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

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Date:	Wed, 30 Dec 2015 19:02:41 +0100
From:	Matthias Brugger <matthias.bgg@...il.com>
To:	Henry Chen <henryc.chen@...iatek.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.



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

>
>   	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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