arm/komeda: Convert dp_wait_cond() to return an error code.

dp_wait_cond() currently returns the number of retries left over which
is hardly an useful information. Convert to returning -ETIMEDOUT when
the wait times out, or 0 (zero) when condition is met before deadline.

Also convert the users of the function to return the error value.
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>
Reviewed-by: James Qian Wang (Arm Technology China) <james.qian.wang@arm.com>

drivers/gpu/drm/arm/display/include/malidp_utils.h

@@ -8,6 +8,7 @@
 #define _MALIDP_UTILS_
 
 #include <linux/delay.h>
+#include <linux/errno.h>
 
 #define has_bit(nr, mask)	(BIT(nr) & (mask))
 #define has_bits(bits, mask)	(((bits) & (mask)) == (bits))
@@ -20,11 +21,9 @@
 	int num_tries = __tries;			\
 	while (!__cond && (num_tries > 0)) {		\
 		usleep_range(__min_range, __max_range);	\
-		if (__cond)				\
-			break;				\
 		num_tries--;				\
 	}						\
-	num_tries;					\
+	(__cond) ? 0 : -ETIMEDOUT;			\
 })
 
 /* the restriction of range is [start, end] */

drivers/gpu/drm/arm/display/komeda/d71/d71_dev.c

@@ -280,7 +280,7 @@ static int d71_change_opmode(struct komeda_dev *mdev, int new_mode)
 	ret = dp_wait_cond(((malidp_read32(d71->gcu_addr, BLK_CONTROL) & 0x7) == opmode),
 			   100, 1000, 10000);
 
-	return ret > 0 ? 0 : -ETIMEDOUT;
+	return ret;
 }
 
 static void d71_flush(struct komeda_dev *mdev,
@@ -304,7 +304,7 @@ static int d71_reset(struct d71_dev *d71)
 	ret = dp_wait_cond(!(malidp_read32(gcu, BLK_CONTROL) & GCU_CONTROL_SRST),
 			   100, 1000, 10000);
 
-	return ret > 0 ? 0 : -ETIMEDOUT;
+	return ret;
 }
 
 void d71_read_block_header(u32 __iomem *reg, struct block_header *blk)