[PATCH] drm,fbdev: td043mtea1: Convert sprintf() family to sysfs_emit() family

[PATCH] drm,fbdev: td043mtea1: Convert sprintf() family to sysfs_emit() family

[Li Zhijian]

Per filesystems/sysfs.rst, show() should only use sysfs_emit()
or sysfs_emit_at() when formatting the value to be returned to user space.

coccinelle complains that there are still a couple of functions that use
snprintf(). Convert them to sysfs_emit().

sprintf() and scnprintf() will be converted as well if they have.

Generally, this patch is generated by
make coccicheck M=<path/to/file> MODE=patch \
COCCI=scripts/coccinelle/api/device_attr_show.cocci

No functional change intended

CC: Neil Armstrong <neil.armstrong@linaro.org>
CC: Jessica Zhang <quic_jesszhan@quicinc.com>
CC: Sam Ravnborg <sam@ravnborg.org>
CC: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
CC: Maxime Ripard <mripard@kernel.org>
CC: Thomas Zimmermann <tzimmermann@suse.de>
CC: David Airlie <airlied@gmail.com>
CC: Daniel Vetter <daniel@ffwll.ch>
CC: Helge Deller <deller@gmx.de>
CC: linux-omap@vger.kernel.org
CC: linux-fbdev@vger.kernel.org
CC: dri-devel@lists.freedesktop.org
Signed-off-by: Li Zhijian <lizhijian@fujitsu.com>
---
This is a part of the work "Fix coccicheck device_attr_show warnings"[1]
Split them per subsystem so that the maintainer can review it easily
[1] https://lore.kernel.org/lkml/20240116041129.3937800-1-lizhijian@fujitsu.com/
---
 drivers/gpu/drm/panel/panel-tpo-td043mtea1.c        | 13 ++++---------
 .../omap2/omapfb/displays/panel-tpo-td043mtea1.c    | 12 ++++--------
 2 files changed, 8 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/panel/panel-tpo-td043mtea1.c b/drivers/gpu/drm/panel/panel-tpo-td043mtea1.c
index cf4609bb9b1d..0983fe47eb5a 100644
--- a/drivers/gpu/drm/panel/panel-tpo-td043mtea1.c
+++ b/drivers/gpu/drm/panel/panel-tpo-td043mtea1.c
@@ -242,16 +242,11 @@ static ssize_t gamma_show(struct device *dev, struct device_attribute *attr,
 	struct td043mtea1_panel *lcd = dev_get_drvdata(dev);
 	ssize_t len = 0;
 	unsigned int i;
-	int ret;
 
-	for (i = 0; i < ARRAY_SIZE(lcd->gamma); i++) {
-		ret = snprintf(buf + len, PAGE_SIZE - len, "%u ",
-			       lcd->gamma[i]);
-		if (ret < 0)
-			return ret;
-		len += ret;
-	}
-	buf[len - 1] = '\n';
+	for (i = 0; i < ARRAY_SIZE(lcd->gamma); i++)
+		len += sysfs_emit_at(buf, len, "%u ", lcd->gamma[i]);
+	if (len)
+		buf[len - 1] = '\n';
 
 	return len;
 }
diff --git a/drivers/video/fbdev/omap2/omapfb/displays/panel-tpo-td043mtea1.c b/drivers/video/fbdev/omap2/omapfb/displays/panel-tpo-td043mtea1.c
index 477789cff8e0..040a17a05baa 100644
--- a/drivers/video/fbdev/omap2/omapfb/displays/panel-tpo-td043mtea1.c
+++ b/drivers/video/fbdev/omap2/omapfb/displays/panel-tpo-td043mtea1.c
@@ -228,14 +228,10 @@ static ssize_t tpo_td043_gamma_show(struct device *dev,
 	int ret;
 	int i;
 
-	for (i = 0; i < ARRAY_SIZE(ddata->gamma); i++) {
-		ret = snprintf(buf + len, PAGE_SIZE - len, "%u ",
-				ddata->gamma[i]);
-		if (ret < 0)
-			return ret;
-		len += ret;
-	}
-	buf[len - 1] = '\n';
+	for (i = 0; i < ARRAY_SIZE(ddata->gamma); i++)
+		len = sysfs_emit_at(buf, len, "%u ", ddata->gamma[i]);
+	if (len)
+		buf[len - 1] = '\n';
 
 	return len;
 }
-- 
2.29.2

Re: [PATCH] drm,fbdev: td043mtea1: Convert sprintf() family to sysfs_emit() family

[Zhijian Li (Fujitsu)]

On 19/03/2024 11:43, Li Zhijian wrote:
> diff --git
> a/drivers/video/fbdev/omap2/omapfb/displays/panel-tpo-td043mtea1.c
> b/drivers/video/fbdev/omap2/omapfb/displays/panel-tpo-td043mtea1.c
> index 477789cff8e0..040a17a05baa 100644
> --- a/drivers/video/fbdev/omap2/omapfb/displays/panel-tpo-td043mtea1.c
> +++ b/drivers/video/fbdev/omap2/omapfb/displays/panel-tpo-td043mtea1.c
> @@ -228,14 +228,10 @@ static ssize_t tpo_td043_gamma_show(struct device
> *dev,
>   	int ret;
>   	int i;
>   
> -	for (i = 0; i < ARRAY_SIZE(ddata->gamma); i++) {
> -		ret = snprintf(buf + len, PAGE_SIZE - len, "%u ",
> -				ddata->gamma[i]);
> -		if (ret < 0)
> -			return ret;
> -		len += ret;
> -	}
> -	buf[len - 1] = '\n';
> +	for (i = 0; i < ARRAY_SIZE(ddata->gamma); i++)
> +		len = sysfs_emit_at(buf, len, "%u ", ddata->gamma[i]);

It should be
		len += sysfs_emit_at(buf, len, "%u ", ddata->gamma[i]);

just posted V2 to fix this.


Thanks
Zhijian

> +	if (len)
> +		buf[len - 1] = '\n';
>