linux-kernel - [PATCH v3 1/5] clk: sunxi-ng: common: Support minimum and maximum rate

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Date: Mon, 04 Mar 2024 08:29:17 +0100
From: Frank Oltmanns <frank@...manns.dev>
To: Michael Turquette <mturquette@...libre.com>, 
 Stephen Boyd <sboyd@...nel.org>, Chen-Yu Tsai <wens@...e.org>, 
 Jernej Skrabec <jernej.skrabec@...il.com>, 
 Samuel Holland <samuel@...lland.org>, 
 Guido Günther <agx@...xcpu.org>, 
 Purism Kernel Team <kernel@...i.sm>, Ondrej Jirman <megi@....cz>, 
 Neil Armstrong <neil.armstrong@...aro.org>, 
 Jessica Zhang <quic_jesszhan@...cinc.com>, Sam Ravnborg <sam@...nborg.org>, 
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, 
 David Airlie <airlied@...il.com>, Daniel Vetter <daniel@...ll.ch>, 
 Rob Herring <robh+dt@...nel.org>, 
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>, 
 Conor Dooley <conor+dt@...nel.org>
Cc: linux-clk@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
 linux-sunxi@...ts.linux.dev, linux-kernel@...r.kernel.org, 
 dri-devel@...ts.freedesktop.org, devicetree@...r.kernel.org, 
 Frank Oltmanns <frank@...manns.dev>, stable@...r.kernel.org
Subject: [PATCH v3 1/5] clk: sunxi-ng: common: Support minimum and maximum
 rate

The Allwinner SoC's typically have an upper and lower limit for their
clocks' rates. Up until now, support for that has been implemented
separately for each clock type.

Implement that functionality in the sunxi-ng's common part making use of
the CCF rate liming capabilities, so that it is available for all clock
types.

Suggested-by: Maxime Ripard <mripard@...nel.org>
Signed-off-by: Frank Oltmanns <frank@...manns.dev>
Cc: stable@...r.kernel.org
---
 drivers/clk/sunxi-ng/ccu_common.c | 15 +++++++++++++++
 drivers/clk/sunxi-ng/ccu_common.h |  3 +++
 2 files changed, 18 insertions(+)

diff --git a/drivers/clk/sunxi-ng/ccu_common.c b/drivers/clk/sunxi-ng/ccu_common.c
index 8babce55302f..2152063eee16 100644
--- a/drivers/clk/sunxi-ng/ccu_common.c
+++ b/drivers/clk/sunxi-ng/ccu_common.c
@@ -44,6 +44,12 @@ bool ccu_is_better_rate(struct ccu_common *common,
 			unsigned long current_rate,
 			unsigned long best_rate)
 {
+	if (common->max_rate && current_rate > common->max_rate)
+		return false;
+
+	if (common->min_rate && current_rate < common->min_rate)
+		return false;
+
 	if (common->features & CCU_FEATURE_CLOSEST_RATE)
 		return abs(current_rate - target_rate) < abs(best_rate - target_rate);
 
@@ -122,7 +128,10 @@ static int sunxi_ccu_probe(struct sunxi_ccu *ccu, struct device *dev,
 
 	for (i = 0; i < desc->hw_clks->num ; i++) {
 		struct clk_hw *hw = desc->hw_clks->hws[i];
+		struct ccu_common *common = hw_to_ccu_common(hw);
 		const char *name;
+		unsigned long min_rate = 0;
+		unsigned long max_rate = ULONG_MAX;
 
 		if (!hw)
 			continue;
@@ -136,6 +145,12 @@ static int sunxi_ccu_probe(struct sunxi_ccu *ccu, struct device *dev,
 			pr_err("Couldn't register clock %d - %s\n", i, name);
 			goto err_clk_unreg;
 		}
+
+		if (common->min_rate)
+			min_rate = common->min_rate;
+		if (common->max_rate)
+			max_rate = common->max_rate;
+		clk_hw_set_rate_range(hw, min_rate, max_rate);
 	}
 
 	ret = of_clk_add_hw_provider(node, of_clk_hw_onecell_get,
diff --git a/drivers/clk/sunxi-ng/ccu_common.h b/drivers/clk/sunxi-ng/ccu_common.h
index 942a72c09437..329734f8cf42 100644
--- a/drivers/clk/sunxi-ng/ccu_common.h
+++ b/drivers/clk/sunxi-ng/ccu_common.h
@@ -31,6 +31,9 @@ struct ccu_common {
 	u16		lock_reg;
 	u32		prediv;
 
+	unsigned long	min_rate;
+	unsigned long	max_rate;
+
 	unsigned long	features;
 	spinlock_t	*lock;
 	struct clk_hw	hw;

-- 
2.44.0