linux-kernel - Re: [PATCH v6 2/6] ARM: imx6: register pm_power_off handler if "fsl,pmic-stby-poweroff" is set

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Date:   Tue, 8 May 2018 13:40:33 +0100
From:   Russell King - ARM Linux <linux@...linux.org.uk>
To:     Oleksij Rempel <o.rempel@...gutronix.de>
Cc:     Shawn Guo <shawnguo@...nel.org>, Mark Brown <broonie@...nel.org>,
        kernel@...gutronix.de, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-clk@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Andrew Morton <akpm@...ux-foundation.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        Leonard Crestez <leonard.crestez@....com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...eaurora.org>,
        Fabio Estevam <fabio.estevam@....com>
Subject: Re: [PATCH v6 2/6] ARM: imx6: register pm_power_off handler if
 "fsl,pmic-stby-poweroff" is set

On Mon, Mar 05, 2018 at 11:25:19AM +0100, Oleksij Rempel wrote:
> One of the Freescale recommended sequences for power off with external
> PMIC is the following:
> ...
> 3.  SoC is programming PMIC for power off when standby is asserted.
> 4.  In CCM STOP mode, Standby is asserted, PMIC gates SoC supplies.
> 
> See:
> http://www.nxp.com/assets/documents/data/en/reference-manuals/IMX6DQRM.pdf
> page 5083
> 
> This patch implements step 4. of this sequence.
> 
> Signed-off-by: Oleksij Rempel <o.rempel@...gutronix.de>
> ---
>  arch/arm/mach-imx/pm-imx6.c | 25 +++++++++++++++++++++++++
>  1 file changed, 25 insertions(+)
> 
> diff --git a/arch/arm/mach-imx/pm-imx6.c b/arch/arm/mach-imx/pm-imx6.c
> index ecdf071653d4..24689260a2a5 100644
> --- a/arch/arm/mach-imx/pm-imx6.c
> +++ b/arch/arm/mach-imx/pm-imx6.c
> @@ -604,6 +604,28 @@ static void __init imx6_pm_common_init(const struct imx6_pm_socdata
>  				   IMX6Q_GPR1_GINT);
>  }
>  
> +static void imx6_pm_stby_poweroff(void)
> +{
> +	imx6_set_lpm(STOP_POWER_OFF);
> +	cpu_suspend(0, imx6q_suspend_finish);

Do you actually need to save the processor state etc here - the request
is after all to power down the system and not to suspend.  Would calling
imx6q_suspend_finish() directly work (and hence simplify the code) ?

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
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