linux-kernel - Re: [PATCH] regulator: core: silence warning: "VDD1: ramp

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Message-ID: <20161027174109.GA185131@google.com>
Date:   Thu, 27 Oct 2016 10:41:09 -0700
From:   Matthias Kaehlcke <mka@...omium.org>
To:     "H. Nikolaus Schaller" <hns@...delico.com>
Cc:     linux-kernel@...r.kernel.org, Mark Brown <broonie@...nel.org>,
        letux-kernel@...nphoenux.org
Subject: Re: [PATCH] regulator: core: silence warning: "VDD1: ramp_delay not
 set"

El Thu, Oct 27, 2016 at 02:31:39PM +0200 H. Nikolaus Schaller ha dit:

> commit 73e705bf81ce ("regulator: core: Add set_voltage_time op")
> 
> introduced a new rdev_warn() if the ramp_delay is 0.
> 
> Apparently, on omap3/twl4030 platforms with dynamic voltage
> management this results in non-ending spurious messages like
> 
> [  511.143066] VDD1: ramp_delay not set
> [  511.662322] VDD1: ramp_delay not set
> [  513.903625] VDD1: ramp_delay not set
> [  514.222198] VDD1: ramp_delay not set
> [  517.062835] VDD1: ramp_delay not set
> [  517.382568] VDD1: ramp_delay not set
> [  520.142791] VDD1: ramp_delay not set
> [  520.502593] VDD1: ramp_delay not set
> [  523.062896] VDD1: ramp_delay not set
> [  523.362701] VDD1: ramp_delay not set
> [  526.143035] VDD1: ramp_delay not set
> 
> I have observed this on GTA04 while it is reported to occur on
> N900 as well: https://bugzilla.kernel.org/show_bug.cgi?id=178371
> 
> This patch makes the warning appear only in debugging mode.
> 
> Signed-off-by: H. Nikolaus Schaller <hns@...delico.com>
> ---
>  drivers/regulator/core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
> index 67426c0..5c1519b 100644
> --- a/drivers/regulator/core.c
> +++ b/drivers/regulator/core.c
> @@ -2754,7 +2754,7 @@ static int _regulator_set_voltage_time(struct regulator_dev *rdev,
>  		ramp_delay = rdev->desc->ramp_delay;
>  
>  	if (ramp_delay == 0) {
> -		rdev_warn(rdev, "ramp_delay not set\n");
> +		rdev_dbg(rdev, "ramp_delay not set\n");
>  		return 0;
>  	}

Sorry about that, I didn't run into this since in my tests ramp_delay
was set :(

Calling _regulator_set_voltage_time() with ramp_delay being zero is
a common case, I think the message should be removed completely.

Thanks

Matthias