staging: fbtft: Fix build failure when CONFIG_FB_DEVICE=n

When CONFIG_FB_DEVICE is disabled, struct fb_info does
not provide a valid dev pointer. Direct dereferences of
fb_info->dev therefore result in build failures.

Fix this by avoiding direct accesses to fb_info->dev and
switching the affected debug logging to framebuffer helpers
that do not rely on a device pointer.

This fixes the following build failure reported by the
kernel test robot.

Fixes: a06d03f ("staging: fbtft: Make FB_DEVICE dependency optional")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202601110740.Y9XK5HtN-lkp@intel.com
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Chintan Patel <chintanlike@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>

Author: nehudesi

drivers/staging/fbtft/fbtft-core.c

@@ -365,9 +365,9 @@ static int fbtft_fb_setcolreg(unsigned int regno, unsigned int red,
 	unsigned int val;
 	int ret = 1;
 
-	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);
+	fb_dbg(info,
+	       "regno=%u, red=0x%X, green=0x%X, blue=0x%X, trans=0x%X\n",
+	       regno, red, green, blue, transp);
 
 	switch (info->fix.visual) {
 	case FB_VISUAL_TRUECOLOR:
@@ -391,8 +391,7 @@ 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);
+	fb_dbg(info, "blank=%d\n", blank);
 
 	if (!par->fbtftops.blank)
 		return ret;
@@ -793,11 +792,11 @@ 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);
-	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,
-		 fb_info->fix.smem_len >> 10, text1,
-		 HZ / fb_info->fbdefio->delay, text2);
+	fb_info(fb_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);
 
 	/* Turn on backlight if available */
 	if (fb_info->bl_dev) {