Lantiq PEF2256 framer has some little differences in behaviour
depending on its version.

Add a sysfs attribute to allow user applications to know the
version.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
v2:
- Make DEVICE_ATTR_RO(version) static
- Split version_show() prototype into 2 lines to remain under 80 chars

v1: https://lore.kernel.org/all/f9aaa89946f1417dc0a5e852702410453e816dbc.1757754689.git.christophe.leroy@csgroup.eu/
---
 drivers/net/wan/framer/pef2256/pef2256.c | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

diff --git a/drivers/net/wan/framer/pef2256/pef2256.c b/drivers/net/wan/framer/pef2256/pef2256.c
index 1e4c8e85d598..a2166b424428 100644
--- a/drivers/net/wan/framer/pef2256/pef2256.c
+++ b/drivers/net/wan/framer/pef2256/pef2256.c
@@ -37,6 +37,7 @@ struct pef2256 {
 	struct device *dev;
 	struct regmap *regmap;
 	enum pef2256_version version;
+	const char *version_txt;
 	struct clk *mclk;
 	struct clk *sclkr;
 	struct clk *sclkx;
@@ -114,6 +115,16 @@ enum pef2256_version pef2256_get_version(struct pef2256 *pef2256)
 }
 EXPORT_SYMBOL_GPL(pef2256_get_version);
 
+static ssize_t version_show(struct device *dev, struct device_attribute *attr,
+			    char *buf)
+{
+	struct pef2256 *pef2256 = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%s\n", pef2256->version_txt);
+}
+
+static DEVICE_ATTR_RO(version);
+
 enum pef2256_gcm_config_item {
 	PEF2256_GCM_CONFIG_1544000 = 0,
 	PEF2256_GCM_CONFIG_2048000,
@@ -697,7 +708,6 @@ static int pef2256_probe(struct platform_device *pdev)
 	unsigned long sclkr_rate, sclkx_rate;
 	struct framer_provider *framer_provider;
 	struct pef2256 *pef2256;
-	const char *version_txt;
 	void __iomem *iomem;
 	int ret;
 	int irq;
@@ -763,18 +773,18 @@ static int pef2256_probe(struct platform_device *pdev)
 	pef2256->version = pef2256_get_version(pef2256);
 	switch (pef2256->version) {
 	case PEF2256_VERSION_1_2:
-		version_txt = "1.2";
+		pef2256->version_txt = "1.2";
 		break;
 	case PEF2256_VERSION_2_1:
-		version_txt = "2.1";
+		pef2256->version_txt = "2.1";
 		break;
 	case PEF2256_VERSION_2_2:
-		version_txt = "2.2";
+		pef2256->version_txt = "2.2";
 		break;
 	default:
 		return -ENODEV;
 	}
-	dev_info(pef2256->dev, "Version %s detected\n", version_txt);
+	dev_info(pef2256->dev, "Version %s detected\n", pef2256->version_txt);
 
 	ret = pef2556_of_parse(pef2256, np);
 	if (ret)
@@ -835,6 +845,8 @@ static int pef2256_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	device_create_file(pef2256->dev, &dev_attr_version);
+
 	return 0;
 }
 
@@ -849,6 +861,8 @@ static void pef2256_remove(struct platform_device *pdev)
 	pef2256_write8(pef2256, PEF2256_IMR3, 0xff);
 	pef2256_write8(pef2256, PEF2256_IMR4, 0xff);
 	pef2256_write8(pef2256, PEF2256_IMR5, 0xff);
+
+	device_remove_file(pef2256->dev, &dev_attr_version);
 }
 
 static const struct of_device_id pef2256_id_table[] = {
-- 
2.49.0

Hi Christophe,

On Wed, 17 Sep 2025 08:24:01 +0200
Christophe Leroy <christophe.leroy@csgroup.eu> wrote:

> Lantiq PEF2256 framer has some little differences in behaviour
> depending on its version.
> 
> Add a sysfs attribute to allow user applications to know the
> version.
> 
> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
> ---
> v2:
> - Make DEVICE_ATTR_RO(version) static
> - Split version_show() prototype into 2 lines to remain under 80 chars
> 
> v1: https://lore.kernel.org/all/f9aaa89946f1417dc0a5e852702410453e816dbc.1757754689.git.christophe.leroy@csgroup.eu/
> ---
>  drivers/net/wan/framer/pef2256/pef2256.c | 24 +++++++++++++++++++-----
>  1 file changed, 19 insertions(+), 5 deletions(-)
> 

This patch add a new entry in sysfs.

Can you provide the related documentation in /Documentation/ABI/testing/

Best regards,
Hervé

On Wed, Sep 17, 2025 at 08:24:01AM +0200, Christophe Leroy wrote:
> Lantiq PEF2256 framer has some little differences in behaviour
> depending on its version.
> 
> Add a sysfs attribute to allow user applications to know the
> version.
> 
> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
> ---
> v2:
> - Make DEVICE_ATTR_RO(version) static
> - Split version_show() prototype into 2 lines to remain under 80 chars

Thanks for these updates. Sparse and checkpatch are happy now.

> 
> v1: https://lore.kernel.org/all/f9aaa89946f1417dc0a5e852702410453e816dbc.1757754689.git.christophe.leroy@csgroup.eu/

...