Subject: [PATCH v4 01/39] ARM: OMAP2+: gpmc: driver conversion

From: [email-masked] (Jon Hunter)
Date: Mon, 7 May 2012 11:02:58 -0500

Hi Afzal,

On 05/07/2012 06:01 AM, Mohammed, Afzal wrote:
> Hi Jon,
> 
> On Fri, May 04, 2012 at 21:57:10, Hunter, Jon wrote:
>>> -	gpmc_write_reg(GPMC_SYSCONFIG, l);
>>> -	gpmc_mem_init();
>>> +	switch (conf & GPMC_WAITPIN_MASK) {
>>> +	case GPMC_WAITPIN_0:
>>> +		idx =  GPMC_WAITPIN_IDX0;
>>> +		break;
>>> +	case GPMC_WAITPIN_1:
>>> +		idx =  GPMC_WAITPIN_IDX1;
>>> +		break;
>>> +	case GPMC_WAITPIN_2:
>>> +		idx =  GPMC_WAITPIN_IDX2;
>>> +		break;
>>> +	case GPMC_WAITPIN_3:
>>> +		idx =  GPMC_WAITPIN_IDX3;
>>> +		break;
>>> +	/* no waitpin */
>>> +	case 0:
>>> +		break;
>>> +	default:
>>> +		dev_err(gpmc->dev, "multiple waitpins selected on CS:%u\n", cs);
>>> +		return -EINVAL;
>>> +		break;
>>> +	}
>>
>> Why not combined case 0 and default? Both are invalid configurations so
>> just report invalid selection.
> 
> Case 0 is not invalid, a case where waitpin is not used, default refers
> to when a user selects multiple waitpins wrongly.

Ok. Then for case 0, just return here. If the polarity is set, you could
print an error here.

>>
>>>  
>>> -	/* initalize the irq_chained */
>>> -	irq = OMAP_GPMC_IRQ_BASE;
>>> -	for (cs = 0; cs < GPMC_CS_NUM; cs++) {
>>> -		irq_set_chip_and_handler(irq, &dummy_irq_chip,
>>> -						handle_simple_irq);
>>> -		set_irq_flags(irq, IRQF_VALID);
>>> -		irq++;
>>> +	switch (conf & GPMC_WAITPIN_POLARITY_MASK) {
>>> +	case GPMC_WAITPIN_ACTIVE_LOW:
>>> +		polarity = LOW;
>>> +		break;
>>> +	case GPMC_WAITPIN_ACTIVE_HIGH:
>>> +		polarity = HIGH;
>>> +		break;
>>> +	/* no waitpin */
>>> +	case 0:
>>> +		break;
>>> +	default:
>>> +		dev_err(gpmc->dev, "waitpin polarity set to low & high\n");
>>> +		return -EINVAL;
>>> +		break;
>>>  	}
>>
>> Again, combine case 0 and default as these are invalid.
> 
> Similar to above

If you return above, then case 0 is not needed.

>>
>>> +		if (gd->have_waitpin) {
>>> +			if (gd->waitpin != idx ||
>>> +					gd->waitpin_polarity != polarity) {
>>> +				dev_err(gpmc->dev, "error: conflict: waitpin %u with polarity %d on device %s.%d\n",
>>> +					gd->waitpin, gd->waitpin_polarity,
>>> +					gd->name, gd->id);
>>> +				return -EBUSY;
>>> +			}
>>> +		} else {
>>
>> Don't need the else as you are going to return in the above.
> 
> Not always, only in case of error

Ok, but seems that it can be simplified a little.

What happens if a device uses more than one wait-pin? In other words a
device with two chip-selects that uses two wait-pins?

>>
>>> +			gd->have_waitpin = true;
>>> +			gd->waitpin = idx;
>>> +			gd->waitpin_polarity = polarity;
>>> +		}
>>> +
>>> +		l &= ~GPMC_CONFIG1_WAIT_PIN_SEL_MASK;
>>> +		l |= GPMC_CONFIG1_WAIT_PIN_SEL(idx);
>>> +		gpmc_cs_write_reg(cs, GPMC_CS_CONFIG1, l);
>>> +	} else if (polarity) {
>>> +		dev_err(gpmc->dev, "error: waitpin polarity specified with out wait pin number on device %s.%d\n",
>>> +							gd->name, gd->id);
>>> +		return -EINVAL;
>>
>> Drop this else-if. The above switch statements will report the bad
>> configuration. This seems a bit redundant.
> 
> This is required as switch statements will not report error if polarity
> is specified, w/o waitpin to be used.

Ok, may be you can print that above when you detect that there are no
wait-pins selected.

Jon