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From:   Heiko Stuebner <heiko@sntech.de>
To:     djw@t-chip.com.cn
Cc:     linux-rockchip@lists.infradead.org, Wayne Chou <zxf@t-chip.com.cn>,
        Michael Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@kernel.org>, linux-kernel@vger.kernel.org,
        linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v0] clk: rockchip: Add pclk_rkpwm_pmu to PMU critical clocks in rk3399
Date:   Mon, 06 Aug 2018 10:10:15 +0200
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Hi Levin,

Am Samstag, 4. August 2018, 09:31:02 CEST schrieb djw@t-chip.com.cn:
> From: Levin Du <djw@t-chip.com.cn>
> 
> PWM2 is commonly used to control voltage of PWM regulator of VDD_LOG in
> RK3399. On the Firefly-RK3399 board, PWM2 outputs 40 KHz square wave
> from power on and the VDD_LOG is about 0.9V. When the kernel boots
> normally into the system, the PWM2 keeps outputing PWM signal.
> 
> But the kernel hangs randomly after "Starting kernel ..." line on that
> board. When it happens, PWM2 outputs high level which causes VDD_LOG
> drops to 0.4V below the normal operating voltage.
> 
> By adding "pclk_rkpwm_pmu" to the rk3399_pmucru_critical_clocks array,
> PWM clock is ensured to be prepared at startup and the PWM2 output is
> normal. After repeated tests, the early boot hang is gone.
> 
> This patch works on both Firefly-RK3399 and ROC-RK3399-PC boards.
> 
> Signed-off-by: Levin Du <djw@t-chip.com.cn>

applied to my clk-branch

Thanks for tracking that down
Heiko