[PATCH] Input: gunze: replace deprecated APIs and fix warning style

[PATCH] Input: gunze: replace deprecated APIs and fix warning style

[Bivash Kumar Singh]

Replace two uses of simple_strtoul() with kstrtoul() as the former
is deprecated. kstrtoul() also properly handles parse errors, so
add an early return if parsing fails.

Replace printk(KERN_WARNING) with dev_warn() using the serio device,
which is the correct logging style for driver code and removes the
redundant 'gunze.c:' filename prefix.

Signed-off-by: Bivash Kumar Singh <bivashraj750@gmail.com>
---
 drivers/input/touchscreen/gunze.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/input/touchscreen/gunze.c b/drivers/input/touchscreen/gunze.c
index 2baeb4f3b941..38450cabdd11 100644
--- a/drivers/input/touchscreen/gunze.c
+++ b/drivers/input/touchscreen/gunze.c
@@ -41,15 +41,19 @@ struct gunze {
 static void gunze_process_packet(struct gunze *gunze)
 {
 	struct input_dev *dev = gunze->dev;
+	unsigned long x, y;
 
 	if (gunze->idx != GUNZE_MAX_LENGTH || gunze->data[5] != ',' ||
 		(gunze->data[0] != 'T' && gunze->data[0] != 'R')) {
-		printk(KERN_WARNING "gunze.c: bad packet: >%.*s<\n", GUNZE_MAX_LENGTH, gunze->data);
+		dev_warn(&gunze->serio->dev, "bad packet: >%.*s<\n", GUNZE_MAX_LENGTH, gunze->data);
 		return;
 	}
 
-	input_report_abs(dev, ABS_X, simple_strtoul(gunze->data + 1, NULL, 10));
-	input_report_abs(dev, ABS_Y, 1024 - simple_strtoul(gunze->data + 6, NULL, 10));
+	if (kstrtoul(gunze->data + 1, 10, &x) || kstrtoul(gunze->data + 6, 10, &y))
+		return;
+
+	input_report_abs(dev, ABS_X, x);
+	input_report_abs(dev, ABS_Y, 1024 - y);
 	input_report_key(dev, BTN_TOUCH, gunze->data[0] == 'T');
 	input_sync(dev);
 }
-- 
2.53.0

Re: [PATCH] Input: gunze: replace deprecated APIs and fix warning style

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Replacing simple_strtoul() with kstrtoul() breaks packet parsing by unconditionally returning an error, dropping all touch events.
--

--- Patch [1]: [PATCH] Input: gunze: replace deprecated APIs and fix warning style ---
commit c6cb2e487b7cdb132629587d8da300e20e580c31
Author: Bivash Kumar Singh <bivashraj750@gmail.com>

Input: gunze: replace deprecated APIs and fix warning style

This commit replaces deprecated simple_strtoul() calls with kstrtoul() and
adds an early return on parsing failures. It also updates the printk warning
to use dev_warn() with the serio device.

> diff --git a/drivers/input/touchscreen/gunze.c b/drivers/input/touchscreen/gunze.c
> index 2baeb4f3b941c..38450cabdd113 100644
> --- a/drivers/input/touchscreen/gunze.c
> +++ b/drivers/input/touchscreen/gunze.c
> @@ -41,15 +41,19 @@ struct gunze {
>  static void gunze_process_packet(struct gunze *gunze)
>  {
[ ... ]
> -	input_report_abs(dev, ABS_X, simple_strtoul(gunze->data + 1, NULL, 10));
> -	input_report_abs(dev, ABS_Y, 1024 - simple_strtoul(gunze->data + 6, NULL, 10));
> +	if (kstrtoul(gunze->data + 1, 10, &x) || kstrtoul(gunze->data + 6, 10, &y))
> +		return;

[Severity: High]
Does this replacement break packet parsing by unconditionally returning an
error?

The kstrtoul() API strictly requires the parsed string to be NUL-terminated
and contain no trailing non-digit characters other than an optional newline.

