Re: [PATCH v1] hwmon: migrate i8k procfs interface to sysfs

[Guenter Roeck <linux@roeck-us.net>]

On Wed, Oct 22, 2025 at 08:45:18PM +0200, Pali Rohár wrote:
> Sorry, but I do not understand this patch. dell-smm-hwmon driver is
> already using the sysfs interface provided by hwmon subsystem.
> 
It is also weirdly incomplete, and it claims to be "confidential and
intended for the named recipient(s) only". Git says it is corrupted,
and it doesn't look like a real patch.

> > --- a/drivers/hwmon/dell-smm-hwmon.c
> > +++ b/drivers/hwmon/dell-smm-hwmon.c
> > @@ -XXX,40 +XXX,80 @@
> > -// Remove procfs interface

I'll take the patch author by their word:

" If you have received this email in error please delete it and
  notify the sender immediately.
"

To the author: Please consider yourself notified, and I will delete the
patch as directed.

Guenter

> On Thursday 23 October 2025 00:07:46 Biancaa Ramesh wrote:
> > The i8k driver currently exposes Dell laptop hardware monitoring
> > information via a deprecated /proc/i8k interface.
> > 
> > This patch removes the procfs file creation and replaces it with
> > standard sysfs attributes under the hwmon subsystem.
> > 
> > - Removes i8k procfs registration and operations.
> > - Creates sysfs attributes for temperature, fan speeds, and power status.
> > - Registers these attributes via devm_hwmon_device_register_with_groups().
> > - Cleans up legacy procfs code for a cleaner, modern, and supported interface.
> > 
> > This migration aligns with Linux kernel best practices to phase out
> > deprecated and legacy procfs files in favor of a structured sysfs approach.
> > 
> > Signed-off-by: Biancaa Ramesh <biancaa2210329@ssn.edu.in>
> > ---
> >  drivers/hwmon/dell-smm-hwmon.c | 100 ++++++++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 100 insertions(+), 40 deletions(-)
> > 
> > diff --git a/drivers/hwmon/dell-smm-hwmon.c b/drivers/hwmon/dell-smm-hwmon.c
> > index oldhash..newhash 100644
> > --- a/drivers/hwmon/dell-smm-hwmon.c
> > +++ b/drivers/hwmon/dell-smm-hwmon.c
> > @@ -XXX,40 +XXX,80 @@
> > -// Remove procfs interface
> > -static int i8k_proc_show(struct seq_file *seq, void *offset)
> > -{
> > -    struct dell_smm_data *data = seq->private;
> > -    // ...
> > -}
> > -
> > -static const struct proc_ops i8k_proc_ops = {
> > -    .proc_open = i8k_open_fs,
> > -    .proc_read = seq_read,
> > -    .proc_lseek = seq_lseek,
> > -    .proc_release = single_release,
> > -    .proc_ioctl = i8k_ioctl,
> > -};
> > -
> > -static void i8k_exit_procfs(void *param)
> > -{
> > -    remove_proc_entry("i8k", NULL);
> > -}
> > -
> > -static void __init i8k_init_procfs(struct device *dev)
> > -{
> > -    struct dell_smm_data *data = dev_get_drvdata(dev);
> > -    // ...
> > -    if (proc_create_data("i8k", 0, NULL, &i8k_proc_ops, data))
> > -        devm_add_action_or_reset(dev, i8k_exit_procfs, NULL);
> > -}
> > +// Define sysfs attributes for temps and fans
> > +static ssize_t temp1_input_show(struct device *dev, struct device_attribute *attr, char *buf)
> > +{
> > +    struct dell_smm_data *data = dev_get_drvdata(dev);
> > +    int temp = i8k_get_temp(data, 0);
> > +    if (temp < 0)
> > +        return temp;
> > +    return sprintf(buf, "%d\n", temp * 1000);
> > +}
> > +
> > +static DEVICE_ATTR_RO(temp1_input);
> > +
> > +static ssize_t fan1_input_show(struct device *dev, struct device_attribute *attr, char *buf)
> > +{
> > +    struct dell_smm_data *data = dev_get_drvdata(dev);
> > +    int speed = i8k_get_fan_speed(data, 0);
> > +    if (speed < 0)
> > +        return speed;
> > +    return sprintf(buf, "%d\n", speed);
> > +}
> > +
> > +static DEVICE_ATTR_RO(fan1_input);
> > +
> > +static struct attribute *dell_smm_attrs[] = {
> > +    &dev_attr_temp1_input.attr,
> > +    &dev_attr_fan1_input.attr,
> > +    NULL,
> > +};
> > +
> > +static const struct attribute_group dell_smm_group = {
> > +    .attrs = dell_smm_attrs,
> > +};
> > +
> > +static const struct attribute_group *dell_smm_groups[] = {
> > +    &dell_smm_group,
> > +    NULL,
> > +};
> > +
> > +static int dell_smm_init_cdev(struct device *dev)
> > +{
> > +    struct dell_smm_data *data = dev_get_drvdata(dev);
> > +    struct device *hwmon_dev;
> > +
> > +    hwmon_dev = devm_hwmon_device_register_with_groups(dev, "dell_smm", data, dell_smm_groups);
> > +    return PTR_ERR_OR_ZERO(hwmon_dev);
> > +}
> > +
> > +static int __init dell_smm_probe(struct platform_device *pdev)
> > +{
> > +    int ret;
> > +
> > +    ret = dell_smm_init_data(&pdev->dev, &i8k_smm_ops);
> > +    if (ret < 0)
> > +        return ret;
> > +
> > +    ret = dell_smm_init_hwmon(&pdev->dev);
> > +    if (ret)
> > +        return ret;
> > +
> > +    ret = dell_smm_init_cdev(&pdev->dev);
> > +    if (ret)
> > +        return ret;
> > +
> > +    return 0;
> > +}
> > 
> > -- 
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