[PATCH] hwmon: pmbus: ibm-cffps: avoid format truncation warnings

[PATCH] hwmon: pmbus: ibm-cffps: avoid format truncation warnings

[Eduard Zateev]

Building with W=1 reports format truncation warnings when formatting
the firmware version values for debugfs.

The SMBus helpers return the byte and word values as int, so the
compiler cannot infer that the formatted values fit into the small
temporary buffers. Cast the values to u8 and u16 before formatting
them.

This avoids the -Wformat-truncation warnings while keeping the existing
output format unchanged.

Signed-off-by: Eduard Zateev <hackerowskiy@gmail.com>
---
 drivers/hwmon/pmbus/ibm-cffps.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/pmbus/ibm-cffps.c b/drivers/hwmon/pmbus/ibm-cffps.c
index aad94bcb9ceb..2498c6f4778e 100644
--- a/drivers/hwmon/pmbus/ibm-cffps.c
+++ b/drivers/hwmon/pmbus/ibm-cffps.c
@@ -166,7 +166,7 @@ static ssize_t ibm_cffps_debugfs_read(struct file *file, char __user *buf,
 				if (rc < 0)
 					goto unlock;
 
-				snprintf(&data[i * 2], 3, "%02X", rc);
+				snprintf(&data[i * 2], 3, "%02X", (u8)rc);
 			}
 
 			rc = i * 2;
@@ -177,7 +177,7 @@ static ssize_t ibm_cffps_debugfs_read(struct file *file, char __user *buf,
 				if (rc < 0)
 					goto unlock;
 
-				snprintf(&data[i * 4], 5, "%04X", rc);
+				snprintf(&data[i * 4], 5, "%04X", (u16)rc);
 			}
 
 			rc = i * 4;
-- 
2.55.0

Re: [PATCH] hwmon: pmbus: ibm-cffps: avoid format truncation warnings

[sashiko-bot]

> Building with W=1 reports format truncation warnings when formatting
> the firmware version values for debugfs.
> 
> The SMBus helpers return the byte and word values as int, so the
> compiler cannot infer that the formatted values fit into the small
> temporary buffers. Cast the values to u8 and u16 before formatting
> them.
> 
> This avoids the -Wformat-truncation warnings while keeping the existing
> output format unchanged.
> 
> Signed-off-by: Eduard Zateev <hackerowskiy@gmail.com>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260923024827.56445-1-hackerowskiy@gmail.com?part=1

Re: [PATCH] hwmon: pmbus: ibm-cffps: avoid format truncation warnings

[Guenter Roeck]

On Wed, Sep 23, 2026 at 04:48:27AM +0200, Eduard Zateev wrote:
> Building with W=1 reports format truncation warnings when formatting
> the firmware version values for debugfs.
> 
> The SMBus helpers return the byte and word values as int, so the
> compiler cannot infer that the formatted values fit into the small
> temporary buffers. Cast the values to u8 and u16 before formatting
> them.
> 
> This avoids the -Wformat-truncation warnings while keeping the existing
> output format unchanged.
> 
> Signed-off-by: Eduard Zateev <hackerowskiy@gmail.com>

Applied.

Thanks,
Guenter