linux-kernel - Re: [PATCH v7 07/13] slimbus: Add support for 'clock-pause' feature

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Date:   Thu, 23 Nov 2017 07:28:00 +0000
From:   Charles Keepax <ckeepax@...nsource.cirrus.com>
To:     <srinivas.kandagatla@...aro.org>
CC:     <gregkh@...uxfoundation.org>, <broonie@...nel.org>,
        <alsa-devel@...a-project.org>, <sdharia@...eaurora.org>,
        <bp@...e.de>, <poeschel@...onage.de>, <treding@...dia.com>,
        <andreas.noever@...il.com>, <alan@...ux.intel.com>,
        <mathieu.poirier@...aro.org>, <daniel@...ll.ch>, <jkosina@...e.cz>,
        <sharon.dvir1@...l.huji.ac.il>, <joe@...ches.com>,
        <davem@...emloft.net>, <james.hogan@...tec.com>,
        <michael.opdenacker@...e-electrons.com>, <robh+dt@...nel.org>,
        <pawel.moll@....com>, <mark.rutland@....com>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-arm-msm@...r.kernel.org>, <vinod.koul@...el.com>,
        <arnd@...db.de>
Subject: Re: [PATCH v7 07/13] slimbus: Add support for 'clock-pause' feature

On Wed, Nov 15, 2017 at 02:10:37PM +0000, srinivas.kandagatla@...aro.org wrote:
> From: Sagar Dharia <sdharia@...eaurora.org>
> 
> Per slimbus specification, a reconfiguration sequence known as
> 'clock pause' needs to be broadcast over the bus while entering low-
> power mode. Clock-pause is initiated by the controller driver.
> To exit clock-pause, controller typically wakes up the framer device.
> Since wakeup precedure is controller-specific, framework calls it via
> controller's function pointer to invoke it.
> 
> Signed-off-by: Sagar Dharia <sdharia@...eaurora.org>
> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
> ---
> +/**
> + * struct slim_sched: Framework uses this structure internally for scheduling.

Missing kernel doc for clkgear here.

> + * @clk_state: Controller's clock state from enum slim_clk_state
> + * @pause_comp: Signals completion of clock pause sequence. This is useful when
> + *	client tries to call slimbus transaction when controller is entering
> + *	clock pause.
> + * @m_reconf: This mutex is held until current reconfiguration (data channel
> + *	scheduling, message bandwidth reservation) is done. Message APIs can
> + *	use the bus concurrently when this mutex is held since elemental access
> + *	messages can be sent on the bus when reconfiguration is in progress.
> + */
> +struct slim_sched {
> +	int			clkgear;
> +	enum slim_clk_state	clk_state;
> +	struct completion	pause_comp;
> +	struct mutex		m_reconf;
> +};

Thanks,
Charles