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

From: Andre Prendel <[email-masked]>
Date: Tue, 18 May 2010 13:38:38 +0200

On Mon, May 17, 2010 at 04:30:24PM -0400, Jeff Angielski wrote:
> 
> Here is a second attempt at a patch to add nfactor support to the tmp421 driver.

Hi Jeff,

only a few minor issues, see below.
 
> This includes the changes as suggested by Andre Prendel, the original driver author.
> 
> 
> >From 8ebe84174ff6bd294656d77183758044f19d8900 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..ce1f6d1 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]);
> +		}

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?

>  		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)

Indentation of the arguments is wrong (see other functions).

> +{
> +	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)

ditto

> +{
> +	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));

ditto

> +	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);

And again three times.

>  
>  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
>  };

All the rest looks good.

Thanks,
Andre

> -- 
> Jeff Angielski
> The PTR Group
> www.theptrgroup.com
> 
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