linux-kernel - Re: [PATCH 09/17] i2c: omap: ack IRQ in parts

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Message-ID: <20120614112017.GC31187@n2100.arm.linux.org.uk>
Date:	Thu, 14 Jun 2012 12:20:17 +0100
From:	Russell King - ARM Linux <linux@....linux.org.uk>
To:	Felipe Balbi <balbi@...com>
Cc:	ben-linux@...ff.org, Tony Lindgren <tony@...mide.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	w.sang@...gutronix.de, linux-i2c@...r.kernel.org,
	Linux OMAP Mailing List <linux-omap@...r.kernel.org>,
	Linux ARM Kernel Mailing List 
	<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH 09/17] i2c: omap: ack IRQ in parts

On Thu, Jun 14, 2012 at 01:20:42PM +0300, Felipe Balbi wrote:
> According to flow diagrams on OMAP TRMs,
> we should ACK the IRQ as they happen.

You don't explain that you're adding a new dev_err() statement into the
driver for a missing acknowledge.

What if you're probing for a device - can this cause spam to the kernel
console?  What if you have protocol mangling enabled with the "ignore
lack of ack bit set" ?

> 
> Signed-off-by: Felipe Balbi <balbi@...com>
> ---
>  drivers/i2c/busses/i2c-omap.c |   29 +++++++++++++++++------------
>  1 file changed, 17 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
> index f978b14..c00ba7d 100644
> --- a/drivers/i2c/busses/i2c-omap.c
> +++ b/drivers/i2c/busses/i2c-omap.c
> @@ -894,21 +894,20 @@ omap_i2c_isr(int this_irq, void *dev_id)
>  		}
>  
>  complete:
> -		/*
> -		 * Ack the stat in one go, but [R/X]DR and [R/X]RDY should be
> -		 * acked after the data operation is complete.
> -		 * Ref: TRM SWPU114Q Figure 18-31
> -		 */
> -		omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, stat &
> -				~(OMAP_I2C_STAT_RRDY | OMAP_I2C_STAT_RDR |
> -				OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR));
> -
> -		if (stat & OMAP_I2C_STAT_NACK)
> +		if (stat & OMAP_I2C_STAT_NACK) {
> +			dev_err(dev->dev, "No Acknowledge\n");
>  			err |= OMAP_I2C_STAT_NACK;
> +			omap_i2c_ack_stat(dev, OMAP_I2C_STAT_NACK);
> +			omap_i2c_complete_cmd(dev, err);
> +			return IRQ_HANDLED;
> +		}
>  
>  		if (stat & OMAP_I2C_STAT_AL) {
>  			dev_err(dev->dev, "Arbitration lost\n");
>  			err |= OMAP_I2C_STAT_AL;
> +			omap_i2c_ack_stat(dev, OMAP_I2C_STAT_NACK);
> +			omap_i2c_complete_cmd(dev, err);
> +			return IRQ_HANDLED;
>  		}
>  
>  		/*
> @@ -989,12 +988,18 @@ complete:
>  
>  		if (stat & OMAP_I2C_STAT_ROVR) {
>  			dev_err(dev->dev, "Receive overrun\n");
> -			dev->cmd_err |= OMAP_I2C_STAT_ROVR;
> +			err |= OMAP_I2C_STAT_ROVR;
> +			omap_i2c_ack_stat(dev, OMAP_I2C_STAT_ROVR);
> +			omap_i2c_complete_cmd(dev, err);
> +			return IRQ_HANDLED;
>  		}
>  
>  		if (stat & OMAP_I2C_STAT_XUDF) {
>  			dev_err(dev->dev, "Transmit underflow\n");
> -			dev->cmd_err |= OMAP_I2C_STAT_XUDF;
> +			err |= OMAP_I2C_STAT_XUDF;
> +			omap_i2c_ack_stat(dev, OMAP_I2C_STAT_XUDF);
> +			omap_i2c_complete_cmd(dev, err);
> +			return IRQ_HANDLED;
>  		}
>  	} while (stat);
>  
> -- 
> 1.7.10.4
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
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