Re: [PATCH 4/5] [media] winbond-cir: One variable and its check less in wbcir_shutdown() after error detection

[Sean Young]

On Fri, Oct 14, 2016 at 01:44:02PM +0200, SF Markus Elfring wrote:
> From: Markus Elfring <elfring@xxxxxxxxxxxxxxxxxxxxx>
> Date: Fri, 14 Oct 2016 12:48:41 +0200
> 
> The local variable "do_wake" was set to "false" after an invalid system
> setting was detected so that a bit of error handling was triggered.
> 
> * Replace these assignments by direct jumps to the source code with the
> desired exception handling.
> 
> * Delete this status variable and a corresponding check which became
>   unnecessary with this refactoring.
> 
> Signed-off-by: Markus Elfring <elfring@xxxxxxxxxxxxxxxxxxxxx>
> ---
>  drivers/media/rc/winbond-cir.c | 78 ++++++++++++++++++------------------------
>  1 file changed, 34 insertions(+), 44 deletions(-)
> 
> diff --git a/drivers/media/rc/winbond-cir.c b/drivers/media/rc/winbond-cir.c
> index 9d05e17..3d286b9 100644
> --- a/drivers/media/rc/winbond-cir.c
> +++ b/drivers/media/rc/winbond-cir.c
> @@ -699,16 +699,13 @@ wbcir_shutdown(struct pnp_dev *device)
>  {
>  	struct device *dev = &device->dev;
>  	struct wbcir_data *data = pnp_get_drvdata(device);
> -	bool do_wake = true;
>  	u8 match[11];
>  	u8 mask[11];
>  	u8 rc6_csl;
>  	int i;
>  
> -	if (wake_sc == INVALID_SCANCODE || !device_may_wakeup(dev)) {
> -		do_wake = false;
> -		goto finish;
> -	}
> +	if (wake_sc == INVALID_SCANCODE || !device_may_wakeup(dev))
> +		goto clear_bits;
>  
>  	rc6_csl = 0;
>  	memset(match, 0, sizeof(match));
> @@ -716,9 +713,8 @@ wbcir_shutdown(struct pnp_dev *device)
>  	switch (protocol) {
>  	case IR_PROTOCOL_RC5:
>  		if (wake_sc > 0xFFF) {
> -			do_wake = false;
>  			dev_err(dev, "RC5 - Invalid wake scancode\n");
> -			break;
> +			goto clear_bits;
>  		}
>  
>  		/* Mask = 13 bits, ex toggle */
> @@ -735,9 +731,8 @@ wbcir_shutdown(struct pnp_dev *device)
>  
>  	case IR_PROTOCOL_NEC:
>  		if (wake_sc > 0xFFFFFF) {
> -			do_wake = false;
>  			dev_err(dev, "NEC - Invalid wake scancode\n");
> -			break;
> +			goto clear_bits;
>  		}
>  
>  		mask[0] = mask[1] = mask[2] = mask[3] = 0xFF;
> @@ -757,9 +752,8 @@ wbcir_shutdown(struct pnp_dev *device)
>  
>  		if (wake_rc6mode == 0) {
>  			if (wake_sc > 0xFFFF) {
> -				do_wake = false;
>  				dev_err(dev, "RC6 - Invalid wake scancode\n");
> -				break;
> +				goto clear_bits;
>  			}
>  
>  			/* Command */
> @@ -813,9 +807,8 @@ wbcir_shutdown(struct pnp_dev *device)
>  			} else if (wake_sc <= 0x007FFFFF) {
>  				rc6_csl = 60;
>  			} else {
> -				do_wake = false;
>  				dev_err(dev, "RC6 - Invalid wake scancode\n");
> -				break;
> +				goto clear_bits;
>  			}
>  
>  			/* Header */
> @@ -825,49 +818,38 @@ wbcir_shutdown(struct pnp_dev *device)
>  			mask[i++] = 0x0F;
>  
>  		} else {
> -			do_wake = false;
>  			dev_err(dev, "RC6 - Invalid wake mode\n");
