From: andrew@lunn.ch (Andrew Lunn)
Date: Fri, 24 Oct 2014 22:45:32 +0200
Subject: [PATCH 06/17] gpio: mvebu: add suspend/resume support
In-Reply-To: <20141024163051.GG4529@psi-dev26.jf.intel.com>
References: <1414151970-6626-1-git-send-email-thomas.petazzoni@free-electrons.com>
 <1414151970-6626-7-git-send-email-thomas.petazzoni@free-electrons.com>
 <20141024163051.GG4529@psi-dev26.jf.intel.com>
Message-ID: <20141024204532.GA6436@lunn.ch>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

> > +	switch (mvchip->soc_variant) {
> > +	case MVEBU_GPIO_SOC_VARIANT_ORION:
> > +		mvchip->edge_mask_regs[0] =
> > +			readl(mvchip->membase + GPIO_EDGE_MASK_OFF);
> > +		mvchip->level_mask_regs[0] =
> > +			readl(mvchip->membase + GPIO_LEVEL_MASK_OFF);
> > +		break;
> > +	case MVEBU_GPIO_SOC_VARIANT_MV78200:
> > +		for (i = 0; i < 2; i++) {
> > +			mvchip->edge_mask_regs[i] =
> > +				readl(mvchip->membase +
> > +				      GPIO_EDGE_MASK_MV78200_OFF(i));
> > +			mvchip->level_mask_regs[i] =
> > +				readl(mvchip->membase +
> > +				      GPIO_LEVEL_MASK_MV78200_OFF(i));
> > +		}
> > +		break;
> > +	case MVEBU_GPIO_SOC_VARIANT_ARMADAXP:
> > +		for (i = 0; i < 4; i++) {
> > +			mvchip->edge_mask_regs[i] =
> > +				readl(mvchip->membase +
> > +				      GPIO_EDGE_MASK_ARMADAXP_OFF(i));
> > +			mvchip->level_mask_regs[i] =
> > +				readl(mvchip->membase +
> > +				      GPIO_LEVEL_MASK_ARMADAXP_OFF(i));
> > +		}
> > +		break;
> > +	default:
> > +		BUG();
> 
> Isn't it too severe? Is the platform going too unstable if driver
> reaches this case?
> I'd consider a WARN() instead.

This is a common pattern in this driver. So i guess Thomas just
cut/pasted the switch statement from _probe(), which also has the
BUG().

Given that _probe() should of thrown a BUG() in this situation, if it
happens here, it means mvchip->soc_variant has been corrupted, and so
bad things are happening. So a BUG() is maybe called for?

	 Andrew