linux-kernel - regulator: ab8500-ext: Strange set_mode behavior when info->cfg->hwreq is set

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Message-ID: <1365519681.3946.4.camel@phoenix>
Date:	Tue, 09 Apr 2013 23:01:21 +0800
From:	Axel Lin <axel.lin@...ics.com>
To:	Mark Brown <broonie@...nsource.wolfsonmicro.com>
Cc:	Bengt Jonsson <bengt.g.jonsson@...ricsson.com>,
	Lee Jones <lee.jones@...aro.org>,
	Yvan FILLION <yvan.fillion@...ricsson.com>,
	Liam Girdwood <lgirdwood@...il.com>,
	linux-kernel@...r.kernel.org
Subject: regulator: ab8500-ext: Strange set_mode behavior when
 info->cfg->hwreq is set

Hi,

I see below code && comments in enable() function:

        /*
         * To satisfy both HW high power request and SW request, the regulator
         * must be on in high power.
         */
        if (info->cfg && info->cfg->hwreq)
                *regval = info->update_val_hp;

I'm not very clear about the comment and the code.

1) Does that mean the device does not allow set REGULATOR_MODE_IDLE when
info->cfg->hwreq is set?

current code looks strange because when info->cfg->hwreq is set:
set_mode() allows set REGULATOR_MODE_IDLE and get_mode() returns the status
is REGULATOR_MODE_IDLE. However, current code actually write info->update_val_hp
to the register (which means it is in REGULATOR_MODE_NORMAL mode).

If the device does not allow set REGULATOR_MODE_IDLE when info->cfg->hwreq is 
set, we probably needs to return error in set REGULATOR_MODE_IDLE case.

Or 2) Does above comment mean the device needs set to REGULATOR_MODE_NORMAL
when the regulator is switching from off to on? Which means it allows setting
the regulator to REGULATOR_MODE_IDLE if the regulator is already on.

If this is the case, we cannot call enable() in set_mode() because current code
in set_mode() will write to register only when the regulator is already on.
Calling enable() always write info->update_val_hp to the register.
Thus it should just call abx500_mask_and_set_register_interruptible() directly
to update the register.

comments?

Regards,
Axel

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