On Tue, Jul 20, 2010 at 11:09:53AM -0400, Andre Prendel wrote:
> On Thu, May 20, 2010 at 09:35:56PM +0200, Andre Prendel wrote:
> > On Thu, May 20, 2010 at 03:07:05PM -0400, Jeff Angielski wrote:
> > > In any event, here it is again:
> >
> > Acked-by: Andre Prendel <andre.prendel@xxxxxx>
>
> Hi Jeff,
>
> I'de suggest to resend the patch with my acked-by to the lm-sensors list and
> Andrew Morton. It looks like Jean is too busy at the moment.
>
> Regards,
> Andre
>
> > > >From 9acd29ff48c64e58a7f5cdb888c86e737c56281c Mon Sep 17 00:00:00 2001
> > > From: Jeff Angielski <jeff@xxxxxxxxxxxxxxx>
> > > Date: Mon, 10 May 2010 10:26:34 -0400
> > > Subject: [PATCH] hwmon: (tmp421) Add nfactor support
> > >
> > > Add support for reading and writing the n-factor correction
> > > registers. This is needed to compensate for the characteristics
> > > of a particular sensor hanging off of the remote channels.
> > >
My concerns with this approach are
1) It changes the sysfs abi. libsensors won't support it. It opens up
a can of worms with everyone starting to put chip-specific extensions
into the ABI. If such an extension has to be made, it should be a) really necessary
and b) a generic extension which applies to all chips.
2) My understanding is that value adjustments are supposed to be made via sensors.conf,
and that values reported by the chip should always be 'raw', ie unadjusted
values.
Instead of exporting n_adjust to the user via sysfs, it might make more sense
to reset the correction factor to its default (if it was changed), and handle
required adjustments in sensors.conf.
Even if Jean doesn't have time to handle the patch, you should at least get his Ack
for the ABI changes.
Guenter
> > >
> > > Signed-off-by: Jeff Angielski <jeff@xxxxxxxxxxxxxxx>
> > > ---
> > > Documentation/hwmon/tmp421 | 19 +++++++++++++++++++
> > > drivers/hwmon/tmp421.c | 41 +++++++++++++++++++++++++++++++++++++++++
> > > 2 files changed, 60 insertions(+), 0 deletions(-)
> > >
> > > diff --git a/Documentation/hwmon/tmp421 b/Documentation/hwmon/tmp421
> > > index 0cf07f8..668228a 100644
> > > --- a/Documentation/hwmon/tmp421
> > > +++ b/Documentation/hwmon/tmp421
> > > @@ -17,6 +17,7 @@ Supported chips:
> > >
> > > Authors:
> > > Andre Prendel <andre.prendel@xxxxxx>
> > > + Jeff Angielski <jeff@xxxxxxxxxxxxxxx>
> > >
> > > Description
> > > -----------
> > > @@ -34,3 +35,21 @@ the temperature values via the following sysfs files:
> > >
> > > temp[1-4]_input
> > > temp[2-4]_fault
> > > +
> > > +The chips allow the user to adjust the n-factor value that is used
> > > +when converting the remote channel measurements to temperature. The
> > > +adjustment has a range of -128 to +127 that yields an effective
> > > +n-factor range of 0.706542 to 1.747977. The power on reset value
> > > +for the adjustment is 0 which results in an n-factor of 1.008.
> > > +
> > > +The effective n-factor is calculated according to the following
> > > +equation:
> > > +
> > > +n_factor = (1.008 * 300) / (300 - nfactor_adjust)
> > > +
> > > +The driver exports the n-factor adjustment value via the following
> > > +sysfs files:
> > > +
> > > +temp[2-4]_n_adjust
> > > +
> > > +
> > > diff --git a/drivers/hwmon/tmp421.c b/drivers/hwmon/tmp421.c
> > > index 738c472..dfd62be 100644
> > > --- a/drivers/hwmon/tmp421.c
> > > +++ b/drivers/hwmon/tmp421.c
> > > @@ -49,6 +49,7 @@ enum chips { tmp421, tmp422, tmp423 };
> > >
> > > static const u8 TMP421_TEMP_MSB[4] = { 0x00, 0x01, 0x02, 0x03 };
> > > static const u8 TMP421_TEMP_LSB[4] = { 0x10, 0x11, 0x12, 0x13 };
> > > +static const u8 TMP421_N_CORRECT[3] = { 0x21, 0x22, 0x23 };
> > >
> > > /* Flags */
> > > #define TMP421_CONFIG_SHUTDOWN 0x40
> > > @@ -76,6 +77,7 @@ struct tmp421_data {
> > > int channels;
> > > u8 config;
> > > s16 temp[4];
