Message-ID: <20251022183746.66481-1-biancaa2210329@ssn.edu.in>
Date: Thu, 23 Oct 2025 00:07:46 +0530
From: Biancaa Ramesh <biancaa2210329@....edu.in>
To: pali@...nel.org
Cc: linux@...ck-us.net,
	linux-hwmon@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Biancaa Ramesh <biancaa2210329@....edu.in>
Subject: [PATCH v1] hwmon: migrate i8k procfs interface to sysfs

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@....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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