Because the input data is a comma-separated string like "T1234,5678" and the
buffer is not NUL-terminated, kstrtoul() will encounter the comma when parsing
the X coordinate and return -EINVAL. It will also fail when parsing the Y
coordinate due to the missing NUL terminator.

This early return will unconditionally trigger on every valid touch event,
causing all packets to be dropped and rendering the touchscreen unusable.

> +
> +	input_report_abs(dev, ABS_X, x);
> +	input_report_abs(dev, ABS_Y, 1024 - y);
>  	input_report_key(dev, BTN_TOUCH, gunze->data[0] == 'T');
>  	input_sync(dev);
>  }

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260718190040.10613-1-bivashraj750@gmail.com?part=1

[PATCH v2] Input: gunze: replace deprecated APIs and fix warning style

[Bivash Kumar Singh]

Replace two uses of simple_strtoul() with kstrtoul() as the former
is deprecated. kstrtoul() also properly handles parse errors, so
add an early return if parsing fails.

Replace printk(KERN_WARNING) with dev_warn() using the serio device,
which is the correct logging style for driver code and removes the
redundant 'gunze.c:' filename prefix.

Signed-off-by: Bivash Kumar Singh <bivashraj750@gmail.com>
---
 drivers/input/touchscreen/gunze.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/input/touchscreen/gunze.c b/drivers/input/touchscreen/gunze.c
index 2baeb4f3b941..e9c028430420 100644
--- a/drivers/input/touchscreen/gunze.c
+++ b/drivers/input/touchscreen/gunze.c
@@ -41,15 +41,24 @@ struct gunze {
 static void gunze_process_packet(struct gunze *gunze)
 {
 	struct input_dev *dev = gunze->dev;
+	char buf[GUNZE_MAX_LENGTH + 1];
+	unsigned long x, y;
 
 	if (gunze->idx != GUNZE_MAX_LENGTH || gunze->data[5] != ',' ||
 		(gunze->data[0] != 'T' && gunze->data[0] != 'R')) {
-		printk(KERN_WARNING "gunze.c: bad packet: >%.*s<\n", GUNZE_MAX_LENGTH, gunze->data);
+		dev_warn(&gunze->serio->dev, "bad packet: >%.*s<\n", GUNZE_MAX_LENGTH, gunze->data);
 		return;
 	}
 
-	input_report_abs(dev, ABS_X, simple_strtoul(gunze->data + 1, NULL, 10));
-	input_report_abs(dev, ABS_Y, 1024 - simple_strtoul(gunze->data + 6, NULL, 10));
+	memcpy(buf, gunze->data, GUNZE_MAX_LENGTH);
+	buf[5] = '\0';		/*NULL-terminate X portion: "1234\0" */
+	buf[GUNZE_MAX_LENGTH] = '\0';	/*NULL-terminate Y portion */
+
+	if (kstrtoul(buf + 1, 10, &x) || kstrtoul(buf + 6, 10, &y))
+		return;
+
+	input_report_abs(dev, ABS_X, x);
+	input_report_abs(dev, ABS_Y, 1024 - y);
 	input_report_key(dev, BTN_TOUCH, gunze->data[0] == 'T');
 	input_sync(dev);
 }
-- 
2.53.0

Re: [PATCH v2] Input: gunze: replace deprecated APIs and fix warning style

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Strict parsing with kstrtoul() and an early return drops packets on non-digit coordinate data, potentially causing permanently stuck touch states.
--

--- Patch [1]: [PATCH v2] Input: gunze: replace deprecated APIs and fix warning style ---
commit 448e772e264a7d37aec51432b84a51cdf06f350f
Author: Bivash Kumar Singh <bivashraj750@gmail.com>

Input: gunze: replace deprecated APIs and fix warning style

This commit replaces the deprecated simple_strtoul() API with kstrtoul()
and updates the logging style to use dev_warn(). It also adds an early
return in the packet processing path if coordinate parsing fails.

