Re: [PATCH 3/4] watchdog: add driver for Ricoh RN5T618 watchdog

[Guenter Roeck <linux@roeck-us.net>]

On 08/28/2014 12:19 AM, Lee Jones wrote:
> On Wed, 27 Aug 2014, Guenter Roeck wrote:
>> On Wed, Aug 27, 2014 at 12:13:56AM +0200, Beniamino Galvani wrote:
>>> This adds a driver for the watchdog timer available in Ricoh RN5T618
>>> PMIC. The device supports a programmable expiration time of 1, 8, 32
>>> or 128 seconds.
>>>
>>> Signed-off-by: Beniamino Galvani <b.galvani@gmail.com>
>>> ---
>>>   drivers/watchdog/Kconfig       |   11 +++
>>>   drivers/watchdog/Makefile      |    1 +
>>>   drivers/watchdog/rn5t618_wdt.c |  196 ++++++++++++++++++++++++++++++++++++++++
>>>   include/linux/mfd/rn5t618.h    |    4 +
>>>   4 files changed, 212 insertions(+)
>>>   create mode 100644 drivers/watchdog/rn5t618_wdt.c
>
> [...]
>
>>> +++ b/drivers/watchdog/rn5t618_wdt.c
>>> @@ -0,0 +1,196 @@
>
> [...]
>
>>> +static int rn5t618_wdt_set_timeout(struct watchdog_device *wdt_dev,
>>> +				   unsigned int timeout)
>>> +{
>>> +	struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);
>>> +	int ret, i;
>>> +
>>> +	for (i = 0; i < ARRAY_SIZE(rn5t618_wdt_map); i++) {
>>> +		if (rn5t618_wdt_map[i].time + 1 >= timeout)
>>> +			break;
>>> +	}
>>> +
>>> +	if (i == ARRAY_SIZE(rn5t618_wdt_map))
>>> +		ret = -EINVAL;
>>
>> Can you simplify this a bit ? If you use
>>
>> 	if (i == ARRAY_SIZE(rn5t618_wdt_map))
>> 		return -EINVAL;
>
> This changes the semantics.
>
How so ? If ret is set to -EINVAL, the rest of the function won't do anything
but eventually return -EINVAL. I don't see why returning -EINVAL immediately
would change that.

Guenter

>>> +	else
>>
>> You can drop this else statement.
>>
>>> +		ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG,
>>> +					 RN5T618_WATCHDOG_WDOGTIM_M,
>>> +					 rn5t618_wdt_map[i].reg_val);
>>> +	if (!ret)
>>> +		wdt_dev->timeout = rn5t618_wdt_map[i].time;
>
> ... Isn't this important?
>
>>> +	return ret;
>>> +}
>