linux-kernel - [PATCH v3 5/5] clk: imx: lpcg-scu: Skip HDMI LPCG clock save/restore

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Message-Id: <20241027-imx-clk-v1-v3-5-89152574d1d7@nxp.com>
Date: Sun, 27 Oct 2024 20:00:11 +0800
From: "Peng Fan (OSS)" <peng.fan@....nxp.com>
To: Abel Vesa <abelvesa@...nel.org>, 
 Michael Turquette <mturquette@...libre.com>, 
 Stephen Boyd <sboyd@...nel.org>, Shawn Guo <shawnguo@...nel.org>, 
 Sascha Hauer <s.hauer@...gutronix.de>, 
 Pengutronix Kernel Team <kernel@...gutronix.de>, 
 Fabio Estevam <festevam@...il.com>, Aisheng Dong <aisheng.dong@....com>
Cc: linux-clk@...r.kernel.org, imx@...ts.linux.dev, 
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org, 
 Abel Vesa <abel.vesa@...aro.org>, Peng Fan <peng.fan@....com>
Subject: [PATCH v3 5/5] clk: imx: lpcg-scu: Skip HDMI LPCG clock
 save/restore

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

On i.MX8QM, HDMI LPCG clocks operation needs SCU clock "hdmi_ipg_clk"
to be ON. While during noirq suspend phase, "hdmi_ipg_clk" is disabled
by HDMI IRQ STEER driver, so SError will be triggered when accessing
the HDMI LPCG registers.

Skip all HDMI LPCG clocks save/restore to avoid SError during
system suspend/resume, it will NOT introduce additional power consumption
as their parent clock is disabled when suspend.

Signed-off-by: Peng Fan <peng.fan@....com>
---
 drivers/clk/imx/clk-lpcg-scu.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/clk/imx/clk-lpcg-scu.c b/drivers/clk/imx/clk-lpcg-scu.c
index 620afdf8dc03e9564bb074ca879cf778f7fc6419..6376557a3c3d03130ca8168a6cb69eda73c43abe 100644
--- a/drivers/clk/imx/clk-lpcg-scu.c
+++ b/drivers/clk/imx/clk-lpcg-scu.c
@@ -161,6 +161,9 @@ static int __maybe_unused imx_clk_lpcg_scu_suspend(struct device *dev)
 {
 	struct clk_lpcg_scu *clk = dev_get_drvdata(dev);
 
+	if (!strncmp("hdmi_lpcg", clk_hw_get_name(&clk->hw), strlen("hdmi_lpcg")))
+		return 0;
+
 	clk->state = readl_relaxed(clk->reg);
 	dev_dbg(dev, "save lpcg state 0x%x\n", clk->state);
 
@@ -171,6 +174,9 @@ static int __maybe_unused imx_clk_lpcg_scu_resume(struct device *dev)
 {
 	struct clk_lpcg_scu *clk = dev_get_drvdata(dev);
 
+	if (!strncmp("hdmi_lpcg", clk_hw_get_name(&clk->hw), strlen("hdmi_lpcg")))
+		return 0;
+
 	writel(clk->state, clk->reg);
 	lpcg_e10858_writel(0, clk->reg, clk->state);
 	dev_dbg(dev, "restore lpcg state 0x%x\n", clk->state);

-- 
2.37.1