> diff --git a/drivers/input/touchscreen/gunze.c b/drivers/input/touchscreen/gunze.c
> index 2baeb4f3b941c..e9c028430420c 100644
> --- a/drivers/input/touchscreen/gunze.c
> +++ b/drivers/input/touchscreen/gunze.c
[ ... ]
> @@ -41,15 +41,24 @@ static void gunze_process_packet(struct gunze *gunze)
[ ... ]
> -	input_report_abs(dev, ABS_X, simple_strtoul(gunze->data + 1, NULL, 10));
> -	input_report_abs(dev, ABS_Y, 1024 - simple_strtoul(gunze->data + 6, NULL, 10));
> +	memcpy(buf, gunze->data, GUNZE_MAX_LENGTH);
> +	buf[5] = '\0';		/*NULL-terminate X portion: "1234\0" */
> +	buf[GUNZE_MAX_LENGTH] = '\0';	/*NULL-terminate Y portion */
> +
> +	if (kstrtoul(buf + 1, 10, &x) || kstrtoul(buf + 6, 10, &y))
> +		return;

[Severity: High]
Could this strict parsing with kstrtoul() and early return drop valid events
and cause the touch state to get permanently stuck?

Unlike simple_strtoul(), which stops parsing at the first non-digit character,
kstrtoul() will return an error if the string contains trailing spaces or
serial line noise.

If a touch release packet (starting with 'R') contains non-digit padding,
kstrtoul() will return an error and trigger this early return.

> +
> +	input_report_abs(dev, ABS_X, x);
> +	input_report_abs(dev, ABS_Y, 1024 - y);
>  	input_report_key(dev, BTN_TOUCH, gunze->data[0] == 'T');
>  	input_sync(dev);

Bypassing the BTN_TOUCH state update and input_sync() would cause the
touchscreen to remain stuck in a pressed state until a subsequent valid
packet is received.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260719054121.5917-1-bivashraj750@gmail.com?part=1

[PATCH v3] Input: gunze: replace deprecated APIs and fix warning style

[Bivash Kumar Singh]

Replace two uses of simple_strtoul() with kstrtoul() as the former
is deprecated. kstrtoul() also properly handles parse errors, so
add an early return if parsing fails.

Replace printk(KERN_WARNING) with dev_warn() using the serio device,
which is the correct logging style for driver code and removes the
redundant 'gunze.c:' filename prefix.

Signed-off-by: Bivash Kumar Singh <bivashraj750@gmail.com>

Changes in v3:
  - Fix comment style: add space after /* and use NUL instead of NULL
  - Add missing Changes section that was absent in v2

Changes in v2:
  - Copy packet data to a local NUL-terminated buffer before calling
    kstrtoul(), so the comma separator does not cause parsing to fail
    on every valid touch event. (reported by Sashiko AI review)
---
 drivers/input/touchscreen/gunze.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/input/touchscreen/gunze.c b/drivers/input/touchscreen/gunze.c
index 2baeb4f3b941..0e8131cad647 100644
--- a/drivers/input/touchscreen/gunze.c
+++ b/drivers/input/touchscreen/gunze.c
@@ -41,15 +41,24 @@ struct gunze {
 static void gunze_process_packet(struct gunze *gunze)
 {
 	struct input_dev *dev = gunze->dev;
+	char buf[GUNZE_MAX_LENGTH + 1];
+	unsigned long x, y;
 
 	if (gunze->idx != GUNZE_MAX_LENGTH || gunze->data[5] != ',' ||
 		(gunze->data[0] != 'T' && gunze->data[0] != 'R')) {
-		printk(KERN_WARNING "gunze.c: bad packet: >%.*s<\n", GUNZE_MAX_LENGTH, gunze->data);
+		dev_warn(&gunze->serio->dev, "bad packet: >%.*s<\n", GUNZE_MAX_LENGTH, gunze->data);
 		return;
 	}
 
