linux-kernel - [PATCH 1/3] fbtft: Make sysfs and dev_*() logging conditional on FB

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Message-ID: <20251209042744.7875-2-chintanlike@gmail.com>
Date: Mon,  8 Dec 2025 20:27:42 -0800
From: Chintan Patel <chintanlike@...il.com>
To: linux-fbdev@...r.kernel.org,
	linux-staging@...ts.linux.dev,
	linux-omap@...r.kernel.org
Cc: linux-kernel@...r.kernel.org,
	dri-devel@...ts.freedesktop.org,
	tzimmermann@...e.de,
	andy@...nel.org,
	deller@....de,
	gregkh@...uxfoundation.org,
	Chintan Patel <chintanlike@...il.com>
Subject: [PATCH 1/3] fbtft: Make sysfs and dev_*() logging conditional on FB_DEVICE

The fbtft core and sysfs implementation unconditionally dereference
fb_info->dev and register sysfs attributes. When FB_DEVICE=n, these
fields are unavailable, leading to build failures.

This patch wraps all sysfs attribute creation/removal and dev_dbg/dev_info
logging in #ifdef CONFIG_FB_DEVICE, with pr_*() fallbacks for the
non-FB_DEVICE case. This makes fbtft fully buildable when FB_DEVICE is
disabled.

Signed-off-by: Chintan Patel <chintanlike@...il.com>
---
 drivers/staging/fbtft/fbtft-core.c  | 20 ++++++++++++++++++--
 drivers/staging/fbtft/fbtft-sysfs.c |  8 ++++++++
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/fbtft/fbtft-core.c b/drivers/staging/fbtft/fbtft-core.c
index 9e7b84071174..dc967bdeabe8 100644
--- a/drivers/staging/fbtft/fbtft-core.c
+++ b/drivers/staging/fbtft/fbtft-core.c
@@ -365,9 +365,14 @@ static int fbtft_fb_setcolreg(unsigned int regno, unsigned int red,
 	unsigned int val;
 	int ret = 1;
 
+#ifdef CONFIG_FB_DEVICE
 	dev_dbg(info->dev,
 		"%s(regno=%u, red=0x%X, green=0x%X, blue=0x%X, trans=0x%X)\n",
 		__func__, regno, red, green, blue, transp);
+#else
+	pr_debug("%s(regno=%u, red=0x%X, green=0x%X, blue=0x%X, trans=0x%X)\n",
+		 __func__, regno, red, green, blue, transp);
+#endif
 
 	switch (info->fix.visual) {
 	case FB_VISUAL_TRUECOLOR:
@@ -391,8 +396,11 @@ static int fbtft_fb_blank(int blank, struct fb_info *info)
 	struct fbtft_par *par = info->par;
 	int ret = -EINVAL;
 
-	dev_dbg(info->dev, "%s(blank=%d)\n",
-		__func__, blank);
+#ifdef CONFIG_FB_DEVICE
+	dev_dbg(info->dev, "%s(blank=%d)\n", __func__, blank);
+#else
+	pr_debug("%s(blank=%d)\n", __func__, blank);
+#endif
 
 	if (!par->fbtftops.blank)
 		return ret;
@@ -793,6 +801,8 @@ int fbtft_register_framebuffer(struct fb_info *fb_info)
 	if (spi)
 		sprintf(text2, ", spi%d.%d at %d MHz", spi->controller->bus_num,
 			spi_get_chipselect(spi, 0), spi->max_speed_hz / 1000000);
+
+#ifdef CONFIG_FB_DEVICE
 	dev_info(fb_info->dev,
 		 "%s frame buffer, %dx%d, %d KiB video memory%s, fps=%lu%s\n",
 		 fb_info->fix.id, fb_info->var.xres, fb_info->var.yres,
@@ -804,6 +814,12 @@ int fbtft_register_framebuffer(struct fb_info *fb_info)
 		fb_info->bl_dev->props.power = BACKLIGHT_POWER_ON;
 		fb_info->bl_dev->ops->update_status(fb_info->bl_dev);
 	}
+#else
+	pr_info("%s frame buffer, %dx%d, %d KiB video memory%s, fps=%lu%s\n",
+		fb_info->fix.id, fb_info->var.xres, fb_info->var.yres,
+		fb_info->fix.smem_len >> 10, text1,
+		HZ / fb_info->fbdefio->delay, text2);
+#endif
 
 	return 0;
 
diff --git a/drivers/staging/fbtft/fbtft-sysfs.c b/drivers/staging/fbtft/fbtft-sysfs.c
index e45c90a03a90..944f74f592d0 100644
--- a/drivers/staging/fbtft/fbtft-sysfs.c
+++ b/drivers/staging/fbtft/fbtft-sysfs.c
@@ -89,6 +89,7 @@ int fbtft_gamma_parse_str(struct fbtft_par *par, u32 *curves,
 	return ret;
 }
 
+#ifdef CONFIG_FB_DEVICE
 static ssize_t
 sprintf_gamma(struct fbtft_par *par, u32 *curves, char *buf)
 {
@@ -145,6 +146,7 @@ static ssize_t show_gamma_curve(struct device *device,
 static struct device_attribute gamma_device_attrs[] = {
 	__ATTR(gamma, 0660, show_gamma_curve, store_gamma_curve),
 };
+#endif
 
 void fbtft_expand_debug_value(unsigned long *debug)
 {
@@ -173,6 +175,7 @@ void fbtft_expand_debug_value(unsigned long *debug)
 	}
 }
 
+#ifdef CONFIG_FB_DEVICE
 static ssize_t store_debug(struct device *device,
 			   struct device_attribute *attr,
 			   const char *buf, size_t count)
@@ -200,17 +203,22 @@ static ssize_t show_debug(struct device *device,
 
 static struct device_attribute debug_device_attr =
 	__ATTR(debug, 0660, show_debug, store_debug);
+#endif
 
 void fbtft_sysfs_init(struct fbtft_par *par)
 {
+#ifdef CONFIG_FB_DEVICE
 	device_create_file(par->info->dev, &debug_device_attr);
 	if (par->gamma.curves && par->fbtftops.set_gamma)
 		device_create_file(par->info->dev, &gamma_device_attrs[0]);
+#endif
 }
 
 void fbtft_sysfs_exit(struct fbtft_par *par)
 {
+#ifdef CONFIG_FB_DEVICE
 	device_remove_file(par->info->dev, &debug_device_attr);
 	if (par->gamma.curves && par->fbtftops.set_gamma)
 		device_remove_file(par->info->dev, &gamma_device_attrs[0]);
+#endif
 }
-- 
2.43.0