linux-kernel - Re: [PATCH] i2c: pxa: move to generic GPIO recovery

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Message-ID: <20201003185404.GH1551@shell.armlinux.org.uk>
Date:   Sat, 3 Oct 2020 19:54:04 +0100
From:   Russell King - ARM Linux admin <linux@...linux.org.uk>
To:     Codrin Ciubotariu <codrin.ciubotariu@...rochip.com>
Cc:     linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, wsa@...nel.org,
        alpawi@...zon.com
Subject: Re: [PATCH] i2c: pxa: move to generic GPIO recovery

On Sat, Oct 03, 2020 at 07:21:41PM +0300, Codrin Ciubotariu wrote:
> Starting with
> commit 75820314de26 ("i2c: core: add generic I2C GPIO recovery")
> GPIO bus recovery is supported by the I2C core, so we can remove the
> driver implementation and use that one instead.
> 
> Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@...rochip.com>
> ---
> 
> This patch is not tested.
> The only different thing should be the fact that the pinctl state is
> now switched back to the default state after the bus is enabled.
> 
>  drivers/i2c/busses/i2c-pxa.c | 75 +++---------------------------------
>  1 file changed, 6 insertions(+), 69 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
> index 35ca2c02c9b9..dd357b6e6c61 100644
> --- a/drivers/i2c/busses/i2c-pxa.c
> +++ b/drivers/i2c/busses/i2c-pxa.c
> @@ -264,9 +264,6 @@ struct pxa_i2c {
>  	u32			hs_mask;
>  
>  	struct i2c_bus_recovery_info recovery;
> -	struct pinctrl		*pinctrl;
> -	struct pinctrl_state	*pinctrl_default;
> -	struct pinctrl_state	*pinctrl_recovery;
>  };
>  
>  #define _IBMR(i2c)	((i2c)->reg_ibmr)
> @@ -1305,8 +1302,6 @@ static void i2c_pxa_prepare_recovery(struct i2c_adapter *adap)
>  	 */
>  	gpiod_set_value(i2c->recovery.scl_gpiod, ibmr & IBMR_SCLS);
>  	gpiod_set_value(i2c->recovery.sda_gpiod, ibmr & IBMR_SDAS);
> -
> -	WARN_ON(pinctrl_select_state(i2c->pinctrl, i2c->pinctrl_recovery));
>  }
>  
>  static void i2c_pxa_unprepare_recovery(struct i2c_adapter *adap)
> @@ -1325,8 +1320,6 @@ static void i2c_pxa_unprepare_recovery(struct i2c_adapter *adap)
>  		i2c_pxa_do_reset(i2c);
>  	}
>  
> -	WARN_ON(pinctrl_select_state(i2c->pinctrl, i2c->pinctrl_default));
> -

This won't fly. We need to put the pinctrl back into i2c mode _before_
we re-enable the I2C module, otherwise the I2C block will see logic 0
on both SCL and SDA which could confuse the block.

-- 
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