> > > + s8 n_adjust[3];
> > > };
> > >
> > > static int temp_from_s16(s16 reg)
> > > @@ -115,6 +117,10 @@ static struct tmp421_data *tmp421_update_device(struct device *dev)
> > > data->temp[i] |= i2c_smbus_read_byte_data(client,
> > > TMP421_TEMP_LSB[i]);
> > > }
> > > + for (i = 1; i < data->channels; i++) {
> > > + data->n_adjust[i - 1] = i2c_smbus_read_byte_data(client,
> > > + TMP421_N_CORRECT[i - 1]);
> > > + }
> > > data->last_updated = jiffies;
> > > data->valid = 1;
> > > }
> > > @@ -157,6 +163,32 @@ static ssize_t show_fault(struct device *dev,
> > > return sprintf(buf, "0\n");
> > > }
> > >
> > > +static ssize_t show_n_adjust(struct device *dev,
> > > + struct device_attribute *devattr, char *buf)
> > > +{
> > > + int index = to_sensor_dev_attr(devattr)->index;
> > > + struct tmp421_data *data = tmp421_update_device(dev);
> > > +
> > > + return sprintf(buf, "%d\n", data->n_adjust[index - 1]);
> > > +}
> > > +
> > > +static ssize_t set_n_adjust(struct device *dev,
> > > + struct device_attribute *devattr,
> > > + const char *buf, size_t count)
> > > +{
> > > + struct i2c_client *client = to_i2c_client(dev);
> > > + struct tmp421_data *data = i2c_get_clientdata(client);
> > > + int index = to_sensor_dev_attr(devattr)->index;
> > > + int n_adjust = simple_strtol(buf, NULL, 10);
> > > +
> > > + mutex_lock(&data->update_lock);
> > > + i2c_smbus_write_byte_data(client, TMP421_N_CORRECT[index - 1],
> > > + SENSORS_LIMIT(n_adjust, -128, 127));
> > > + mutex_unlock(&data->update_lock);
> > > +
> > > + return count;
> > > +}
> > > +
> > > static mode_t tmp421_is_visible(struct kobject *kobj, struct attribute *a,
> > > int n)
> > > {
> > > @@ -177,19 +209,28 @@ static mode_t tmp421_is_visible(struct kobject *kobj, struct attribute *a,
> > > static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_value, NULL, 0);
> > > static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp_value, NULL, 1);
> > > static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_fault, NULL, 1);
> > > +static SENSOR_DEVICE_ATTR(temp2_n_adjust, S_IRUSR | S_IWUSR | S_IRGRP,
> > > + show_n_adjust, set_n_adjust, 1);
> > > static SENSOR_DEVICE_ATTR(temp3_input, S_IRUGO, show_temp_value, NULL, 2);
> > > static SENSOR_DEVICE_ATTR(temp3_fault, S_IRUGO, show_fault, NULL, 2);
> > > +static SENSOR_DEVICE_ATTR(temp3_n_adjust, S_IRUSR | S_IWUSR | S_IRGRP,
> > > + show_n_adjust, set_n_adjust, 2);
> > > static SENSOR_DEVICE_ATTR(temp4_input, S_IRUGO, show_temp_value, NULL, 3);
> > > static SENSOR_DEVICE_ATTR(temp4_fault, S_IRUGO, show_fault, NULL, 3);
> > > +static SENSOR_DEVICE_ATTR(temp4_n_adjust, S_IRUSR | S_IWUSR | S_IRGRP,
> > > + show_n_adjust, set_n_adjust, 3);
> > >
> > > static struct attribute *tmp421_attr[] = {
> > > &sensor_dev_attr_temp1_input.dev_attr.attr,
> > > &sensor_dev_attr_temp2_input.dev_attr.attr,
> > > &sensor_dev_attr_temp2_fault.dev_attr.attr,
> > > + &sensor_dev_attr_temp2_n_adjust.dev_attr.attr,
> > > &sensor_dev_attr_temp3_input.dev_attr.attr,
> > > &sensor_dev_attr_temp3_fault.dev_attr.attr,
> > > + &sensor_dev_attr_temp3_n_adjust.dev_attr.attr,
> > > &sensor_dev_attr_temp4_input.dev_attr.attr,
> > > &sensor_dev_attr_temp4_fault.dev_attr.attr,
> > > + &sensor_dev_attr_temp4_n_adjust.dev_attr.attr,
> > > NULL
> > > };
> > >
> > > --
> > > 1.7.0.4
> > >
> > >
> > > --
> > > Jeff Angielski
> > > The PTR Group
> > > www.theptrgroup.com
> > >
> > > _______________________________________________
> > > lm-sensors mailing list
> > > lm-sensors@xxxxxxxxxxxxxx
> > > http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
> >
> > _______________________________________________
> > lm-sensors mailing list
> > lm-sensors@xxxxxxxxxxxxxx
> > http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
>
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