linux-kernel - [PATCH V4 2/2] clk: scmi: support state_ctrl

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Date: Sun, 21 Jan 2024 19:09:01 +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 V4 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, adding scmi_no_state_ctrl_clk_ops to use software
enable counter, while not calling scmi api.

Co-developed-by: Cristian Marussi <cristian.marussi@....com>
Signed-off-by: Cristian Marussi <cristian.marussi@....com>
Signed-off-by: Peng Fan <peng.fan@....com>
---

V4:
 Add scmi_no_state_ctrl_clk_ops per Cristian
 Add Cristian's tag

V3:
 Add check in atomic enable

V2:
 New. Take Cristian's suggestion

 drivers/clk/clk-scmi.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/clk-scmi.c b/drivers/clk/clk-scmi.c
index 8cbe24789c24..5747b6d651f0 100644
--- a/drivers/clk/clk-scmi.c
+++ b/drivers/clk/clk-scmi.c
@@ -194,6 +194,15 @@ static const struct clk_ops scmi_atomic_clk_ops = {
 	.determine_rate = scmi_clk_determine_rate,
 };
 
+static const struct clk_ops scmi_no_state_ctrl_clk_ops = {
+	.recalc_rate = scmi_clk_recalc_rate,
+	.round_rate = scmi_clk_round_rate,
+	.set_rate = scmi_clk_set_rate,
+	.set_parent = scmi_clk_set_parent,
+	.get_parent = scmi_clk_get_parent,
+	.determine_rate = scmi_clk_determine_rate,
+};
+
 static int scmi_clk_ops_init(struct device *dev, struct scmi_clk *sclk,
 			     const struct clk_ops *scmi_ops)
 {
@@ -290,8 +299,10 @@ static int scmi_clocks_probe(struct scmi_device *sdev)
 		 * specify (or support) an enable_latency associated with a
 		 * clock, we default to use atomic operations mode.
 		 */
-		if (is_atomic &&
-		    sclk->info->enable_latency <= atomic_threshold)
+		if (sclk->info->state_ctrl_forbidden)
+			scmi_ops = &scmi_no_state_ctrl_clk_ops;
+		else if (is_atomic &&
+			 sclk->info->enable_latency <= atomic_threshold)
 			scmi_ops = &scmi_atomic_clk_ops;
 		else
 			scmi_ops = &scmi_clk_ops;
-- 
2.37.1