From: broonie@opensource•wolfsonmicro.com (Mark Brown)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] mfd: regulator: max8998: BUCK1/2 control augmented by GPIO pins
Date: Fri, 24 Sep 2010 10:21:24 +0100 [thread overview]
Message-ID: <20100924092123.GG32112@rakim.wolfsonmicro.main> (raw)
In-Reply-To: <20100924110825.138ce87f@lmajewski.digital.local>
On Fri, Sep 24, 2010 at 11:08:25AM +0200, Lukasz Majewski wrote:
> Unfortunately there is problem with this distinction and use of
> gpio_is_valid.
> The gpio_is_valid is simply defined as
> return ((unsigned)number) < ARCH_NR_GPIOS;
> For which 0 is also a valid GPIO.
I understand that on some platforms it is actually a valid GPIO.
> One workaround for this is to check explicitly the condition:
> pdata->buck1_set1 != 0 , but this is neither elegant nor it prevents
> the situation when on some architecture GPIO 0 is valid.
The standard check is gpio_is_valid() with the GPIO set to -1 if it's
not valid.
> is the replacement algorithm. I think that circular buffer
> implementation would be a feasible solution for 4/2 bytes elements
> array.
> With more extended functionality, when more voltage levels would be
> available, more sophisticated approach (like LRU) may be used.
The problem here is that this is going to be pretty pessimal if the
system is using more than four different voltages; you get no advantage
at all from the preprogramming.
prev parent reply other threads:[~2010-09-24 9:21 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-21 14:18 [PATCH] mfd: regulator: max8998: BUCK1/2 control augmented by GPIO pins Lukasz Majewski
2010-09-21 15:01 ` Mark Brown
2010-09-22 6:46 ` Lukasz Majewski
2010-09-22 10:26 ` Mark Brown
2010-09-24 9:08 ` Lukasz Majewski
2010-09-24 9:21 ` Mark Brown [this message]
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