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From:   Katsuhiro Suzuki <katsuhiro@katsuster.net>
To:     Michael Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@kernel.org>, linux-clk@vger.kernel.org
Cc:     linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Katsuhiro Suzuki <katsuhiro@katsuster.net>
Subject: [PATCH] clk: fractional-divider: check parent rate only for general approximation
Date:   Mon,  7 Jan 2019 22:21:24 +0900
Message-Id: <20190107132124.27788-1-katsuhiro@katsuster.net>
MIME-Version: 1.0
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Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Custom approximation of fractional-divider may not need parent clock
rate checking. For example Rockchip SoCs work fine using grand parent
clock rate evne if target rate is greater than parent.

This patch removes parent clock rate check from custom approximation.

Signed-off-by: Katsuhiro Suzuki <katsuhiro@katsuster.net>
---
 drivers/clk/clk-fractional-divider.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/clk/clk-fractional-divider.c b/drivers/clk/clk-fractional-divider.c
index 545dceec0bbf..b0fc5509e0ff 100644
--- a/drivers/clk/clk-fractional-divider.c
+++ b/drivers/clk/clk-fractional-divider.c
@@ -79,13 +79,17 @@ static long clk_fd_round_rate(struct clk_hw *hw, unsigned long rate,
 	unsigned long m, n;
 	u64 ret;
 
-	if (!rate || rate >= *parent_rate)
+	if (!rate)
 		return *parent_rate;
 
-	if (fd->approximation)
+	if (fd->approximation) {
 		fd->approximation(hw, rate, parent_rate, &m, &n);
-	else
+	} else {
+		if (rate >= *parent_rate)
+			return *parent_rate;
+
 		clk_fd_general_approximation(hw, rate, parent_rate, &m, &n);
+	}
 
 	ret = (u64)*parent_rate * m;
 	do_div(ret, n);
-- 
2.20.1