linux-kernel - [PATCH 06/14] clk: qcom: clk-branch: Add support for BRANCH_HALT

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Message-Id: <20241017-sar2130p-clocks-v1-6-f75e740f0a8d@linaro.org>
Date: Thu, 17 Oct 2024 19:56:56 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Bjorn Andersson <andersson@...nel.org>, 
 Michael Turquette <mturquette@...libre.com>, 
 Stephen Boyd <sboyd@...nel.org>, Rob Herring <robh@...nel.org>, 
 Krzysztof Kozlowski <krzk+dt@...nel.org>, 
 Conor Dooley <conor+dt@...nel.org>, Taniya Das <quic_tdas@...cinc.com>, 
 Neil Armstrong <neil.armstrong@...aro.org>, 
 Philipp Zabel <p.zabel@...gutronix.de>, 
 Konrad Dybcio <konradybcio@...nel.org>
Cc: linux-arm-msm@...r.kernel.org, linux-clk@...r.kernel.org, 
 devicetree@...r.kernel.org, linux-kernel@...r.kernel.org, 
 Kalpak Kawadkar <quic_kkawadka@...cinc.com>
Subject: [PATCH 06/14] clk: qcom: clk-branch: Add support for
 BRANCH_HALT_POLL flag

From: Kalpak Kawadkar <quic_kkawadka@...cinc.com>

On some platforms branch clock will be enabled before Linux.
It is expectated from the clock provider is to poll on the clock
to ensure it is indeed enabled and not HW gated, thus add
the BRANCH_HALT_POLL flag.

Signed-off-by: Kalpak Kawadkar <quic_kkawadka@...cinc.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
---
 drivers/clk/qcom/clk-branch.c | 7 ++++++-
 drivers/clk/qcom/clk-branch.h | 1 +
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/qcom/clk-branch.c b/drivers/clk/qcom/clk-branch.c
index 229480c5b075a0e70dc05b1cb15b88d29fd475ce..c4c7bd565cc9a3926e24bb12ed6355ec6ddd19fb 100644
--- a/drivers/clk/qcom/clk-branch.c
+++ b/drivers/clk/qcom/clk-branch.c
@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (c) 2013, The Linux Foundation. All rights reserved.
- * Copyright (c) 2023, Qualcomm Innovation Center, Inc. All rights reserved.
+ * Copyright (c) 2022, 2023 Qualcomm Innovation Center, Inc. All rights reserved.
  */
 
 #include <linux/kernel.h>
@@ -76,6 +76,7 @@ static int clk_branch_wait(const struct clk_branch *br, bool enabling,
 		udelay(10);
 	} else if (br->halt_check == BRANCH_HALT_ENABLE ||
 		   br->halt_check == BRANCH_HALT ||
+		   br->halt_check == BRANCH_HALT_POLL ||
 		   (enabling && voted)) {
 		int count = 200;
 
@@ -97,6 +98,10 @@ static int clk_branch_toggle(struct clk_hw *hw, bool en,
 	struct clk_branch *br = to_clk_branch(hw);
 	int ret;
 
+	if (br->halt_check == BRANCH_HALT_POLL) {
+		return  clk_branch_wait(br, en, check_halt);
+	}
+
 	if (en) {
 		ret = clk_enable_regmap(hw);
 		if (ret)
diff --git a/drivers/clk/qcom/clk-branch.h b/drivers/clk/qcom/clk-branch.h
index 292756435f53648640717734af198442a315272e..47bf59a671c3c8516a57c283fce548a6e5f16619 100644
--- a/drivers/clk/qcom/clk-branch.h
+++ b/drivers/clk/qcom/clk-branch.h
@@ -34,6 +34,7 @@ struct clk_branch {
 #define BRANCH_HALT_ENABLE_VOTED	(BRANCH_HALT_ENABLE | BRANCH_VOTED)
 #define BRANCH_HALT_DELAY		2 /* No bit to check; just delay */
 #define BRANCH_HALT_SKIP		3 /* Don't check halt bit */
+#define BRANCH_HALT_POLL		4 /* Don't enable the clock, poll for halt */
 
 	struct clk_regmap clkr;
 };

-- 
2.39.5