-	input_report_abs(dev, ABS_X, simple_strtoul(gunze->data + 1, NULL, 10));
-	input_report_abs(dev, ABS_Y, 1024 - simple_strtoul(gunze->data + 6, NULL, 10));
+	memcpy(buf, gunze->data, GUNZE_MAX_LENGTH);
+	buf[5] = '\0';		/* NUL-terminate X portion: "1234\0" */
+	buf[GUNZE_MAX_LENGTH] = '\0';	/* NUL-terminate Y portion */
+
+	if (kstrtoul(buf + 1, 10, &x) || kstrtoul(buf + 6, 10, &y))
+		return;
+
+	input_report_abs(dev, ABS_X, x);
+	input_report_abs(dev, ABS_Y, 1024 - y);
 	input_report_key(dev, BTN_TOUCH, gunze->data[0] == 'T');
 	input_sync(dev);
 }
-- 
2.53.0

Re: [PATCH v3] Input: gunze: replace deprecated APIs and fix warning style

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] The newly added early return on coordinate parsing failure drops critical touch state transitions (like touch releases), causing stuck touches.
--

--- Patch [1]: [PATCH v3] Input: gunze: replace deprecated APIs and fix warning style ---
commit 7585c5c9a9ed51c8709aeaa8875aeb5e7e1646b2
Author: Bivash Kumar Singh <bivashraj750@gmail.com>

Input: gunze: replace deprecated APIs and fix warning style

This commit replaces deprecated simple_strtoul calls with kstrtoul and adds an
early return for parsing failures. It also updates the logging from printk to
dev_warn using the serio device.

> diff --git a/drivers/input/touchscreen/gunze.c b/drivers/input/touchscreen/gunze.c
> index 2baeb4f3b941c..0e8131cad647e 100644
> --- a/drivers/input/touchscreen/gunze.c
> +++ b/drivers/input/touchscreen/gunze.c
> @@ -41,15 +41,24 @@ static void gunze_process_packet(struct gunze *gunze)
>  {
>  	struct input_dev *dev = gunze->dev;
> +	char buf[GUNZE_MAX_LENGTH + 1];
> +	unsigned long x, y;
>  
>  	if (gunze->idx != GUNZE_MAX_LENGTH || gunze->data[5] != ',' ||
>  		(gunze->data[0] != 'T' && gunze->data[0] != 'R')) {
> -		printk(KERN_WARNING "gunze.c: bad packet: >%.*s<\n", GUNZE_MAX_LENGTH, gunze->data);
> +		dev_warn(&gunze->serio->dev, "bad packet: >%.*s<\n", GUNZE_MAX_LENGTH, gunze->data);
>  		return;
>  	}
>  
> -	input_report_abs(dev, ABS_X, simple_strtoul(gunze->data + 1, NULL, 10));
> -	input_report_abs(dev, ABS_Y, 1024 - simple_strtoul(gunze->data + 6, NULL, 10));
> +	memcpy(buf, gunze->data, GUNZE_MAX_LENGTH);
> +	buf[5] = '\0';		/* NUL-terminate X portion: "1234\0" */
> +	buf[GUNZE_MAX_LENGTH] = '\0';	/* NUL-terminate Y portion */
> +
> +	if (kstrtoul(buf + 1, 10, &x) || kstrtoul(buf + 6, 10, &y))
> +		return;

[Severity: High]
Does this early return risk dropping critical touch state transitions, such as
touch releases, causing stuck touches?

If a release packet ('R') contains unparseable coordinates (such as space
padding or noise), parsing will fail and trigger this early return.

Because the return bypasses the input_report_key call for BTN_TOUCH and the
subsequent input_sync call, the release event would be silently dropped.

Could this leave the touchscreen desynchronized and permanently stuck in the
pressed state?

> +
> +	input_report_abs(dev, ABS_X, x);
> +	input_report_abs(dev, ABS_Y, 1024 - y);
>  	input_report_key(dev, BTN_TOUCH, gunze->data[0] == 'T');
>  	input_sync(dev);
>  }

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260719060238.6440-1-bivashraj750@gmail.com?part=1

[PATCH v4] Input: gunze: replace deprecated APIs and fix warning style

[Bivash Kumar Singh]

Replace two uses of simple_strtoul() with kstrtoul() as the former
is deprecated. kstrtoul() requires a NUL-terminated string, so copy
the packet data into a local buffer and NUL-terminate the X and Y
fields before parsing. Initialize x and y to 0 so that if parsing
fails the coordinates fall back to 0 rather than reporting garbage,
and BTN_TOUCH is always updated regardless of parse result.

