ARM: OMAP: Fix warnings in N770 build

Fix some warnings in n770_defconfig build:
drivers/mtd/nand/omap-hw.c:390: warning:
'omap_nand_write_byte' defined but not used

tahvo-usb.c, tahvo-user.c and retu-user.c: ignoring return
value of 'xxx', declared with attribute warn_unused_result

Signed-off-by: Dirk Behme <dirk.behme_at_gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

drivers/cbus/retu-user.c

@@ -272,6 +272,7 @@ static int retu_ioctl(struct inode *inode, struct file *filp,
 		      unsigned int cmd, unsigned long arg)
 {
 	struct retu_tahvo_write_parms par;
+	int ret;
 
 	switch (cmd) {
 	case URT_IOCT_IRQ_SUBSCR:
@@ -279,9 +280,13 @@ static int retu_ioctl(struct inode *inode, struct file *filp,
 	case RETU_IOCH_READ:
 		return retu_user_read_with_mask(arg);
 	case RETU_IOCX_WRITE:
-		copy_from_user(&par, (void __user *) arg, sizeof(par));
+		ret = copy_from_user(&par, (void __user *) arg, sizeof(par));
+		if (ret)
+			printk(KERN_ERR "copy_from_user failed: %d\n", ret);
 		par.result = retu_user_write_with_mask(par.field, par.value);
-		copy_to_user((void __user *) arg, &par, sizeof(par));
+		ret = copy_to_user((void __user *) arg, &par, sizeof(par));
+		if (ret)
+			printk(KERN_ERR "copy_to_user failed: %d\n", ret);
 		break;
 	case RETU_IOCH_ADC_READ:
 		return retu_read_adc(arg);
@@ -326,8 +331,10 @@ static ssize_t retu_read(struct file *filp, char *buf, size_t count,
 		list_move(&irq->node, &retu_irqs_reserve);
 		spin_unlock_irqrestore(&retu_irqs_lock, flags);
 
-		copy_to_user(buf + i * sizeof(irq_id), &irq_id, sizeof(irq_id));
-
+		ret = copy_to_user(buf + i * sizeof(irq_id), &irq_id,
+				   sizeof(irq_id));
+		if (ret)
+			printk(KERN_ERR "copy_to_user failed: %d\n", ret);
 	}
 
 	return count;

drivers/cbus/tahvo-usb.c

@@ -648,10 +648,12 @@ static int tahvo_usb_probe(struct device *dev)
 	}
 
 	/* Attributes */
-	device_create_file(dev, &dev_attr_vbus_state);
+	ret = device_create_file(dev, &dev_attr_vbus_state);
 #ifdef CONFIG_USB_OTG
-	device_create_file(dev, &dev_attr_otg_mode);
+	ret |= device_create_file(dev, &dev_attr_otg_mode);
 #endif
+	if (ret)
+		printk(KERN_ERR "attribute creation failed: %d\n", ret);
 
 	/* Create OTG interface */
 	tahvo_usb_power_off(tu);

drivers/cbus/tahvo-user.c

@@ -256,6 +256,7 @@ static int tahvo_ioctl(struct inode *inode, struct file *filp,
 		       unsigned int cmd, unsigned long arg)
 {
 	struct retu_tahvo_write_parms par;
+	int ret;
 
 	switch (cmd) {
 	case URT_IOCT_IRQ_SUBSCR:
@@ -263,9 +264,13 @@ static int tahvo_ioctl(struct inode *inode, struct file *filp,
 	case TAHVO_IOCH_READ:
 		return tahvo_user_read_with_mask(arg);
 	case TAHVO_IOCX_WRITE:
-		copy_from_user(&par, (void __user *) arg, sizeof(par));
+		ret = copy_from_user(&par, (void __user *) arg, sizeof(par));
+		if (ret)
+			printk(KERN_ERR "copy_from_user failed: %d\n", ret);
 		par.result = tahvo_user_write_with_mask(par.field, par.value);
-		copy_to_user((void __user *) arg, &par, sizeof(par));
+		ret = copy_to_user((void __user *) arg, &par, sizeof(par));
+		if (ret)
+			printk(KERN_ERR "copy_to_user failed: %d\n", ret);
 		break;
 	default:
 		return -ENOIOCTLCMD;
@@ -308,7 +313,10 @@ static ssize_t tahvo_read(struct file *filp, char *buf, size_t count,
 		list_move(&irq->node, &tahvo_irqs_reserve);
 		spin_unlock_irqrestore(&tahvo_irqs_lock, flags);
 
-		copy_to_user(buf + i * sizeof(irq_id), &irq_id, sizeof(irq_id));
+		ret = copy_to_user(buf + i * sizeof(irq_id), &irq_id,
+                                  sizeof(irq_id));
+		if (ret)
+			printk(KERN_ERR "copy_to_user failed: %d\n", ret);
 	}
 
 	return count;

drivers/mtd/nand/omap-hw.c

@@ -386,11 +386,6 @@ static u_char omap_nand_read_byte(struct mtd_info *mtd)
 	return nand_read_reg8(NND_ACCESS);
 }
 
-static void omap_nand_write_byte(struct mtd_info *mtd, u_char byte)
-{
-	nand_write_reg8(NND_ACCESS, byte);
-}
-
 static int omap_nand_dev_ready(struct mtd_info *mtd)
 {
 	u32 l;