> +			goto clear_bits;
>  		}
>  
>  		break;
>  
>  	default:
> -		do_wake = false;
> -		break;
> +		goto clear_bits;
>  	}
>  
> -finish:
> -	if (do_wake) {
> -		/* Set compare and compare mask */
> -		wbcir_set_bits(data->wbase + WBCIR_REG_WCEIR_INDEX,
> -			       WBCIR_REGSEL_COMPARE | WBCIR_REG_ADDR0,
> -			       0x3F);
> -		outsb(data->wbase + WBCIR_REG_WCEIR_DATA, match, 11);
> -		wbcir_set_bits(data->wbase + WBCIR_REG_WCEIR_INDEX,
> -			       WBCIR_REGSEL_MASK | WBCIR_REG_ADDR0,
> -			       0x3F);
> -		outsb(data->wbase + WBCIR_REG_WCEIR_DATA, mask, 11);
> -
> -		/* RC6 Compare String Len */
> -		outb(rc6_csl, data->wbase + WBCIR_REG_WCEIR_CSL);
> -
> -		/* Clear status bits NEC_REP, BUFF, MSG_END, MATCH */
> -		wbcir_set_bits(data->wbase + WBCIR_REG_WCEIR_STS, 0x17, 0x17);
> +	/* Set compare and compare mask */
> +	wbcir_set_bits(data->wbase + WBCIR_REG_WCEIR_INDEX,
> +		       WBCIR_REGSEL_COMPARE | WBCIR_REG_ADDR0,
> +		       0x3F);
> +	outsb(data->wbase + WBCIR_REG_WCEIR_DATA, match, 11);
> +	wbcir_set_bits(data->wbase + WBCIR_REG_WCEIR_INDEX,
> +		       WBCIR_REGSEL_MASK | WBCIR_REG_ADDR0,
> +		       0x3F);
> +	outsb(data->wbase + WBCIR_REG_WCEIR_DATA, mask, 11);
>  
> -		/* Clear BUFF_EN, Clear END_EN, Set MATCH_EN */
> -		wbcir_set_bits(data->wbase + WBCIR_REG_WCEIR_EV_EN, 0x01, 0x07);
> +	/* RC6 Compare String Len */
> +	outb(rc6_csl, data->wbase + WBCIR_REG_WCEIR_CSL);
>  
> -		/* Set CEIR_EN */
> -		wbcir_set_bits(data->wbase + WBCIR_REG_WCEIR_CTL, 0x01, 0x01);
> -
> -	} else {
> -		/* Clear BUFF_EN, Clear END_EN, Clear MATCH_EN */
> -		wbcir_set_bits(data->wbase + WBCIR_REG_WCEIR_EV_EN, 0x00, 0x07);
> +	/* Clear status bits NEC_REP, BUFF, MSG_END, MATCH */
> +	wbcir_set_bits(data->wbase + WBCIR_REG_WCEIR_STS, 0x17, 0x17);
>  
> -		/* Clear CEIR_EN */
> -		wbcir_set_bits(data->wbase + WBCIR_REG_WCEIR_CTL, 0x00, 0x01);
> -	}
> +	/* Clear BUFF_EN, Clear END_EN, Set MATCH_EN */
> +	wbcir_set_bits(data->wbase + WBCIR_REG_WCEIR_EV_EN, 0x01, 0x07);
>  
> +	/* Set CEIR_EN */
> +	wbcir_set_bits(data->wbase + WBCIR_REG_WCEIR_CTL, 0x01, 0x01);
> +set_irqmask:
>  	/*
>  	 * ACPI will set the HW disable bit for SP3 which means that the
>  	 * output signals are left in an undefined state which may cause
> @@ -876,6 +858,14 @@ wbcir_shutdown(struct pnp_dev *device)
>  	 */
>  	wbcir_set_irqmask(data, WBCIR_IRQ_NONE);
>  	disable_irq(data->irq);
> +	return;
> +clear_bits:
> +	/* Clear BUFF_EN, Clear END_EN, Clear MATCH_EN */
> +	wbcir_set_bits(data->wbase + WBCIR_REG_WCEIR_EV_EN, 0x00, 0x07);
> +
> +	/* Clear CEIR_EN */
> +	wbcir_set_bits(data->wbase + WBCIR_REG_WCEIR_CTL, 0x00, 0x01);
> +	goto set_irqmask;

I'm not convinced that adding a goto which goes backwards is making this
code any more readible, just so that a local variable can be dropped.


Sean

>  }
>  
>  static int
> -- 
> 2.10.1
> 
> --
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