linux-kernel - [PATCH V3 2/2] clk: scmi: support state_ctrl

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Date: Mon, 15 Jan 2024 14:02:03 +0800
From: "Peng Fan (OSS)" <peng.fan@....nxp.com>
To: sudeep.holla@....com,
	cristian.marussi@....com,
	mturquette@...libre.com,
	sboyd@...nel.org
Cc: linux-arm-kernel@...ts.infradead.org,
	linux-clk@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Peng Fan <peng.fan@....com>
Subject: [PATCH V3 2/2] clk: scmi: support state_ctrl_forbidden

From: Peng Fan <peng.fan@....com>

Some clocks may exported to linux, while those clocks are not allowed
to configure by Linux. For example:

SYS_CLK1-----
             \
	     --MUX--->MMC1_CLK
             /
SYS_CLK2-----

MMC1 needs set parent, so SYS_CLK1 and SYS_CLK2 are exported to Linux,
then the clk propagation will touch SYS_CLK1 or SYS_CLK2.
So we need bypass the failure for SYS_CLK1 or SYS_CLK2 when enable
the clock of MMC1.

Signed-off-by: Peng Fan <peng.fan@....com>
---

V3:
 Add check in atomic enable

V2:
 New. Take Cristian's suggestion

 drivers/clk/clk-scmi.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/clk-scmi.c b/drivers/clk/clk-scmi.c
index 8cbe24789c24..5327e0547741 100644
--- a/drivers/clk/clk-scmi.c
+++ b/drivers/clk/clk-scmi.c
@@ -119,8 +119,13 @@ static int scmi_clk_determine_rate(struct clk_hw *hw, struct clk_rate_request *r
 static int scmi_clk_enable(struct clk_hw *hw)
 {
 	struct scmi_clk *clk = to_scmi_clk(hw);
+	int ret;
+
+	ret = scmi_proto_clk_ops->enable(clk->ph, clk->id, NOT_ATOMIC);
+	if (ret == -EACCES && clk->info->state_ctrl_forbidden)
+		return 0;
 
-	return scmi_proto_clk_ops->enable(clk->ph, clk->id, NOT_ATOMIC);
+	return ret;
 }
 
 static void scmi_clk_disable(struct clk_hw *hw)
@@ -133,8 +138,13 @@ static void scmi_clk_disable(struct clk_hw *hw)
 static int scmi_clk_atomic_enable(struct clk_hw *hw)
 {
 	struct scmi_clk *clk = to_scmi_clk(hw);
+	int ret;
+
+	ret = scmi_proto_clk_ops->enable(clk->ph, clk->id, ATOMIC);
+	if (ret == -EACCES && clk->info->state_ctrl_forbidden)
+		return 0;
 
-	return scmi_proto_clk_ops->enable(clk->ph, clk->id, ATOMIC);
+	return ret;
 }
 
 static void scmi_clk_atomic_disable(struct clk_hw *hw)
-- 
2.37.1