Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Tue, 29 Jan 2019 09:54:38 +0000
From:   Charles Keepax <ckeepax@opensource.cirrus.com>
To:     Axel Lin <axel.lin@ingics.com>
CC:     Mark Brown <broonie@kernel.org>,
        Liam Girdwood <lgirdwood@gmail.com>,
        <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] regulator: lochnagar: Fix n_voltages setting for VDDCORE
Message-ID: <20190129095438.GJ3837@imbe.wolfsonmicro.main>
References: <20190129030156.2024-1-axel.lin@ingics.com>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Disposition: inline
In-Reply-To: <20190129030156.2024-1-axel.lin@ingics.com>
User-Agent: Mutt/1.5.20 (2009-12-10)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Tue, Jan 29, 2019 at 11:01:56AM +0800, Axel Lin wrote:
> With current n_voltages setting, regulator_list_voltage will return
> -EINVAL when selector >=57. The highest selector is 0x41, so the
> n_voltages should be 0x41+1, i.e. 66.
> 
> Signed-off-by: Axel Lin <axel.lin@ingics.com>
> ---
>  drivers/regulator/lochnagar-regulator.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/regulator/lochnagar-regulator.c b/drivers/regulator/lochnagar-regulator.c
> index 4962d13659aa..ff97cc50f2eb 100644
> --- a/drivers/regulator/lochnagar-regulator.c
> +++ b/drivers/regulator/lochnagar-regulator.c
> @@ -194,7 +194,7 @@ static const struct regulator_desc lochnagar_regulators[] = {
>  		.name = "VDDCORE",
>  		.supply_name = "SYSVDD",
>  		.type = REGULATOR_VOLTAGE,
> -		.n_voltages = 57,
> +		.n_voltages = 66,
>  		.ops = &lochnagar_vddcore_ops,
>  
>  		.id = LOCHNAGAR_VDDCORE,
> -- 
> 2.17.1

Hmm... I think this might need a little more investigation, it
does indeed fail at present (amazing that it works upto exactly 1.2V
which is common the usecase) but this feels more like a core
problem. There are indeed only 57 valid voltage settings as the
range is 0x8 - 0x41, but it seems that presently the core treats
this less as n_voltages and more like max_selector. Should we
perhaps be teaching the core to understand the min_selector
instead?

Thanks,
Charles