linux-kernel - Re: [RESEND PATCH v2] soc: mediatek: PMIC wrap: Clear the vldclr if state machine stay on FSM

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Message-ID: <568F8AB2.6080503@gmail.com>
Date:	Fri, 8 Jan 2016 11:08:50 +0100
From:	Matthias Brugger <matthias.bgg@...il.com>
To:	Ricky Liang <jcliang@...omium.org>,
	Henry Chen <henryc.chen@...iatek.com>
Cc:	Sascha Hauer <s.hauer@...gutronix.de>,
	"moderated list:ARM/Mediatek SoC..." 
	<linux-arm-kernel@...ts.infradead.org>,
	"moderated list:ARM/Mediatek SoC..." 
	<linux-mediatek@...ts.infradead.org>,
	open list <linux-kernel@...r.kernel.org>
Subject: Re: [RESEND PATCH v2] soc: mediatek: PMIC wrap: Clear the vldclr if
 state machine stay on FSM_VLDCLR state.



On 08/01/16 03:43, Ricky Liang wrote:
> On Mon, Jan 4, 2016 at 8:02 PM, Henry Chen <henryc.chen@...iatek.com> 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 beginning of the
>> read/write function.
>>
>> Clear the vldclr when timeout if state machine stay on FSM_VLDCLR.
>>
>> Signed-off-by: Henry Chen <henryc.chen@...iatek.com>
>> ---
>> Changes since v1:
>> Encapsulated the code in a inline function, and add a descriptive comment.
>> ---
>>   drivers/soc/mediatek/mtk-pmic-wrap.c | 30 ++++++++++++++++++++++++++++--
>>   1 file changed, 28 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/soc/mediatek/mtk-pmic-wrap.c b/drivers/soc/mediatek/mtk-pmic-wrap.c
>> index 105597a..af919b1 100644
>> --- a/drivers/soc/mediatek/mtk-pmic-wrap.c
>> +++ b/drivers/soc/mediatek/mtk-pmic-wrap.c
>> @@ -412,6 +412,12 @@ static bool pwrap_is_fsm_vldclr(struct pmic_wrapper *wrp)
>>          return PWRAP_GET_WACS_FSM(val) == PWRAP_WACS_FSM_WFVLDCLR;
>>   }
>>
>> +static inline void pwrap_leave_fsm_vldclr(struct pmic_wrapper *wrp)
>> +{
>> +       if (pwrap_is_fsm_vldclr(wrp))
>> +               pwrap_writel(wrp, 1, PWRAP_WACS2_VLDCLR);
>> +}
>> +
>>   static bool pwrap_is_sync_idle(struct pmic_wrapper *wrp)
>>   {
>>          return pwrap_readl(wrp, PWRAP_WACS2_RDATA) & PWRAP_STATE_SYNC_IDLE0;
>> @@ -445,8 +451,18 @@ static int pwrap_write(struct pmic_wrapper *wrp, u32 adr, u32 wdata)
>>          int ret;
>>
>>          ret = pwrap_wait_for_state(wrp, pwrap_is_fsm_idle);
>> -       if (ret)
>> +       if (ret) {
>> +               /*
>> +                * Timeout issue sometimes caused by the last read command
>> +                * failed because pmic wrap could not got the FSM_VLDCLR
>> +                * in time after finishing WACS2_CMD. It made state machine
>> +                * still on FSM_VLDCLR and timeout next time.
>> +                * Check the status of FSM and clear the vldclr to recovery the
>> +                * error.
>> +                */
>> +               pwrap_leave_fsm_vldclr(wrp);
>>                  return ret;
>> +       }
>>
>>          pwrap_writel(wrp, (1 << 31) | ((adr >> 1) << 16) | wdata,
>>                          PWRAP_WACS2_CMD);
>> @@ -459,8 +475,18 @@ static int pwrap_read(struct pmic_wrapper *wrp, u32 adr, u32 *rdata)
>>          int ret;
>>
>>          ret = pwrap_wait_for_state(wrp, pwrap_is_fsm_idle);
>> -       if (ret)
>> +       if (ret) {
>> +               /*
>> +                * Timeout issue sometimes caused by the last read command
>> +                * failed because pmic wrap could not got the FSM_VLDCLR
>> +                * in time after finishing WACS2_CMD. It made state machine
>> +                * still on FSM_VLDCLR and timeout next time.
>> +                * Check the status of FSM and clear the vldclr to recovery the
>> +                * error.
>> +                */
>> +               pwrap_leave_fsm_vldclr(wrp);
>>                  return ret;
>> +       }
>>
>>          pwrap_writel(wrp, (adr >> 1) << 16, PWRAP_WACS2_CMD);
>>
>> --
>> 1.9.1
>>
>> --
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>
>
> Tested-by: Ricky Liang <jcliang@...omium.org>
>
> On our test platform this patch fixes PMIC communication erros.
>

I put the comment above the function declaration.

Applied to v4.5-next/soc

Thanks.