Patch "clk: qcom: clk-rcg2: Make sure to not write d=0 to the NMD register" has been added to the 5.18-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

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

    clk: qcom: clk-rcg2: Make sure to not write d=0 to the NMD register

to the 5.18-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:
     clk-qcom-clk-rcg2-make-sure-to-not-write-d-0-to-the-.patch
and it can be found in the queue-5.18 subdirectory.

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



commit 5ed9da11a435a8e476deda55e08d5c5644f11390
Author: Nikita Travkin <nikita@xxxxxxx>
Date:   Sun Jun 12 19:59:53 2022 +0500

    clk: qcom: clk-rcg2: Make sure to not write d=0 to the NMD register
    
    [ Upstream commit d0696770cef35a1fd16ea2167e2198c18aa6fbfe ]
    
    Sometimes calculation of d value may result in 0 because of the
    rounding after integer division. This causes the following error:
    
    [  113.969689] camss_gp1_clk_src: rcg didn't update its configuration.
    [  113.969754] WARNING: CPU: 3 PID: 35 at drivers/clk/qcom/clk-rcg2.c:122 update_config+0xc8/0xdc
    
    Make sure that D value is never zero.
    
    Fixes: 7f891faf596e ("clk: qcom: clk-rcg2: Add support for duty-cycle for RCG")
    Signed-off-by: Nikita Travkin <nikita@xxxxxxx>
    Reviewed-by: Stephen Boyd <sboyd@xxxxxxxxxx>
    Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/20220612145955.385787-3-nikita@xxxxxxx
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/clk/qcom/clk-rcg2.c b/drivers/clk/qcom/clk-rcg2.c
index 9611c9a7231f..caafc35eecfd 100644
--- a/drivers/clk/qcom/clk-rcg2.c
+++ b/drivers/clk/qcom/clk-rcg2.c
@@ -13,6 +13,7 @@
 #include <linux/rational.h>
 #include <linux/regmap.h>
 #include <linux/math64.h>
+#include <linux/minmax.h>
 #include <linux/slab.h>
 
 #include <asm/div64.h>
@@ -429,9 +430,11 @@ static int clk_rcg2_set_duty_cycle(struct clk_hw *hw, struct clk_duty *duty)
 	/* Calculate 2d value */
 	d = DIV_ROUND_CLOSEST(n * duty_per * 2, 100);
 
-	 /* Check bit widths of 2d. If D is too big reduce duty cycle. */
-	if (d > mask)
-		d = mask;
+	/*
+	 * Check bit widths of 2d. If D is too big reduce duty cycle.
+	 * Also make sure it is never zero.
+	 */
+	d = clamp_val(d, 1, mask);
 
 	if ((d / 2) > (n - m))
 		d = (n - m) * 2;