linux-kernel - Re: [PATCH v1 01/10] of: Rename "poweroff-source" property to "system-power-controller"

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Message-ID: <20141027163840.GA14253@saruman>
Date:	Mon, 27 Oct 2014 11:38:40 -0500
From:	Felipe Balbi <balbi@...com>
To:	Romain Perier <romain.perier@...il.com>
CC:	<heiko@...ech.de>, <devicetree@...r.kernel.org>,
	<broonie@...nel.org>, <lgirdwood@...il.com>,
	<linux-kernel@...r.kernel.org>, <grant.likely@...aro.org>,
	<robh@...nel.org>, <mark.rutland@....com>, <johan@...nel.org>,
	<linux-pm@...r.kernel.org>, <linux@...ck-us.net>,
	<lee.jones@...aro.org>, <balbi@...com>, <robh+dt@...nel.org>,
	<pawel.moll@....com>, <ijc+devicetree@...lion.org.uk>,
	<galak@...eaurora.org>, <linux@....linux.org.uk>,
	<swarren@...dotorg.org>, <thierry.reding@...il.com>,
	<gnurou@...il.com>, <linux-arm-kernel@...ts.infradead.org>,
	<linux-tegra@...r.kernel.org>
Subject: Re: [PATCH v1 01/10] of: Rename "poweroff-source" property to
 "system-power-controller"

On Mon, Oct 27, 2014 at 04:26:46PM +0000, Romain Perier wrote:
> As discussed on the mailing list, it makes more sense to rename this property
> to "system-power-controller". Problem being that the word "source" usually tends
> to be used for inputs and that is out of control of the OS. The poweroff
> capability is an output which simply turns the system-power off. Also, this
> property might be used by drivers which power-off the system and power back on
> subsequent RTC alarms. This seems to suggest to remove "poweroff" from the
> property name and to choose "system-power-controller" as the more generic name.
> This patchs adds the required renaming changes and defines an helper function
> which is compatible with both properties, the old one prefixed by a vendor name
> and the new one without any prefix.
> 
> Signed-off-by: Romain Perier <romain.perier@...il.com>
> ---
>  include/linux/of.h | 27 +++++++++++++++++++++++----
>  1 file changed, 23 insertions(+), 4 deletions(-)
> 
> diff --git a/include/linux/of.h b/include/linux/of.h
> index 27b3ba1..c1ed2a5 100644
> --- a/include/linux/of.h
> +++ b/include/linux/of.h
> @@ -867,14 +867,33 @@ static inline int of_changeset_update_property(struct of_changeset *ocs,
>  extern int of_resolve_phandles(struct device_node *tree);
>  
>  /**
> - * of_system_has_poweroff_source - Tells if poweroff-source is found for device_node
> + * of_is_system_power_controller - Tells if the property for controlling system
> + * power is found in device_node.
>   * @np: Pointer to the given device_node
>   *
>   * return true if present false otherwise
>   */
> -static inline bool of_system_has_poweroff_source(const struct device_node *np)
> -{
> -	return of_property_read_bool(np, "poweroff-source");
> +static inline bool of_is_system_power_controller(const struct device_node *np)
> +{
> +	struct property *pp;
> +	unsigned long flags;
> +	char *sep;
> +	bool found = false;
> +
> +	raw_spin_lock_irqsave(&devtree_lock, flags);
> +	for_each_property_of_node(np, pp) {
> +		if (of_prop_cmp(pp->name, "system-power-controller") == 0) {
> +			found = true;
> +			break;
> +		}
> +		sep = strchr(pp->name, ',');
> +		if (sep && sep - pp->name && of_prop_cmp(sep + 1, "system-power-controller") == 0) {
> +			found = true;
> +			break;
> +		}
> +	}
> +	raw_spin_unlock_irqrestore(&devtree_lock, flags);
> +	return found;
>  }
>  
>  #endif /* _LINUX_OF_H */

I think you still need to support poweroff-source since it has been
released on a stable kernel. Perhaps add a warning message telling users
it's deprecated and asking them to switch over to
system-power-controller ? Still, simply removing it isn't very nice.

-- 
balbi

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