Replace printk(KERN_WARNING) with dev_warn() using the serio device,
which is the correct logging style for driver code and removes the
redundant 'gunze.c:' filename prefix.

Signed-off-by: Bivash Kumar Singh <bivashraj750@gmail.com>

Changes in v4:
  - Remove early return on kstrtoul() failure to prevent touch state
    getting permanently stuck if a release packet contains noisy data.
    Initialize x and y to 0 as safe fallback values instead.
  - Add dev_warn() on kstrtoul() parse failure so errors are logged
    but BTN_TOUCH is always updated regardless of parse result.
    (reported by Sashiko AI review)

Changes in v3:
  - Fix comment style: add space after /* and use NUL instead of NULL
  - Add missing Changes section that was absent in v2

Changes in v2:
  - Copy packet data to a local NUL-terminated buffer before calling
    kstrtoul(), so the comma separator does not cause parsing to fail
    on every valid touch event. (reported by Sashiko AI review)
---
 drivers/input/touchscreen/gunze.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/drivers/input/touchscreen/gunze.c b/drivers/input/touchscreen/gunze.c
index 2baeb4f3b941..e787209dc965 100644
--- a/drivers/input/touchscreen/gunze.c
+++ b/drivers/input/touchscreen/gunze.c
@@ -41,15 +41,26 @@ struct gunze {
 static void gunze_process_packet(struct gunze *gunze)
 {
 	struct input_dev *dev = gunze->dev;
+	char buf[GUNZE_MAX_LENGTH + 1];
+	unsigned long x = 0, y = 0;
 
 	if (gunze->idx != GUNZE_MAX_LENGTH || gunze->data[5] != ',' ||
 		(gunze->data[0] != 'T' && gunze->data[0] != 'R')) {
-		printk(KERN_WARNING "gunze.c: bad packet: >%.*s<\n", GUNZE_MAX_LENGTH, gunze->data);
+		dev_warn(&gunze->serio->dev, "bad packet: >%.*s<\n", GUNZE_MAX_LENGTH, gunze->data);
 		return;
 	}
 
-	input_report_abs(dev, ABS_X, simple_strtoul(gunze->data + 1, NULL, 10));
-	input_report_abs(dev, ABS_Y, 1024 - simple_strtoul(gunze->data + 6, NULL, 10));
+	memcpy(buf, gunze->data, GUNZE_MAX_LENGTH);
+	buf[5] = '\0';		/* NUL-terminate X portion: "1234\0" */
+	buf[GUNZE_MAX_LENGTH] = '\0';	/* NUL-terminate Y portion */
+
+	if (kstrtoul(buf + 1, 10, &x))
+		dev_warn(&gunze->serio->dev, "failed to parse X coordinate\n");
+	if (kstrtoul(buf + 6, 10, &y))
+		dev_warn(&gunze->serio->dev, "failed to parse Y coordinate\n");
+
+	input_report_abs(dev, ABS_X, x);
+	input_report_abs(dev, ABS_Y, 1024 - y);
 	input_report_key(dev, BTN_TOUCH, gunze->data[0] == 'T');
 	input_sync(dev);
 }
-- 
2.53.0

Re: [PATCH v4] Input: gunze: replace deprecated APIs and fix warning style

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 3 potential issue(s) to consider:

New issues:
- [High] Un-ratelimited dev_warn() calls in the interrupt handler lead to severe kernel log spam (dmesg flooding).
- [High] Replacing simple_strtoul() with kstrtoul() causes a behavioral regression due to strict parsing requirements.

