linux-kernel - Re: [PATCH] soc: mediatek: PMIC wrap: Clear the vldclr if state machine is stay on FSM

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Message-ID: <1451527755.20140.6.camel@mtksdaap41>
Date:	Thu, 31 Dec 2015 10:09:15 +0800
From:	Henry Chen <henryc.chen@...iatek.com>
To:	Matthias Brugger <matthias.bgg@...il.com>
CC:	Sascha Hauer <s.hauer@...gutronix.de>,
	<linux-arm-kernel@...ts.infradead.org>,
	<linux-mediatek@...ts.infradead.org>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] soc: mediatek: PMIC wrap: Clear the vldclr if state
 machine is stay on FSM_VLDCLR state.

Hi Matthias,

On Wed, 2015-12-30 at 19:02 +0100, Matthias Brugger wrote:
> 
> On 22/12/15 08:51, Henry Chen wrote:
> > Sometimes PMIC is too busy to send data in time to cause pmic wrap timeout,
> > because pmic wrap is waiting for FSM_VLDCLR after finishing WACS2_CMD. It
> > just return error when issue happened, so the state machine will stay on
> > FSM_VLDCLR state when data send back later by PMIC and timeout again in next
> > time because pmic wrap waiting for FSM_IDLE state at the begining of the
> > read/write function.
> >
> > Clear the vldclr when timeout if state machine is stay on FSM_VLDCLR.
> >
> > Signed-off-by: Henry Chen <henryc.chen@...iatek.com>
> > ---
> >   drivers/soc/mediatek/mtk-pmic-wrap.c | 16 ++++++++++++++--
> >   1 file changed, 14 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/soc/mediatek/mtk-pmic-wrap.c b/drivers/soc/mediatek/mtk-pmic-wrap.c
> > index 105597a..ccd5337 100644
> > --- a/drivers/soc/mediatek/mtk-pmic-wrap.c
> > +++ b/drivers/soc/mediatek/mtk-pmic-wrap.c
> > @@ -443,10 +443,16 @@ static int pwrap_wait_for_state(struct pmic_wrapper *wrp,
> >   static int pwrap_write(struct pmic_wrapper *wrp, u32 adr, u32 wdata)
> >   {
> >   	int ret;
> > +	u32 val;
> >
> >   	ret = pwrap_wait_for_state(wrp, pwrap_is_fsm_idle);
> > -	if (ret)
> > +	if (ret) {
> > +		/* Clear vldclr bit if state is on the WACS_FSM_WFVLDCLR */
> > +		val = pwrap_readl(wrp, PWRAP_WACS2_RDATA);
> > +		if (PWRAP_GET_WACS_FSM(val) == PWRAP_WACS_FSM_WFVLDCLR)
> > +			pwrap_writel(wrp, 1, PWRAP_WACS2_VLDCLR);
> >   		return ret;
> > +	}
> 
> I would prefer to have this encapsulated in a (inline) function. Maybe 
> with better description then just the one line comment.
> 
> Thanks,
> Matthias

Ok, I will make the description more clear, do you means write the
function like below and used it on pwrap_write/pwrap_read.

static inline void pwrap_leave_fsm_vldclr(struct pmic_wrapper *wrp)
{
	if (pwrap_is_fsm_vldclr(wrp))
		pwrap_writel(wrp, 1, PWRAP_WACS2_VLDCLR);
}


Thanks,
Henry

> 
> >
> >   	pwrap_writel(wrp, (1 << 31) | ((adr >> 1) << 16) | wdata,
> >   			PWRAP_WACS2_CMD);
> > @@ -457,10 +463,16 @@ static int pwrap_write(struct pmic_wrapper *wrp, u32 adr, u32 wdata)
> >   static int pwrap_read(struct pmic_wrapper *wrp, u32 adr, u32 *rdata)
> >   {
> >   	int ret;
> > +	u32 val;
> >
> >   	ret = pwrap_wait_for_state(wrp, pwrap_is_fsm_idle);
> > -	if (ret)
> > +	if (ret) {
> > +		/* Clear vldclr bit if state is on the WACS_FSM_WFVLDCLR */
> > +		val = pwrap_readl(wrp, PWRAP_WACS2_RDATA);
> > +		if (PWRAP_GET_WACS_FSM(val) == PWRAP_WACS_FSM_WFVLDCLR)
> > +			pwrap_writel(wrp, 1, PWRAP_WACS2_VLDCLR);
> >   		return ret;
> > +	}
> >
> >   	pwrap_writel(wrp, (adr >> 1) << 16, PWRAP_WACS2_CMD);
> >
> >


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