Some SoC drivers reimplement the functionality of
soc_device_get_machine(). Make this function accessible through the
sys_soc.h header. Rework it slightly to return a negative error number
on failure to read the machine string (SoC core can keep on ignoring
it). While at it: make it use the __free() helper from cleanup.h.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
---
 drivers/base/soc.c      | 16 +++++++++-------
 include/linux/sys_soc.h | 10 ++++++++++
 2 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/drivers/base/soc.c b/drivers/base/soc.c
index 6f42632d2b0fcc8a729484e6ad270f9bcabe4a0b..bec8771d40f0590d4d7c3985c08fedfd4043a394 100644
--- a/drivers/base/soc.c
+++ b/drivers/base/soc.c
@@ -5,6 +5,7 @@
  * Author: Lee Jones <lee.jones@linaro.org> for ST-Ericsson.
  */
 
+#include <linux/cleanup.h>
 #include <linux/err.h>
 #include <linux/glob.h>
 #include <linux/idr.h>
@@ -111,17 +112,18 @@ static void soc_release(struct device *dev)
 	kfree(soc_dev);
 }
 
-static void soc_device_get_machine(struct soc_device_attribute *soc_dev_attr)
+int soc_device_get_machine(struct soc_device_attribute *soc_dev_attr)
 {
-	struct device_node *np;
-
 	if (soc_dev_attr->machine)
-		return;
+		return -EBUSY;
+
+	struct device_node *np __free(device_node) = of_find_node_by_path("/");
+	if (!np)
+		return -ENOENT;
 
-	np = of_find_node_by_path("/");
-	of_property_read_string(np, "model", &soc_dev_attr->machine);
-	of_node_put(np);
+	return of_property_read_string(np, "model", &soc_dev_attr->machine);
 }
+EXPORT_SYMBOL_GPL(soc_device_get_machine);
 
 static struct soc_device_attribute *early_soc_dev_attr;
 
diff --git a/include/linux/sys_soc.h b/include/linux/sys_soc.h
index d9b3cf0f410c8cfb509a4c1a4d6c83fde6fe33c6..2d2dbc18462a39ddee95e38826a769fab089026f 100644
--- a/include/linux/sys_soc.h
+++ b/include/linux/sys_soc.h
@@ -37,6 +37,16 @@ void soc_device_unregister(struct soc_device *soc_dev);
  */
 struct device *soc_device_to_device(struct soc_device *soc);
 
+/**
+ * soc_device_get_machine - retrieve the machine model and store it in
+ *                          the soc_device_attribute structure
+ * @soc_dev_attr: SoC attribute structure to store the model in
+ *
+ * Returns:
+ * 0 on success, negative error number on failure.
+ */
+int soc_device_get_machine(struct soc_device_attribute *soc_dev_attr);
+
 #ifdef CONFIG_SOC_BUS
 const struct soc_device_attribute *soc_device_match(
 	const struct soc_device_attribute *matches);

-- 
2.47.3

Hi Bartosz,

On Mon, 19 Jan 2026 at 11:40, Bartosz Golaszewski
<bartosz.golaszewski@oss.qualcomm.com> wrote:
> Some SoC drivers reimplement the functionality of
> soc_device_get_machine(). Make this function accessible through the
> sys_soc.h header. Rework it slightly to return a negative error number
> on failure to read the machine string (SoC core can keep on ignoring
> it). While at it: make it use the __free() helper from cleanup.h.
>
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>

Thanks for your patch!

> --- a/drivers/base/soc.c
> +++ b/drivers/base/soc.c
> @@ -5,6 +5,7 @@
>   * Author: Lee Jones <lee.jones@linaro.org> for ST-Ericsson.
>   */
>
> +#include <linux/cleanup.h>
>  #include <linux/err.h>
>  #include <linux/glob.h>
>  #include <linux/idr.h>
> @@ -111,17 +112,18 @@ static void soc_release(struct device *dev)
>         kfree(soc_dev);
>  }
>
> -static void soc_device_get_machine(struct soc_device_attribute *soc_dev_attr)
> +int soc_device_get_machine(struct soc_device_attribute *soc_dev_attr)
>  {
> -       struct device_node *np;
> -
>         if (soc_dev_attr->machine)
> -               return;
> +               return -EBUSY;
> +
> +       struct device_node *np __free(device_node) = of_find_node_by_path("/");
> +       if (!np)
> +               return -ENOENT;
>
> -       np = of_find_node_by_path("/");
> -       of_property_read_string(np, "model", &soc_dev_attr->machine);
> -       of_node_put(np);
> +       return of_property_read_string(np, "model", &soc_dev_attr->machine);

I am not so fond of these of_find_node_by_path("/") + something replacements.
What about adding an of_machine_get_model() helper?

>  }
> +EXPORT_SYMBOL_GPL(soc_device_get_machine);
>
>  static struct soc_device_attribute *early_soc_dev_attr;
>

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

On Mon Jan 19, 2026 at 11:40 AM CET, Bartosz Golaszewski wrote:
> -static void soc_device_get_machine(struct soc_device_attribute *soc_dev_attr)
> +int soc_device_get_machine(struct soc_device_attribute *soc_dev_attr)
>  {
> -	struct device_node *np;
> -
>  	if (soc_dev_attr->machine)
> -		return;
> +		return -EBUSY;
> +
> +	struct device_node *np __free(device_node) = of_find_node_by_path("/");
> +	if (!np)
> +		return -ENOENT;

This should never fail at this point, no? Also, can't we just use of_root?

