staging: gdm72xx: Replace timeval with ktime_t

struct sdu_stamp in the gdm_sdio.h is a timeval type.
'struct timeval now' is used for calculating elapsed time.

32-bit systems using 'struct timeval' will break in the year 2038,
so we have to replace that code with more appropriate types.
This patch changes the gdm72xx driver to use ktime_t.

ktime_get() is better than using do_gettimeofday(),
because it uses the monotonic clock. ktime_sub
are used to subtract two ktime variables.

Build tested this by saying Y to WIMAX_GDM72XX.

Signed-off-by: Tapasweni Pathak <[e-mail]>
Reviewed-by: Arnd Bergmann <[e-mail]>
Signed-off-by: Arnd Bergmann <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/staging/gdm72xx/gdm_sdio.c

···
 #define RX_BUF_SIZE	(25*1024)
 
 #define TX_HZ		2000
-#define TX_INTERVAL	(1000000/TX_HZ)
+#define TX_INTERVAL	(NSEC_PER_SEC/TX_HZ)
 
 static struct sdio_tx *alloc_tx_struct(struct tx_cxt *tx)
 {
···
 		put_tx_struct(t->tx_cxt, t);
 	}
 
-	do_gettimeofday(&tx->sdu_stamp);
+	tx->sdu_stamp = ktime_get();
 	spin_unlock_irqrestore(&tx->lock, flags);
 }
 
···
 	struct sdio_func *func = sdev->func;
 	struct tx_cxt *tx = &sdev->tx;
 	struct sdio_tx *t = NULL;
-	struct timeval now, *before;
+	ktime_t now, before;
 	int is_sdu = 0;
 	long diff;
 	unsigned long flags;
···
 		list_del(&t->list);
 		is_sdu = 0;
 	} else if (!tx->stop_sdu_tx && !list_empty(&tx->sdu_list)) {
-		do_gettimeofday(&now);
-		before = &tx->sdu_stamp;
+		now = ktime_get();
+		before = tx->sdu_stamp;
 
-		diff = (now.tv_sec - before->tv_sec) * 1000000 +
-			(now.tv_usec - before->tv_usec);
+		diff = ktime_to_ns(ktime_sub(now, before));
 		if (diff >= 0 && diff < TX_INTERVAL) {
 			schedule_work(&sdev->ws);
 			spin_unlock_irqrestore(&tx->lock, flags);

drivers/staging/gdm72xx/gdm_sdio.h

···
 #define __GDM72XX_GDM_SDIO_H__
 
 #include <linux/types.h>
-#include <linux/time.h>
+#include <linux/ktime.h>
 
 #define MAX_NR_SDU_BUF  64
 
···
 	struct list_head	free_list;
 	struct list_head	sdu_list;
 	struct list_head	hci_list;
-	struct timeval		sdu_stamp;
+	ktime_t			sdu_stamp;
 	u8			*sdu_buf;
 	spinlock_t		lock;
 	int			can_send;