Pre-existing issues:
- [High] Unconditional reporting of fallback coordinates on parse failure causes out-of-bounds values and cursor jumps.
--

--- Patch [1]: [PATCH v4] Input: gunze: replace deprecated APIs and fix warning style ---
commit 7f14b2c0978a817cc80d8103302866bba7c3bf3f
Author: Bivash Kumar Singh <bivashraj750@gmail.com>

Input: gunze: replace deprecated APIs and fix warning style

This commit replaces simple_strtoul() with kstrtoul() by copying the packet
data into a local NUL-terminated buffer first. It also updates the logging
style from printk() to dev_warn().

> diff --git a/drivers/input/touchscreen/gunze.c b/drivers/input/touchscreen/gunze.c
> --- a/drivers/input/touchscreen/gunze.c
> +++ b/drivers/input/touchscreen/gunze.c
> @@ -41,15 +41,26 @@ static void gunze_process_packet(struct gunze *gunze)
>  	struct input_dev *dev = gunze->dev;
> +	char buf[GUNZE_MAX_LENGTH + 1];
> +	unsigned long x = 0, y = 0;
>  
>  	if (gunze->idx != GUNZE_MAX_LENGTH || gunze->data[5] != ',' ||
>  		(gunze->data[0] != 'T' && gunze->data[0] != 'R')) {
> -		printk(KERN_WARNING "gunze.c: bad packet: >%.*s<\n", GUNZE_MAX_LENGTH, gunze->data);
> +		dev_warn(&gunze->serio->dev, "bad packet: >%.*s<\n", GUNZE_MAX_LENGTH, gunze->data);
>  		return;
>  	}
>  
> -	input_report_abs(dev, ABS_X, simple_strtoul(gunze->data + 1, NULL, 10));
> -	input_report_abs(dev, ABS_Y, 1024 - simple_strtoul(gunze->data + 6, NULL, 10));
> +	memcpy(buf, gunze->data, GUNZE_MAX_LENGTH);
> +	buf[5] = '\0';		/* NUL-terminate X portion: "1234\0" */
> +	buf[GUNZE_MAX_LENGTH] = '\0';	/* NUL-terminate Y portion */
> +
> +	if (kstrtoul(buf + 1, 10, &x))

[Severity: High]
In gunze_process_packet(), kstrtoul() requires a perfectly clean string
without trailing spaces or non-digit characters, whereas simple_strtoul()
would successfully stop parsing at the first non-digit.

If the legacy fixed-width hardware protocol pads coordinates with spaces
or contains noisy data, will kstrtoul() reject the entire packet and
return -EINVAL, resulting in a loss of valid touch coordinate data?

> +		dev_warn(&gunze->serio->dev, "failed to parse X coordinate\n");
> +	if (kstrtoul(buf + 6, 10, &y))
> +		dev_warn(&gunze->serio->dev, "failed to parse Y coordinate\n");

[Severity: High]
The commit message mentions that release packets can contain noisy data,
meaning parsing failures are an expected event.

Because gunze_process_packet() is called directly from the hardware interrupt
handler, could these un-ratelimited dev_warn() calls flood the kernel log and
cause high CPU overhead when users interact with the touchscreen?

> +
> +	input_report_abs(dev, ABS_X, x);
> +	input_report_abs(dev, ABS_Y, 1024 - y);

[Severity: High]
This is a pre-existing issue, but when parsing fails, the y coordinate falls
back to 0.

Does unconditionally reporting ABS_Y as 1024 - 0 cause the touch cursor to
instantaneously jump out of bounds and trigger spurious clicks or swipe
artifacts on the device?

>  	input_report_key(dev, BTN_TOUCH, gunze->data[0] == 'T');
>  	input_sync(dev);
>  }

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260719173700.4942-1-bivashraj750@gmail.com?part=1

Re: [PATCH v4] Input: gunze: replace deprecated APIs and fix warning style

[Dmitry Torokhov]

On Sun, Jul 19, 2026 at 11:07:00PM +0530, Bivash Kumar Singh wrote:
> Replace two uses of simple_strtoul() with kstrtoul() as the former
> is deprecated. kstrtoul() requires a NUL-terminated string, so copy
> the packet data into a local buffer and NUL-terminate the X and Y
> fields before parsing. Initialize x and y to 0 so that if parsing
> fails the coordinates fall back to 0 rather than reporting garbage,
> and BTN_TOUCH is always updated regardless of parse result.

