drivers/video/pmag-ba-fb.c: improve diagnostics

Add error messages to the probe call.

While they may rarely trigger, they may be useful when something weird is
going on. Also this is good style.

[[e-mail]: remove unneeded initialisation]
Signed-off-by: Maciej W. Rozycki <[e-mail]>
Cc: Mariusz Kozlowski <[e-mail]>
Cc: Ralf Baechle <[e-mail]>
Cc: "Antonino A. Daplas" <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/video/pmag-ba-fb.c

···
 	resource_size_t start, len;
 	struct fb_info *info;
 	struct pmagbafb_par *par;
+	int err;
 
 	info = framebuffer_alloc(sizeof(struct pmagbafb_par), dev);
-	if (!info)
+	if (!info) {
+		printk(KERN_ERR "%s: Cannot allocate memory\n", dev->bus_id);
 		return -ENOMEM;
+	}
 
 	par = info->par;
 	dev_set_drvdata(dev, info);
 
-	if (fb_alloc_cmap(&info->cmap, 256, 0) < 0)
+	if (fb_alloc_cmap(&info->cmap, 256, 0) < 0) {
+		printk(KERN_ERR "%s: Cannot allocate color map\n",
+		       dev->bus_id);
+		err = -ENOMEM;
 		goto err_alloc;
+	}
 
 	info->fbops = &pmagbafb_ops;
 	info->fix = pmagbafb_fix;
···
 	/* Request the I/O MEM resource.  */
 	start = tdev->resource.start;
 	len = tdev->resource.end - start + 1;
-	if (!request_mem_region(start, len, dev->bus_id))
+	if (!request_mem_region(start, len, dev->bus_id)) {
+		printk(KERN_ERR "%s: Cannot reserve FB region\n", dev->bus_id);
+		err = -EBUSY;
 		goto err_cmap;
+	}
 
 	/* MMIO mapping setup.  */
 	info->fix.mmio_start = start;
 	par->mmio = ioremap_nocache(info->fix.mmio_start, info->fix.mmio_len);
-	if (!par->mmio)
+	if (!par->mmio) {
+		printk(KERN_ERR "%s: Cannot map MMIO\n", dev->bus_id);
+		err = -ENOMEM;
 		goto err_resource;
+	}
 	par->dac = par->mmio + PMAG_BA_BT459;
 
 	/* Frame buffer mapping setup.  */
 	info->fix.smem_start = start + PMAG_BA_FBMEM;
 	info->screen_base = ioremap_nocache(info->fix.smem_start,
 					    info->fix.smem_len);
-	if (!info->screen_base)
+	if (!info->screen_base) {
+		printk(KERN_ERR "%s: Cannot map FB\n", dev->bus_id);
+		err = -ENOMEM;
 		goto err_mmio_map;
+	}
 	info->screen_size = info->fix.smem_len;
 
 	pmagbafb_erase_cursor(info);
 
-	if (register_framebuffer(info) < 0)
+	err = register_framebuffer(info);
+	if (err < 0) {
+		printk(KERN_ERR "%s: Cannot register framebuffer\n",
+		       dev->bus_id);
 		goto err_smem_map;
+	}
 
 	get_device(dev);
 
···
 
 err_alloc:
 	framebuffer_release(info);
-	return -ENXIO;
+	return err;
 }
 
 static int __exit pmagbafb_remove(struct device *dev)