linux-kernel - Re: [PATCH v2 3/4] i2c: imx: Simplify stopped state tracking

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Message-ID: <20180724075919.iyysd7dtbddvbavq@pengutronix.de>
Date:   Tue, 24 Jul 2018 09:59:19 +0200
From:   Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>
To:     Esben Haabendal <esben.haabendal@...il.com>
Cc:     linux-i2c@...r.kernel.org,
        Wolfram Sang <wsa+renesas@...g-engineering.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Yuan Yao <yao.yuan@...escale.com>,
        Esben Haabendal <eha@...f.com>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Phil Reid <preid@...ctromag.com.au>,
        Lucas Stach <l.stach@...gutronix.de>,
        Clemens Gruber <clemens.gruber@...ruber.com>,
        Peter Rosin <peda@...ntia.se>,
        Fabio Estevam <fabio.estevam@....com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 3/4] i2c: imx: Simplify stopped state tracking

On Mon, Jul 09, 2018 at 11:43:03AM +0200, Esben Haabendal wrote:
> From: Esben Haabendal <eha@...f.com>
> 
> Always update the stopped state when busy status have been checked.
> This is identical to what was done before, with the exception of error
> handling.
> Without this change, some errors cause the stopped state to be left in
> incorrect state in i2c_imx_stop(), i2c_imx_dma_read(), i2c_imx_read() and
> i2c_imx_xfer().
> 
> Signed-off-by: Esben Haabendal <eha@...f.com>
> ---
>  drivers/i2c/busses/i2c-imx.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
> index d86f152176a4..1db8e6790afc 100644
> --- a/drivers/i2c/busses/i2c-imx.c
> +++ b/drivers/i2c/busses/i2c-imx.c
> @@ -421,10 +421,14 @@ static int i2c_imx_bus_busy(struct imx_i2c_struct *i2c_imx, int for_busy)
>  			return -EAGAIN;
>  		}
>  
> -		if (for_busy && (temp & I2SR_IBB))
> +		if (for_busy && (temp & I2SR_IBB)) {
> +			i2c_imx->stopped = 0;
>  			break;
> -		if (!for_busy && !(temp & I2SR_IBB))
> +		}
> +		if (!for_busy && !(temp & I2SR_IBB)) {
> +			i2c_imx->stopped = 1;
>  			break;
> +		}

Would it make sense to assign to ->stopped independent of for_busy?

>  		if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) {
>  			dev_dbg(&i2c_imx->adapter.dev,
>  				"<%s> I2C bus is busy\n", __func__);
> @@ -538,7 +542,6 @@ static int i2c_imx_start(struct imx_i2c_struct *i2c_imx)
>  	result = i2c_imx_bus_busy(i2c_imx, 1);
>  	if (result)
>  		return result;
> -	i2c_imx->stopped = 0;
>  
>  	temp |= I2CR_IIEN | I2CR_MTX | I2CR_TXAK;
>  	temp &= ~I2CR_DMAEN;
> @@ -569,7 +572,6 @@ static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx)
>  
>  	if (!i2c_imx->stopped) {
>  		i2c_imx_bus_busy(i2c_imx, 0);
> -		i2c_imx->stopped = 1;
>  	}

The braces can go away here.
>  
>  	/* Disable I2C controller */

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |