linux-kernel - [PATCH 2/6 v6] clk, highbank: Prevent glitches in non-bypass reset mode

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Message-Id: <1354046672-7392-3-git-send-email-mark.langsdorf@calxeda.com>
Date:	Tue, 27 Nov 2012 14:04:28 -0600
From:	Mark Langsdorf <mark.langsdorf@...xeda.com>
To:	linux-kernel@...r.kernel.org, cpufreq@...r.kernel.org,
	linux-pm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Cc:	Mark Langsdorf <mark.langsdorf@...xeda.com>,
	Rob Herring <rob.herring@...xeda.com>
Subject: [PATCH 2/6 v6] clk, highbank: Prevent glitches in non-bypass reset mode

The highbank clock will glitch with the current code if the
clock rate is reset without relocking the PLL. Program the PLL
correctly to prevent glitches.

Signed-off-by: Mark Langsdorf <mark.langsdorf@...xeda.com>
Signed-off-by: Rob Herring <rob.herring@...xeda.com>
Acked-by: Mike Turquette <mturquette@...aro.org>
---
Changes from v5
	Added Mike Turquette's ack.
Changes from v4
        None.
Changes from v3
        Changelog text and patch name now correspond to the actual patch.
        was clk, highbank: remove non-bypass reset mode.
Changes from v2
        None.
Changes from v1:
        Removed erroneous reformating.

 drivers/clk/clk-highbank.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/clk/clk-highbank.c b/drivers/clk/clk-highbank.c
index 52fecad..3a0b723 100644
--- a/drivers/clk/clk-highbank.c
+++ b/drivers/clk/clk-highbank.c
@@ -182,8 +182,10 @@ static int clk_pll_set_rate(struct clk_hw *hwclk, unsigned long rate,
 		reg |= HB_PLL_EXT_ENA;
 		reg &= ~HB_PLL_EXT_BYPASS;
 	} else {
+		writel(reg | HB_PLL_EXT_BYPASS, hbclk->reg);
 		reg &= ~HB_PLL_DIVQ_MASK;
 		reg |= divq << HB_PLL_DIVQ_SHIFT;
+		writel(reg | HB_PLL_EXT_BYPASS, hbclk->reg);
 	}
 	writel(reg, hbclk->reg);
 
-- 
1.7.11.7

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