Please stop forcing use of kstrtoul() where it is not fit. If you want
to stop using simple_strtoul() then add '\0' when receive '\r' in
gunze_interrupt(), and use

	if (sscanf(gunze->data + 1, "%4u,%4u", &x, &y) != 2) {
		dev_warn_ratelimited(...);
		return;
	}

Thanks.

-- 
Dmitry

[PATCH v5] Input: gunze: replace deprecated APIs and fix warning style

[Bivash Kumar Singh]

Replace printk(KERN_WARNING) with dev_warn_ratelimited() using the
serio device, which is the correct logging style for driver code and
prevents log spam on noisy serial lines.

Replace simple_strtoul() with sscanf() to parse the comma-separated
coordinate data. NUL-terminate the receive buffer in gunze_interrupt()
before calling gunze_process_packet() so sscanf() and the warning
message can safely treat the data as a string.

Signed-off-by: Bivash Kumar Singh <bivashraj750@gmail.com>
---
Changes in v5:
  - Switch from kstrtoul() to sscanf() as suggested by Dmitry Torokhov.
    sscanf() naturally handles comma-separated coordinate data without
    needing a local buffer copy or manual NUL termination tricks.
  - NUL-terminate receive buffer in gunze_interrupt() before processing.
  - Use dev_warn_ratelimited() to prevent log spam on noisy serial lines.

Changes in v4:
  - Remove early return on kstrtoul() failure to prevent touch state
    getting permanently stuck if a release packet contains noisy data.
    Initialize x and y to 0 as safe fallback values instead.
    (reported by Sashiko AI review)

Changes in v3:
  - Fix comment style: add space after /* and use NUL instead of NULL
  - Add missing Changes section that was absent in v2

Changes in v2:
  - Copy packet data to a local NUL-terminated buffer before calling
    kstrtoul(), so the comma separator does not cause parsing to fail
    on every valid touch event. (reported by Sashiko AI review)
---
 drivers/input/touchscreen/gunze.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/input/touchscreen/gunze.c b/drivers/input/touchscreen/gunze.c
index 2baeb4f3b941..7a92052eba80 100644
--- a/drivers/input/touchscreen/gunze.c
+++ b/drivers/input/touchscreen/gunze.c
@@ -41,15 +41,20 @@ struct gunze {
 static void gunze_process_packet(struct gunze *gunze)
 {
 	struct input_dev *dev = gunze->dev;
+	unsigned int x, y;
 
-	if (gunze->idx != GUNZE_MAX_LENGTH || gunze->data[5] != ',' ||
-		(gunze->data[0] != 'T' && gunze->data[0] != 'R')) {
-		printk(KERN_WARNING "gunze.c: bad packet: >%.*s<\n", GUNZE_MAX_LENGTH, gunze->data);
+	if (gunze->data[0] != 'T' && gunze->data[0] != 'R') {
+		dev_warn_ratelimited(&gunze->serio->dev, "bad packet: >%s<\n", gunze->data);
 		return;
 	}
 
-	input_report_abs(dev, ABS_X, simple_strtoul(gunze->data + 1, NULL, 10));
-	input_report_abs(dev, ABS_Y, 1024 - simple_strtoul(gunze->data + 6, NULL, 10));
+	if (sscanf(gunze->data + 1, "%4u,%4u", &x, &y) != 2) {
+		dev_warn_ratelimited(&gunze->serio->dev, "bad packet: >%s<\n", gunze->data);
+		return;
+	}
+
+	input_report_abs(dev, ABS_X, x);
+	input_report_abs(dev, ABS_Y, 1024 - y);
 	input_report_key(dev, BTN_TOUCH, gunze->data[0] == 'T');
 	input_sync(dev);
 }
@@ -60,6 +65,7 @@ static irqreturn_t gunze_interrupt(struct serio *serio,
 	struct gunze *gunze = serio_get_drvdata(serio);
 
 	if (data == '\r') {
+		gunze->data[gunze->idx] = '\0';
 		gunze_process_packet(gunze);
 		gunze->idx = 0;
 	} else {
-- 
2.53.0

