Re: [PATCH v2 2/7] hwmon: (lm90) Introduce device feature bits

[Guenter Roeck]

Hi Jean,

On Mon, Sep 13, 2010 at 03:30:30PM -0400, Jean Delvare wrote:
> On Thu, 9 Sep 2010 06:25:45 -0700, Guenter Roeck wrote:
> > Signed-off-by: Guenter Roeck <guenter.roeck@xxxxxxxxxxxx>
> > ---
> >  drivers/hwmon/lm90.c |   38 +++++++++++++++++++++++++-------------
> >  1 files changed, 25 insertions(+), 13 deletions(-)
> > 
> > diff --git a/drivers/hwmon/lm90.c b/drivers/hwmon/lm90.c
> > index aafed28..a81a053 100644
> > --- a/drivers/hwmon/lm90.c
> > +++ b/drivers/hwmon/lm90.c
> > @@ -142,7 +142,11 @@ enum chips { lm90, adm1032, lm99, lm86, max6657, adt7461, max6680, max6646,
> >  /*
> >   * Device flags
> >   */
> > -#define LM90_FLAG_ADT7461_EXT		0x01	/* ADT7461 extended mode */
> > +#define LM90_FLAG_ADT7461_EXT	0x01	/* ADT7461 extended mode	*/
> > +/* Device features */
> > +#define	LM90_HAVE_OFFSET	0x02	/* temperature offset register	*/
> > +#define	LM90_HAVE_LOCAL_EXT	0x04	/* extended local temperature	*/
> > +#define	LM90_HAVE_REM_LIMIT_EXT	0x08	/* extended remote limit	*/
> 
> Please always use a space, not a tab, between #define and the symbol
> name.
> 
Ok.

> When defining bit values, I suggest using the following notation:
> 
> #define LM90_HAVE_OFFSET	(1 << 2)	/* temperature offset register	*/
> #define LM90_HAVE_LOCAL_EXT	(1 << 3)	/* extended local temperature	*/
> 
> It is more immediately obvious that you have a bit vector.
> 
Makes sense. I often do, but didn't here for formatting reasons (getting close to 80 columns).
You'll see the impact in v3 of the patch.

> >  
> >  /*
> >   * Functions declaration
> > @@ -462,17 +466,16 @@ static ssize_t set_temp11(struct device *dev, struct device_attribute *devattr,
> >  	mutex_lock(&data->update_lock);
> >  	if (data->kind == adt7461)
> >  		data->temp11[nr] = temp_to_u16_adt7461(data, val);
> > -	else if (data->kind == max6657 || data->kind == max6680)
> > -		data->temp11[nr] = temp_to_s8(val) << 8;
> >  	else if (data->kind == max6646)
> >  		data->temp11[nr] = temp_to_u8(val) << 8;
> > +	else if (!(data->flags & LM90_HAVE_REM_LIMIT_EXT))
> 
> It would be more efficient to swap the last two statements to avoid the
> negation.
> 
Not sure about efficiency, but the code looks better that way. Done.

