line has
+	 * CLK_RECALC_NEW_RATES active, as this overwrites the new_rate again.
+	 */
+	if (hw->core->new_rate != hw->core->rate) {
+		hw->core->new_rate = req_rate;
+		return 0;
+	}
+
+	return clk_core_set_rate_nolock(hw->core, req_rate);
+}
+EXPORT_SYMBOL_GPL(clk_hw_set_rate);
+
 /**
  * clk_set_rate - specify a new rate for clk
  * @clk: the clk whose rate is being changed
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index ec32ec58c59f..3fb99ed5e8d9 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -1316,6 +1316,7 @@ int clk_hw_get_parent_index(struct clk_hw *hw);
 int clk_hw_set_parent(struct clk_hw *hw, struct clk_hw *new_parent);
 unsigned int __clk_get_enable_count(struct clk *clk);
 unsigned long clk_hw_get_rate(const struct clk_hw *hw);
+int clk_hw_set_rate(struct clk_hw *hw, unsigned long req_rate);
 unsigned long clk_hw_get_flags(const struct clk_hw *hw);
 #define clk_hw_can_set_rate_parent(hw) \
 	(clk_hw_get_flags((hw)) & CLK_SET_RATE_PARENT)

-- 
2.34.1