Re: [PATCH v5] Input: gunze: replace deprecated APIs and fix warning style

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [High] Off-by-one buffer overflow when NUL-terminating the receive buffer corrupts the device physical path.
- [High] Early return on coordinate parsing failure drops malformed release packets, permanently sticking the touch state.
--

--- Patch [1]: [PATCH v5] Input: gunze: replace deprecated APIs and fix warning style ---
commit e46d9a0baa3ae281ee5b9c02aad4e7f63a5cf33f
Author: Bivash Kumar Singh <bivashraj750@gmail.com>

Input: gunze: replace deprecated APIs and fix warning style

This commit updates the driver to use dev_warn_ratelimited() instead of
printk() and replaces simple_strtoul() with sscanf() for parsing coordinate
data. It also NUL-terminates the receive buffer to allow safe string parsing.

> diff --git a/drivers/input/touchscreen/gunze.c b/drivers/input/touchscreen/gunze.c
> index 2baeb4f3b941c..7a92052eba805 100644
> --- a/drivers/input/touchscreen/gunze.c
> +++ b/drivers/input/touchscreen/gunze.c
> @@ -41,15 +41,20 @@ struct gunze {
>  static void gunze_process_packet(struct gunze *gunze)
>  {
>  	struct input_dev *dev = gunze->dev;
> +	unsigned int x, y;
>  
> -	if (gunze->idx != GUNZE_MAX_LENGTH || gunze->data[5] != ',' ||
> -		(gunze->data[0] != 'T' && gunze->data[0] != 'R')) {
> -		printk(KERN_WARNING "gunze.c: bad packet: >%.*s<\n", GUNZE_MAX_LENGTH, gunze->data);
> +	if (gunze->data[0] != 'T' && gunze->data[0] != 'R') {
> +		dev_warn_ratelimited(&gunze->serio->dev, "bad packet: >%s<\n", gunze->data);
>  		return;
>  	}
>  
> -	input_report_abs(dev, ABS_X, simple_strtoul(gunze->data + 1, NULL, 10));
> -	input_report_abs(dev, ABS_Y, 1024 - simple_strtoul(gunze->data + 6, NULL, 10));
> +	if (sscanf(gunze->data + 1, "%4u,%4u", &x, &y) != 2) {
> +		dev_warn_ratelimited(&gunze->serio->dev, "bad packet: >%s<\n", gunze->data);
> +		return;
> +	}

[Severity: High]
Does this early return risk leaving the touch state permanently stuck?

If a release packet (starting with 'R') is received but the coordinate data
contains noise causing sscanf() to fail, this will return early and skip the
input_report_key() call below, dropping the release event.

> +
> +	input_report_abs(dev, ABS_X, x);
> +	input_report_abs(dev, ABS_Y, 1024 - y);
>  	input_report_key(dev, BTN_TOUCH, gunze->data[0] == 'T');
>  	input_sync(dev);
>  }
> @@ -60,6 +65,7 @@ static irqreturn_t gunze_interrupt(struct serio *serio,
>  	struct gunze *gunze = serio_get_drvdata(serio);
>  
>  	if (data == '\r') {
> +		gunze->data[gunze->idx] = '\0';

[Severity: High]
Can this write past the end of the data array and corrupt the physical path?

The data array in struct gunze is sized exactly to GUNZE_MAX_LENGTH (10):

struct gunze {
	...
	unsigned char data[GUNZE_MAX_LENGTH];
	char phys[32];
};

When a full-length valid touch packet is received followed by a '\r',
gunze->idx will be 10. Writing '\0' at this index will write out of bounds
and overwrite the adjacent phys array. Could the array size be increased to
accommodate the NUL terminator?

>  		gunze_process_packet(gunze);
>  		gunze->idx = 0;
>  	} else {

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260720032407.4644-1-bivashraj750@gmail.com?part=1