On Mon, Jan 10, 2022 at 06:22:56PM +0000, Paul Cercueil wrote:
> If a label is defined in the device tree for this device add that
> to the device specific attributes. This is useful for userspace to
> be able to identify an individual device when multiple identical
> chips are present in the system.
>
> Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
> Tested-by: Cosmin Tanislav <cosmin.tanislav@xxxxxxxxxx>
Applied to hwmon-next.
Thanks,
Guenter
> ---
>
> Notes:
> v2: - Cache label into hwmon_device
> - Rename hwmon_dev_name_is_visible() to hwmon_dev_attr_is_visible()
> v3: Move the code setting the label around in the probe function to fix
> error handling issue.
>
> drivers/hwmon/hwmon.c | 34 +++++++++++++++++++++++++++++++---
> 1 file changed, 31 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/hwmon/hwmon.c b/drivers/hwmon/hwmon.c
> index 3501a3ead4ba..8d787dba3e38 100644
> --- a/drivers/hwmon/hwmon.c
> +++ b/drivers/hwmon/hwmon.c
> @@ -18,6 +18,7 @@
> #include <linux/list.h>
> #include <linux/module.h>
> #include <linux/pci.h>
> +#include <linux/property.h>
> #include <linux/slab.h>
> #include <linux/string.h>
> #include <linux/thermal.h>
> @@ -30,6 +31,7 @@
>
> struct hwmon_device {
> const char *name;
> + const char *label;
> struct device dev;
> const struct hwmon_chip_info *chip;
> struct list_head tzdata;
> @@ -71,17 +73,29 @@ name_show(struct device *dev, struct device_attribute *attr, char *buf)
> }
> static DEVICE_ATTR_RO(name);
>
> +static ssize_t
> +label_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> + return sysfs_emit(buf, "%s\n", to_hwmon_device(dev)->label);
> +}
> +static DEVICE_ATTR_RO(label);
> +
> static struct attribute *hwmon_dev_attrs[] = {
> &dev_attr_name.attr,
> + &dev_attr_label.attr,
> NULL
> };
>
> -static umode_t hwmon_dev_name_is_visible(struct kobject *kobj,
> +static umode_t hwmon_dev_attr_is_visible(struct kobject *kobj,
> struct attribute *attr, int n)
> {
> struct device *dev = kobj_to_dev(kobj);
> + struct hwmon_device *hdev = to_hwmon_device(dev);
>
> - if (to_hwmon_device(dev)->name == NULL)
> + if (attr == &dev_attr_name.attr && hdev->name == NULL)
> + return 0;
> +
> + if (attr == &dev_attr_label.attr && hdev->label == NULL)
> return 0;
>
> return attr->mode;
> @@ -89,7 +103,7 @@ static umode_t hwmon_dev_name_is_visible(struct kobject *kobj,
>
> static const struct attribute_group hwmon_dev_attr_group = {
> .attrs = hwmon_dev_attrs,
> - .is_visible = hwmon_dev_name_is_visible,
> + .is_visible = hwmon_dev_attr_is_visible,
> };
>
> static const struct attribute_group *hwmon_dev_attr_groups[] = {
> @@ -117,6 +131,7 @@ static void hwmon_dev_release(struct device *dev)
> if (hwdev->group.attrs)
> hwmon_free_attrs(hwdev->group.attrs);
> kfree(hwdev->groups);
> + kfree(hwdev->label);
> kfree(hwdev);
> }
>
> @@ -733,6 +748,7 @@ __hwmon_device_register(struct device *dev, const char *name, void *drvdata,
> const struct attribute_group **groups)
> {
> struct hwmon_device *hwdev;
> + const char *label;
> struct device *hdev;
> int i, err, id;
>
> @@ -788,6 +804,18 @@ __hwmon_device_register(struct device *dev, const char *name, void *drvdata,
> hdev->groups = groups;
> }
>
> + if (device_property_present(dev, "label")) {
> + err = device_property_read_string(dev, "label", &label);
> + if (err < 0)
> + goto free_hwmon;
> +
> + hwdev->label = kstrdup(label, GFP_KERNEL);
> + if (hwdev->label == NULL) {
> + err = -ENOMEM;
> + goto free_hwmon;
> + }
> + }
> +
> hwdev->name = name;
> hdev->class = &hwmon_class;
> hdev->parent = dev;