> > +		data->temp11[nr] = temp_to_s8(val) << 8;
> >  	else
> >  		data->temp11[nr] = temp_to_s16(val);
> >  
> >  	i2c_smbus_write_byte_data(client, reg[(nr - 1) * 2],
> >  				  data->temp11[nr] >> 8);
> > -	if (data->kind != max6657 && data->kind != max6680
> > -	    && data->kind != max6646)
> > +	if (data->flags & LM90_HAVE_REM_LIMIT_EXT)
> >  		i2c_smbus_write_byte_data(client, reg[(nr - 1) * 2 + 1],
> >  					  data->temp11[nr] & 0xff);
> >  	mutex_unlock(&data->update_lock);
> > @@ -847,6 +850,17 @@ static int lm90_probe(struct i2c_client *new_client,
> >  		break;
> >  	}
> >  
> > +	/* Set chip capabilities */
> > +	if (data->kind != max6657 && data->kind != max6646)
> > +		data->flags |= LM90_HAVE_OFFSET;
> > +
> > +	if (data->kind == max6657 || data->kind == max6646)
> > +		data->flags |= LM90_HAVE_LOCAL_EXT;
> > +
> > +	if (data->kind != max6657 && data->kind != max6646
> > +	    && data->kind != max6680)
> > +		data->flags |= LM90_HAVE_REM_LIMIT_EXT;
> > +
> >  	/* Initialize the LM90 chip */
> >  	lm90_init_client(new_client);
> >  
> > @@ -859,7 +873,7 @@ static int lm90_probe(struct i2c_client *new_client,
> >  		if (err)
> >  			goto exit_remove_files;
> >  	}
> > -	if (data->kind != max6657 && data->kind != max6646) {
> > +	if (data->flags & LM90_HAVE_OFFSET) {
> >  		err = device_create_file(&new_client->dev,
> >  					&sensor_dev_attr_temp2_offset.dev_attr);
> >  		if (err)
> > @@ -925,7 +939,7 @@ static int lm90_remove(struct i2c_client *client)
> >  	hwmon_device_unregister(data->hwmon_dev);
> >  	sysfs_remove_group(&client->dev.kobj, &lm90_group);
> >  	device_remove_file(&client->dev, &dev_attr_pec);
> > -	if (data->kind != max6657 && data->kind != max6646)
> > +	if (data->flags & LM90_HAVE_OFFSET)
> >  		device_remove_file(&client->dev,
> >  				   &sensor_dev_attr_temp2_offset.dev_attr);
> >  
> > @@ -1019,7 +1033,7 @@ static struct lm90_data *lm90_update_device(struct device *dev)
> >  		lm90_read_reg(client, LM90_REG_R_REMOTE_CRIT, &data->temp8[3]);
> >  		lm90_read_reg(client, LM90_REG_R_TCRIT_HYST, &data->temp_hyst);
> >  
> > -		if (data->kind == max6657 || data->kind == max6646) {
> > +		if (data->flags & LM90_HAVE_LOCAL_EXT) {
> >  			lm90_read16(client, LM90_REG_R_LOCAL_TEMP,
> >  				    MAX6657_REG_R_LOCAL_TEMPL,
> >  				    &data->temp11[4]);
> > @@ -1033,22 +1047,20 @@ static struct lm90_data *lm90_update_device(struct device *dev)
> >  
> >  		if (lm90_read_reg(client, LM90_REG_R_REMOTE_LOWH, &h) == 0) {
> >  			data->temp11[1] = h << 8;
> > -			if (data->kind != max6657 && data->kind != max6680
> > -			 && data->kind != max6646
> > +			if ((data->flags & LM90_HAVE_REM_LIMIT_EXT)
> >  			 && lm90_read_reg(client, LM90_REG_R_REMOTE_LOWL,
> >  					  &l) == 0)
> >  				data->temp11[1] |= l;
> >  		}
> >  		if (lm90_read_reg(client, LM90_REG_R_REMOTE_HIGHH, &h) == 0) {
> >  			data->temp11[2] = h << 8;
> > -			if (data->kind != max6657 && data->kind != max6680
> > -			 && data->kind != max6646
> > +			if ((data->flags & LM90_HAVE_REM_LIMIT_EXT)
> >  			 && lm90_read_reg(client, LM90_REG_R_REMOTE_HIGHL,
> >  					  &l) == 0)
> >  				data->temp11[2] |= l;
> >  		}
> >  
> > -		if (data->kind != max6657 && data->kind != max6646) {
> > +		if (data->flags & LM90_HAVE_OFFSET) {
> >  			if (lm90_read_reg(client, LM90_REG_R_REMOTE_OFFSH,
> >  					  &h) == 0
> >  			 && lm90_read_reg(client, LM90_REG_R_REMOTE_OFFSL,
> 
> Other than these minor implementation details, the changes look good, I
> like them.
> 
As always, excellent feedback. Thanks a lot!

Guenter
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