Subject: Re: [lm-sensors] [PATCH] hwmon: (tmp421) Add nfactor support (2nd attempt)

From: Andre Prendel <[email-masked]>
Date: Wed, 19 May 2010 09:26:59 +0200

On Tue, May 18, 2010 at 10:35:21AM -0400, Jeff Angielski wrote:
> On 05/18/2010 07:38 AM, Andre Prendel wrote:
> 
> > I'd prefer starting i with 0 and as condition i < data->channels - 1.
> > 
> > for (i = 0; i < data->channels -1; i++) {
> > 	data->nfactor[i] = i2c_smbus_read_byte_data(client,
> > 		TMP421_NFACTOR[i]);
> > }
> > 
> > What do you think?
> 
> The first channel is the local channel which does not support nfactor,
> so we skip it.  Having the for loop start at 1 illustrates this concept.
> 
> > Indentation of the arguments is wrong (see other functions).
> 
> Should be fixed in the patch below.  

Ok, so there is only one remaining task :) Please update the documentation under
Documentation/hwmon/tmp421. Then you will get my Acked-by.

Jean, should we describe this interface in Documentation/hwmon/sysfs-interface
too? For the moment tmp421 is the only driver implementing it. 
 
> I am not sure why the patch file itself still shows the function arguments 
> off by one.  When I apply it to a raw tmp421.c all of the arguments 
> line up correctly.
> 
> After rebasing the changes, I am creating the patch as:
> 
> $ git format-patch -1 HEAD
> 
> Pretty simple stuff...
> 
> 
> 
> >From 467c74e1d8118e34e84a150f18b5e55c6593c777 Mon Sep 17 00:00:00 2001
> From: Jeff Angielski <[email-masked]>
> 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.
> 
> Signed-off-by: Jeff Angielski <[email-masked]>
> ---
>  drivers/hwmon/tmp421.c |   41 +++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 41 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/hwmon/tmp421.c b/drivers/hwmon/tmp421.c
> index 738c472..7944627 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_NFACTOR[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 nfactor[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->nfactor[i - 1] = i2c_smbus_read_byte_data(client,
> +				TMP421_NFACTOR[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_nfactor(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->nfactor[index - 1]);
> +}
> +
> +static ssize_t set_nfactor(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 nfactor = simple_strtol(buf, NULL, 10);
> +
> +	mutex_lock(&data->update_lock);
> +	i2c_smbus_write_byte_data(client, TMP421_NFACTOR[index - 1],
> +				  SENSORS_LIMIT(nfactor, -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_nfactor, S_IRUSR | S_IWUSR | S_IRGRP,
> +			  show_nfactor, set_nfactor, 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_nfactor, S_IRUSR | S_IWUSR | S_IRGRP,
> +			  show_nfactor, set_nfactor, 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_nfactor, S_IRUSR | S_IWUSR | S_IRGRP,
> +			  show_nfactor, set_nfactor, 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_nfactor.dev_attr.attr,
>  	&sensor_dev_attr_temp3_input.dev_attr.attr,
>  	&sensor_dev_attr_temp3_fault.dev_attr.attr,
> +	&sensor_dev_attr_temp3_nfactor.dev_attr.attr,
>  	&sensor_dev_attr_temp4_input.dev_attr.attr,
>  	&sensor_dev_attr_temp4_fault.dev_attr.attr,
> +	&sensor_dev_attr_temp4_nfactor.dev_attr.attr,
>  	NULL
>  };
>
Thanks,
Andre