linux-kernel - [PATCH] drivers: clk: zynqmp: Allow zero divisor value

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Date:   Mon, 4 Mar 2019 15:27:46 -0800
From:   Jolly Shah <jolly.shah@...inx.com>
To:     <mturquette@...libre.com>, <sboyd@...eaurora.org>,
        <michal.simek@...inx.com>, <linux-clk@...r.kernel.org>
CC:     <rajanv@...inx.com>, <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, Rajan Vaja <rajan.vaja@...inx.com>,
        Jolly Shah <jollys@...inx.com>
Subject: [PATCH] drivers: clk: zynqmp: Allow zero divisor value

From: Rajan Vaja <rajan.vaja@...inx.com>

Zero divider is valid and default for some of ZynqMP
clocks. Allow zero divisor when CLK_DIVIDER_ALLOW_ZERO
for the clock is set.

Signed-off-by: Rajan Vaja <rajanv@...inx.com>
Signed-off-by: Jolly Shah <jollys@...inx.com>
---
 drivers/clk/zynqmp/divider.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/clk/zynqmp/divider.c b/drivers/clk/zynqmp/divider.c
index a371c66..e146b6f 100644
--- a/drivers/clk/zynqmp/divider.c
+++ b/drivers/clk/zynqmp/divider.c
@@ -76,6 +76,13 @@ static unsigned long zynqmp_clk_divider_recalc_rate(struct clk_hw *hw,
 	else
 		value = div >> 16;
 
+	if (!value) {
+		WARN(!(divider->flags & CLK_DIVIDER_ALLOW_ZERO),
+		     "%s: Zero divisor and CLK_DIVIDER_ALLOW_ZERO not set\n",
+		     clk_name);
+		return parent_rate;
+	}
+
 	return DIV_ROUND_UP_ULL(parent_rate, value);
 }
 
-- 
2.7.4