Re: [lm-sensors] PATCH: hwmon-fschmd-new-driver.patch

[Hans de Goede <j.w.r.degoede@hhs.nl>]

Jean Delvare wrote:
> Hi Hans,
> 
> On Fri, 21 Sep 2007 16:37:08 +0200, Hans de Goede wrote:
>> This patch adds a new merged driver for FSC sensor chips, it merges the fscher
>> and fscpos drivers and adds support for the FSC Scylla, Heracles and Heimdall
>> chips.
>>
>> This version of the driver has the following changes compared to the last
>> version posted to the lm-sensors list:
>> -bitmasks used changed from 0x0X to defines for better readability
>> -fan#_fault fault entries were added, these signal wether or not a fan is
>>   detected on the tachometer of fan#.
>>
>> Signed-off-by: Hans de Goede <j.w.r.degoede@hhs.nl>
>>
>> Reviews much appreciated!
> 
> Here you go.
> 

Thanks! I agree with most comments and will address them with a new version 
asap. I have questions about a few of them, see below.
Further more I've been thinking about replacing:

		/* Poseidon doesn't have TEMP_LIMIT registers */
		if (kind = fscpos && (i % 4) = 1)
			continue;

with (pseudo code for now):
		/* Poseidon doesn't have TEMP_LIMIT registers */
		if (kind = fscpos &&
			sscanf(fschmd_temp_attr[i].dev_attr.attr.name,
				"temp%d_ma%c", &dummy, &dummy) = 2)
			continue;

In this context:
	for (i = 0; i < (FSCHMD_NO_TEMP_SENSORS[data->kind] * 4); i++) {
		/* Poseidon doesn't have TEMP_LIMIT registers */
		if (kind = fscpos && (i % 4) = 1)
			continue;
		
		err = device_create_file(&new_client->dev,
					&fschmd_temp_attr[i].dev_attr);
		if (err)
			goto exit_remove_files;
	}

With the idea that the replacement code is better readable, and is (somewhat) 
resistent against adding attributes to the array. I'm not sure though, is this 
a change for the better or does it make things worse?

On to the questions about your comments:

>> +config SENSORS_FSCHMD
>> +	tristate "FSC Poseidon, Hermes, Scylla, Heracles and Heimdall"
> 
> In chronological order, Scylla would come before Hermes, and Heracles
> would be last.

I will change that in the kconfig, but I'll keep the current order in the driver.

>> + *  Scylla, Heracles and Heimdall chips
>> + *
>> + *  Based on the original 2.4 fscscy, 2.6 fscpos, 2.6 fscher and 2.6
>> + *  (candidate) fschmd drivers:
>> + *  Copyright (C) 2006 Thilo Cestonaro <thilo.cestonaro.external@fujitsu-siemens.com>
> 
> Line longer than 80 columns.
> 

Suggestions for breaking it up, without things becoming ugly? I think since 
this is just a comment its best left as is.

>> +/*
>> + * Sysfs attr show / store functions
>> + */
>> +
>> +static ssize_t show_in_value(struct device *dev,
>> +	struct device_attribute *devattr, char *buf)
>> +{
>> +	const int max_reading[3] = { 14200, 6600, 3300 };
> 
> Could be static.
> 

With what advantage? Its const so it goes to the code segment, so no stack 
usage, or am I missing something here?

>> +	struct fschmd_data *data;
>> +	u8 revision;
>> +	const char *names[5] = { "Scylla", "Poseidon", "Hermes", "Heracles",
>> +			"Heimdall" };
> 
> Could be static.
> 

Or constify the pointers with the same result as above? Which one is prefered?

>> +	strlcpy(new_client->name, FSCHMD_NAME, I2C_NAME_SIZE);
> 
> No! The _client_ name goes there, not the driver name. You want the
> Poseidon to appear as "fscpos", etc.
> 

AFAIK this determines what gets put in the name sysfs attribute, do I have this 
correct? I'm asking because in that case putting in fscpos, fscher or fscscy is 
not an option as libsensors and sensors 2.x have certain expectations about the 
old driver, they expect various non Documentation/hwmon/sysfs-interface 
compliant attributes to be there. If I'm mistaken and this is not what gets put 
in the name sysfs attr, then I'll modify it, otherwise we need another 
solution, maybe something not pretty like fscpos-new, fscher-new, etc.
>> +MODULE_AUTHOR("Hans de Goede <j.w.r.degoede@hhs.nl>");
>> +MODULE_DESCRIPTION("FSC Poseidon, Hermes, Scylla, Heracles and Heimdall driver");
>> +MODULE_LICENSE("GPL");
> 
> MODULE_DESCRIPTION Line longer that 80 characters.
> 

I don't know how stringent the guidelines are when it comes to the 80 chars 
limit, but to me breaking the MODULE_DESCRIPTION line up doesn't improve the 
readability.

Regards,

Hans

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