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Message-ID: <20100913203206.GA2601@ericsson.com>
Date: Mon, 13 Sep 2010 13:32:06 -0700
From: Guenter Roeck <guenter.roeck@...csson.com>
To: Jean Delvare <khali@...ux-fr.org>
CC: Andrew Morton <akpm@...ux-foundation.org>,
"lm-sensors@...sensors.org" <lm-sensors@...sensors.org>,
"linux-doc@...r.kernel.org" <linux-doc@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 2/7] hwmon: (lm90) Introduce device feature bits
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@...csson.com>
> > ---
> > 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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