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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Codrin Ciubotariu <codrin.ciubotariu@microchip.com>,
        Nicolas Ferre <nicolas.ferre@microchip.com>,
        Ludovic Desroches <ludovic.desroches@microchip.com>,
        Stephen Boyd <sboyd@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.2 039/135] clk: at91: generated: Truncate divisor to GENERATED_MAX_DIV + 1
Date:   Thu, 22 Aug 2019 13:06:35 -0400
Message-Id: <20190822170811.13303-40-sashal@kernel.org>
In-Reply-To: <20190822170811.13303-1-sashal@kernel.org>
References: <20190822170811.13303-1-sashal@kernel.org>
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From: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>

[ Upstream commit 1573eebeaa8055777eb753f9b4d1cbe653380c38 ]

In clk_generated_determine_rate(), if the divisor is greater than
GENERATED_MAX_DIV + 1, then the wrong best_rate will be returned.
If clk_generated_set_rate() will be called later with this wrong
rate, it will return -EINVAL, so the generated clock won't change
its value. Do no let the divisor be greater than GENERATED_MAX_DIV + 1.

Fixes: 8c7aa6328947 ("clk: at91: clk-generated: remove useless divisor loop")
Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/clk/at91/clk-generated.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/clk/at91/clk-generated.c b/drivers/clk/at91/clk-generated.c
index 44db83a6d01c2..44a46dcc0518b 100644
--- a/drivers/clk/at91/clk-generated.c
+++ b/drivers/clk/at91/clk-generated.c
@@ -141,6 +141,8 @@ static int clk_generated_determine_rate(struct clk_hw *hw,
 			continue;
 
 		div = DIV_ROUND_CLOSEST(parent_rate, req->rate);
+		if (div > GENERATED_MAX_DIV + 1)
+			div = GENERATED_MAX_DIV + 1;
 
 		clk_generated_best_diff(req, parent, parent_rate, div,
 					&best_diff, &best_rate);
-- 
2.20.1