drivers/video: fsl-diu-fb: only DIU modes 0 and 1 are supported

The Freescale DIU video controller supports five video "modes", but only
the first two are used by the driver. The other three are special modes
that don't make sense for a framebuffer driver. Therefore, there's no
point in keeping a global variable that indicates which mode we're
supposed to use.

Signed-off-by: Timur Tabi <[e-mail]>
Signed-off-by: Florian Tobias Schandinat <[e-mail]>

arch/powerpc/platforms/512x/mpc512x_shared.c

···
 	}
 
 	mode = in_be32(&diu_reg->diu_mode);
-	if (mode != MFB_MODE1) {
+	if (mode == MFB_MODE0) {
 		pr_info("%s: DIU OFF\n", __func__);
 		goto out;
 	}

drivers/video/fsl-diu-fb.c

···
 struct diu_hw {
 	struct diu __iomem *diu_reg;
 	spinlock_t reg_lock;
-	unsigned int mode;		/* DIU operation mode */
 };
 
 struct diu_addr {
···
 };
 
 static struct diu_hw dr = {
-	.mode = MFB_MODE1,
 	.reg_lock = __SPIN_LOCK_UNLOCKED(diu_hw.reg_lock),
 };
 
···
 	struct fsl_diu_data *machine_data = mfbi->parent;
 
 	if (!machine_data->fb_enabled) {
-		out_be32(&hw->diu_mode, dr.mode);
+		out_be32(&hw->diu_mode, MFB_MODE1);
 		machine_data->fb_enabled++;
 	}
 }
···
 		ints |=	INT_VSYNC;
 #endif
 
-		if (dr.mode == MFB_MODE2 || dr.mode == MFB_MODE3)
-			ints |= INT_VSYNC_WB;
-
 		/* Read to clear the status */
 		in_be32(&hw->int_status);
 		out_be32(&hw->int_mask, ints);
···
 	}
 
 	diu_mode = in_be32(&dr.diu_reg->diu_mode);
-	if (diu_mode != MFB_MODE1)
+	if (diu_mode == MFB_MODE0)
 		out_be32(&dr.diu_reg->diu_mode, 0);	/* disable DIU */
 
 	/* Get the IRQ of the DIU */
···
 	 * Let DIU display splash screen if it was pre-initialized
 	 * by the bootloader, set dummy area descriptor otherwise.
 	 */
-	if (diu_mode != MFB_MODE1)
+	if (diu_mode == MFB_MODE0)
 		out_be32(&dr.diu_reg->desc[0], machine_data->dummy_ad->paddr);
 
 	out_be32(&dr.diu_reg->desc[1], machine_data->dummy_ad->paddr);

include/linux/fsl-diu-fb.h

···
 	__be32 plut;
 } __attribute__ ((packed));
 
-/* Modes of operation of DIU */
+/*
+ * Modes of operation of DIU.  The DIU supports five different modes, but
+ * the driver only supports modes 0 and 1.
+ */
 #define MFB_MODE0	0	/* DIU off */
 #define MFB_MODE1	1	/* All three planes output to display */
-#define MFB_MODE2	2	/* Plane 1 to display, planes 2+3 written back*/
-#define MFB_MODE3	3	/* All three planes written back to memory */
-#define MFB_MODE4	4	/* Color bar generation */
 
 #endif /* __KERNEL__ */
 #endif /* __FSL_DIU_FB_H__ */