Hi Stephen,

-----Original Message-----
From: Stephen Boyd <sboyd@kernel.org>
Sent: Tuesday, October 24, 2023 9:08 AM
To: Buddhabhatti, Jay <redacted>; Simek, Michal
[off-list ref]; mturquette@baylibre.com
Cc: linux-clk@vger.kernel.org; linux-arm-kernel@lists.infradead.org; linux-
kernel@vger.kernel.org; Buddhabhatti, Jay [off-list ref]
Subject: Re: [PATCH RESEND 2/2] drivers: clk: zynqmp: update divider round
rate logic

Quoting Jay Buddhabhatti (2023-10-16 04:30:02)

quoted

Currently zynqmp divider round rate is considering single parent and
calculating rate and parent rate accordingly. But if divider clock
flag is set to SET_RATE_PARENT then its not trying to traverse through
all parent rate and not selecting best parent rate from that. So use
common
divider_round_rate() which is traversing through all clock parents and
its rate and calculating proper parent rate.

Signed-off-by: Jay Buddhabhatti <redacted>
---
 drivers/clk/zynqmp/divider.c | 70
++++++------------------------------
 1 file changed, 10 insertions(+), 60 deletions(-)

Can't argue against removing that many lines!

quoted

diff --git a/drivers/clk/zynqmp/divider.c

b/drivers/clk/zynqmp/divider.c index 33a3b2a22659..a42c183d7e5d 100644

--- a/drivers/clk/zynqmp/divider.c
+++ b/drivers/clk/zynqmp/divider.c

@@ -193,23 +149,17 @@ static long zynqmp_clk_divider_round_rate(struct

clk_hw *hw,

quoted

                return DIV_ROUND_UP_ULL((u64)*prate, bestdiv);
        }

-       bestdiv = zynqmp_divider_get_val(*prate, rate, divider->flags);
-
-       /*
-        * In case of two divisors, compute best divider values and return
-        * divider2 value based on compute value. div1 will  be automatically
-        * set to optimum based on required total divider value.
-        */
-       if (div_type == TYPE_DIV2 &&
-           (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT)) {
-               zynqmp_get_divider2_val(hw, rate, divider, &bestdiv);
+       max = divider->max_div;
+       while (max != 0) {
+               if ((max & 1) == 1)
+                       width++;
+               max = max >> 1;

Is this ffs()?

[Jay] We need last set bit to get max width. I will use fls() to get most significant set bit for this. Thanks for suggestion.

Thanks,
Jay

quoted

        }

-       if ((clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) && divider->is_frac)
-               bestdiv = rate % *prate ? 1 : bestdiv;
+       rate = divider_round_rate(hw, rate, prate, NULL, width,
+ divider->flags);

-       bestdiv = min_t(u32, bestdiv, divider->max_div);
-       *prate = rate * bestdiv;
+       if (divider->is_frac && (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT)

&& (rate % *prate))

quoted

+               *prate = rate;

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