linux-kernel - Re: [PATCH 3/3] mmc: sdhci: apply voltage range check only for non-fixed regulators

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Message-ID: <87fw4dn030.fsf@octavius.laptop.org>
Date:	Tue, 13 Nov 2012 07:45:07 -0500
From:	Chris Ball <cjb@...top.org>
To:	Marek Szyprowski <m.szyprowski@...sung.com>
Cc:	linux-kernel@...r.kernel.org, linux-mmc@...r.kernel.org,
	Kyungmin Park <kyungmin.park@...sung.com>,
	Mark Brown <broonie@...nsource.wolfsonmicro.com>,
	Liam Girdwood <lrg@...com>
Subject: Re: [PATCH 3/3] mmc: sdhci: apply voltage range check only for non-fixed regulators

Hi Marek,

On Tue, Nov 13 2012, Marek Szyprowski wrote:
> Fixed regulators cannot change their voltage, so disable all voltage range
> checking for them, otherwise the driver fails to operate with fixed
> regulators.
>
> Signed-off-by: Marek Szyprowski <m.szyprowski@...sung.com>

Perhaps it's a good idea to mention that the regulator API is changing
(being fixed) at the same time, and that's why this patch is necessary.

> ---
>  drivers/mmc/host/sdhci.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index c7851c0..6f6534e 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -2923,7 +2923,7 @@ int sdhci_add_host(struct sdhci_host *host)
>  		regulator_enable(host->vmmc);
>  
>  #ifdef CONFIG_REGULATOR
> -	if (host->vmmc) {
> +	if (host->vmmc && regulator_count_voltages(host->vmmc) > 1) {
>  		ret = regulator_is_supported_voltage(host->vmmc, 3300000,
>  			3300000);
>  		if ((ret <= 0) || (!(caps[0] & SDHCI_CAN_VDD_330)))

What about other occasions where is_supported_voltage() is used, like
this one -- is it necessary here too?

        else if (regulator_is_supported_voltage(host->vqmmc, 1800000, 1800000))
                regulator_enable(host->vqmmc);

Thanks,                

- Chris.
-- 
Chris Ball   <cjb@...top.org>   <http://printf.net/>
One Laptop Per Child
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