linux-kernel - Re: [PATCH] power: supply: max8903: configure USUS as output

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Date: Tue, 30 Apr 2024 16:33:16 +0200
From: Sebastian Reichel <sebastian.reichel@...labora.com>
To: Herman van Hazendonk <github.com@...rie.org>
Cc: linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Ben Wolsieffer <benwolsieffer@...il.com>, Linus Walleij <linus.walleij@...aro.org>
Subject: Re: [PATCH] power: supply: max8903: configure USUS as output

Hi,

On Wed, Apr 17, 2024 at 03:35:00PM +0200, Herman van Hazendonk wrote:
> The USUS pin was mistakenly configured as an input, when it should be an
> output that specifies whether the USB power input is suspended. In addition
> to fixing the pin mode, this patch also suspends the USB input when a DC
> charger is connected, which should result in a slight reduction in USB
> quiescent current.
> 
> Signed-off-by: Ben Wolsieffer <benwolsieffer@...il.com>
> Signed-off-by: Herman van Hazendonk <github.com@...rie.org>
> ---

Thanks for your patch. I think this should get

Fixes: 50da8d04ee52 ("power: supply: max8903: Convert to GPIO descriptors")

Also what's going on with the Signed-off-by? Did you forward the
patch from Ben Wolsieffer (i.e. the author is wrong) or did you
co-develop it (so there should be a "Co-developed-by: Ben Wolsieffer
<benwolsieffer@...il.com>" tag)?

>  drivers/power/supply/max8903_charger.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/power/supply/max8903_charger.c b/drivers/power/supply/max8903_charger.c
> index e65d0141f260..15dc3a5239e2 100644
> --- a/drivers/power/supply/max8903_charger.c
> +++ b/drivers/power/supply/max8903_charger.c
> @@ -102,6 +102,10 @@ static irqreturn_t max8903_dcin(int irq, void *_data)
>  	if (data->dcm)
>  		gpiod_set_value(data->dcm, ta_in);
>  
> +	/* Set USB-Suspend 1:Suspended 0:Active */
> +	if (data->usus)
> +		gpiod_set_value(data->usus, ta_in);
> +
>  	/* Charger Enable / Disable */
>  	if (data->cen) {
>  		int val;
> @@ -310,7 +314,15 @@ static int max8903_setup_gpios(struct platform_device *pdev)
>  				     "failed to get FLT GPIO");
>  	gpiod_set_consumer_name(data->flt, data->psy_desc.name);
>  
> -	data->usus = devm_gpiod_get_optional(dev, "usus", GPIOD_IN);
> +	/*
> +	 * Suspend the USB input if the DC charger is connected.
> +	 *
> +	 * The USUS line should be marked GPIO_ACTIVE_HIGH in the
> +	 * device tree. Driving it low will enable the USB charger
> +	 * input.

I think the above 3 lines should be dropped. They added more
confusion to me than actually helping and the information is
already in the DT binding file.

Greetings,

-- Sebastian

> +	 */
> +	flags = ta_in ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
> +	data->usus = devm_gpiod_get_optional(dev, "usus", flags);
>  	if (IS_ERR(data->usus))
>  		return dev_err_probe(dev, PTR_ERR(data->usus),
>  				     "failed to get USUS GPIO");
> 
> ---
> base-commit: 96fca68c4fbf77a8185eb10f7557e23352732ea2
> change-id: 20240417-max8903-ace97d7d3407
> 
> Best regards,
> -- 
> Herman van Hazendonk <github.com@...rie.org>
> 

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