Patch "soc: imx8m: Enable OCOTP clock before reading the register" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    soc: imx8m: Enable OCOTP clock before reading the register

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     soc-imx8m-enable-ocotp-clock-before-reading-the-regi.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 232226dcd3c242ccf54cce8707b1c797ce3fe649
Author: Xiaolei Wang <xiaolei.wang@xxxxxxxxxxxxx>
Date:   Fri Oct 28 12:14:18 2022 +0800

    soc: imx8m: Enable OCOTP clock before reading the register
    
    [ Upstream commit 836fb30949d9edf91d7de696a884ceeae7e426d2 ]
    
    Commit 7d981405d0fd ("soc: imx8m: change to use platform driver") ever
    removed the dependency on bootloader for enabling OCOTP clock.  It
    helped to fix a kexec kernel hang issue.  But unfortunately it caused
    a regression on CAAM driver and got reverted.
    
    This is the second try to enable the OCOTP clock by directly calling
    clock API instead of indirectly enabling the clock via nvmem API.
    
    Fixes: ac34de14ac30 ("Revert "soc: imx8m: change to use platform driver"")
    Signed-off-by: Xiaolei Wang <xiaolei.wang@xxxxxxxxxxxxx>
    Reviewed-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
    Signed-off-by: Shawn Guo <shawnguo@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/soc/imx/soc-imx8m.c b/drivers/soc/imx/soc-imx8m.c
index cc57a384d74d..28144c699b0c 100644
--- a/drivers/soc/imx/soc-imx8m.c
+++ b/drivers/soc/imx/soc-imx8m.c
@@ -11,6 +11,7 @@
 #include <linux/platform_device.h>
 #include <linux/arm-smccc.h>
 #include <linux/of.h>
+#include <linux/clk.h>
 
 #define REV_B1				0x21
 
@@ -56,6 +57,7 @@ static u32 __init imx8mq_soc_revision(void)
 	void __iomem *ocotp_base;
 	u32 magic;
 	u32 rev;
+	struct clk *clk;
 
 	np = of_find_compatible_node(NULL, NULL, "fsl,imx8mq-ocotp");
 	if (!np)
@@ -63,6 +65,13 @@ static u32 __init imx8mq_soc_revision(void)
 
 	ocotp_base = of_iomap(np, 0);
 	WARN_ON(!ocotp_base);
+	clk = of_clk_get_by_name(np, NULL);
+	if (!clk) {
+		WARN_ON(!clk);
+		return 0;
+	}
+
+	clk_prepare_enable(clk);
 
 	/*
 	 * SOC revision on older imx8mq is not available in fuses so query
@@ -79,6 +88,8 @@ static u32 __init imx8mq_soc_revision(void)
 	soc_uid <<= 32;
 	soc_uid |= readl_relaxed(ocotp_base + OCOTP_UID_LOW);
 
+	clk_disable_unprepare(clk);
+	clk_put(clk);
 	iounmap(ocotp_base);
 	of_node_put(np);