[PATCH v8 1/2] staging: fbtft: Fix build failure when CONFIG_FB_DEVICE=n

[Chintan Patel <chintanlike@gmail.com>]

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: a06d03f9f238 ("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>

---
Changes in v8:
- Add Reviewed-by tag from Andy Shevchenko.

Changes in v7:
- Split logging cleanups into a separate patch
- Limit this patch to the CONFIG_FB_DEVICE=n build fix only

Changes in v6:
- Switch debug/info logging to fb_dbg() and fb_info()(suggested by Thomas Zimmermann)
- Drop dev_of_fbinfo() usage in favor of framebuffer helpers that implicitly
  handle the debug/info context.
- Drop __func__ usage per review feedback(suggested by greg k-h)
- Add Fixes tag for a06d03f9f238 ("staging: fbtft: Make FB_DEVICE dependency optional")
  (suggested by Andy Shevchenko)

Changes in v5:
- Initial attempt to replace info->dev accesses using
  dev_of_fbinfo() helper

 drivers/staging/fbtft/fbtft-core.c | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/drivers/staging/fbtft/fbtft-core.c b/drivers/staging/fbtft/fbtft-core.c
index 8a5ccc8ae0a1..1b3b62950205 100644
--- a/drivers/staging/fbtft/fbtft-core.c
+++ b/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) {
-- 
2.43.0