>  
> -	np = of_find_node_by_path("/");
> -	of_property_read_string(np, "model", &soc_dev_attr->machine);
> -	of_node_put(np);
> +	return of_property_read_string(np, "model", &soc_dev_attr->machine);
>  }
> +EXPORT_SYMBOL_GPL(soc_device_get_machine);

If we want to export this, we shouldn't reuse the existing name, which is
misleading.

soc_device_get_machine() reads as if we return a reference count of something.
Additionally, it operates on struct soc_device_attribute instead of struct
soc_device, where the name suggests the latter.

Instead this should be soc_device_attribute_read_machine() or if we want a
shorter name, just soc_attr_read_machine().

On Mon Jan 19, 2026 at 12:36 PM CET, Danilo Krummrich wrote:
> On Mon Jan 19, 2026 at 11:40 AM CET, Bartosz Golaszewski wrote:
>> -static void soc_device_get_machine(struct soc_device_attribute *soc_dev_attr)
>> +int soc_device_get_machine(struct soc_device_attribute *soc_dev_attr)
>>  {
>> -	struct device_node *np;
>> -
>>  	if (soc_dev_attr->machine)
>> -		return;
>> +		return -EBUSY;
>> +
>> +	struct device_node *np __free(device_node) = of_find_node_by_path("/");
>> +	if (!np)
>> +		return -ENOENT;
>
> This should never fail at this point, no? Also, can't we just use of_root?

Regarding of_root, please disregard my earlier comment. I mistakenly assumed
that it would also be guarded by CONFIG_OF.

But I still think we do not need the NULL check.

>> -	np = of_find_node_by_path("/");
>> -	of_property_read_string(np, "model", &soc_dev_attr->machine);
>> -	of_node_put(np);
>> +	return of_property_read_string(np, "model", &soc_dev_attr->machine);
>>  }
>> +EXPORT_SYMBOL_GPL(soc_device_get_machine);
>
> If we want to export this, we shouldn't reuse the existing name, which is
> misleading.
>
> soc_device_get_machine() reads as if we return a reference count of something.
> Additionally, it operates on struct soc_device_attribute instead of struct
> soc_device, where the name suggests the latter.
>
> Instead this should be soc_device_attribute_read_machine() or if we want a
> shorter name, just soc_attr_read_machine().

Le 19/01/2026 à 11:40, Bartosz Golaszewski a écrit :
> Some SoC drivers reimplement the functionality of
> soc_device_get_machine(). Make this function accessible through the
> sys_soc.h header. Rework it slightly to return a negative error number
> on failure to read the machine string (SoC core can keep on ignoring
> it). While at it: make it use the __free() helper from cleanup.h.
> 
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>

Reviewed-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>

> ---
>   drivers/base/soc.c      | 16 +++++++++-------
>   include/linux/sys_soc.h | 10 ++++++++++
>   2 files changed, 19 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/base/soc.c b/drivers/base/soc.c
> index 6f42632d2b0fcc8a729484e6ad270f9bcabe4a0b..bec8771d40f0590d4d7c3985c08fedfd4043a394 100644
> --- a/drivers/base/soc.c
> +++ b/drivers/base/soc.c
> @@ -5,6 +5,7 @@
>    * Author: Lee Jones <lee.jones@linaro.org> for ST-Ericsson.
>    */
>   
> +#include <linux/cleanup.h>
>   #include <linux/err.h>
>   #include <linux/glob.h>
>   #include <linux/idr.h>
> @@ -111,17 +112,18 @@ static void soc_release(struct device *dev)
>   	kfree(soc_dev);
>   }
>   
> -static void soc_device_get_machine(struct soc_device_attribute *soc_dev_attr)
> +int soc_device_get_machine(struct soc_device_attribute *soc_dev_attr)
>   {
> -	struct device_node *np;
> -
>   	if (soc_dev_attr->machine)
> -		return;
> +		return -EBUSY;
> +
> +	struct device_node *np __free(device_node) = of_find_node_by_path("/");
> +	if (!np)
> +		return -ENOENT;
>   
> -	np = of_find_node_by_path("/");
> -	of_property_read_string(np, "model", &soc_dev_attr->machine);
> -	of_node_put(np);
> +	return of_property_read_string(np, "model", &soc_dev_attr->machine);
>   }
> +EXPORT_SYMBOL_GPL(soc_device_get_machine);
>   
>   static struct soc_device_attribute *early_soc_dev_attr;
>   
> diff --git a/include/linux/sys_soc.h b/include/linux/sys_soc.h
> index d9b3cf0f410c8cfb509a4c1a4d6c83fde6fe33c6..2d2dbc18462a39ddee95e38826a769fab089026f 100644
> --- a/include/linux/sys_soc.h
> +++ b/include/linux/sys_soc.h
> @@ -37,6 +37,16 @@ void soc_device_unregister(struct soc_device *soc_dev);
>    */
>   struct device *soc_device_to_device(struct soc_device *soc);
>   
> +/**
> + * soc_device_get_machine - retrieve the machine model and store it in
> + *                          the soc_device_attribute structure
> + * @soc_dev_attr: SoC attribute structure to store the model in
> + *
> + * Returns:
> + * 0 on success, negative error number on failure.
> + */
> +int soc_device_get_machine(struct soc_device_attribute *soc_dev_attr);
> +
>   #ifdef CONFIG_SOC_BUS
>   const struct soc_device_attribute *soc_device_match(
>   	const struct soc_device_attribute *matches);
>