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Subject: Re: [RFC PATCH v2 2/5] leds: add function to configure offload leds
To:     Ansuel Smith <ansuelsmth@gmail.com>, Andrew Lunn <andrew@lunn.ch>,
        Vivien Didelot <vivien.didelot@gmail.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Vladimir Oltean <olteanv@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Jonathan Corbet <corbet@lwn.net>, Pavel Machek <pavel@ucw.cz>,
        John Crispin <john@phrozen.org>, netdev@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-doc@vger.kernel.org, linux-leds@vger.kernel.org
References: <20211108002500.19115-1-ansuelsmth@gmail.com>
 <20211108002500.19115-3-ansuelsmth@gmail.com>
From:   Randy Dunlap <rdunlap@infradead.org>
Message-ID: <f28d4f1b-66e7-808c-ae69-c1734d60fdc1@infradead.org>
Date:   Sun, 7 Nov 2021 18:22:19 -0800
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On 11/7/21 4:24 PM, Ansuel Smith wrote:
> diff --git a/Documentation/leds/leds-class.rst b/Documentation/leds/leds-class.rst
> index 5bf6e5d471ce..0a3bbe71dac7 100644
> --- a/Documentation/leds/leds-class.rst
> +++ b/Documentation/leds/leds-class.rst
> @@ -190,6 +190,30 @@ If the second argument (enable) to the trigger_offload() method is false, any
>   active HW offloading must be deactivated. In this case errors are not permitted
>   in the trigger_offload() method and the driver will be set to the new trigger.
>   
> +The offload trigger will use the function configure_offload() provided by the driver
> +that will configure the offloaded mode for the LED.
> +This function passes as the first argument (offload_flags) a u32 flag.
> +The second argument (cmd) of the configure_offload() method can be used to do various
> +operations for the specific trigger. We currently support ENABLE, DISABLE, READ and
> +SUPPORTED to enable, disable, read the state of the offload trigger and ask the LED
> +driver supports the specific offload trigger.
> +
> +In ENABLE/DISABLE configure_offload() should configure the LED to enable/disable the
> +requested trigger (flags).
> +In READ configure_offload() should return 0 or 1 based on the status of the requested
> +trigger (flags).
> +In SUPPORTED configure_offload() should return 0 or 1 if the LED driver supports the
> +requested trigger (flags) or not.
> +
> +The u32 flag is specific to the trigger and change across them. It's in the LED

                                                changes

> +driver interest know how to elaborate this flag and to declare support for a

    driver's

> +particular offload trigger. For this exact reason explicit support for the specific
> +trigger is mandatory or the driver returns -EOPNOTSUPP if asked to enter offload mode
> +with a not supported trigger.
> +If the driver returns -EOPNOTSUPP on configure_offload(), the trigger activation will
> +fail as the driver doesn't support that specific offload trigger or doesn't know
> +how to handle the provided flags.


-- 
~Randy