Revert "Staging: panel: usleep_range is preferred over udelay"

This reverts commit ebd4351.

We should not be sleeping inside spin_lock.

Fixes: ebd4351 ("Staging: panel: usleep_range is preferred over udelay")
Cc: Sirnam Swetha <theonly.ultimate@gmail.com>
Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
Reported-by: Huang, Ying <ying.huang@intel.com>
Tested-by: Huang, Ying <ying.huang@intel.com>
Cc: stable <stable@vger.kernel.org> # 4.4
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: sudipm-mukherjee

drivers/staging/panel/panel.c

@@ -825,8 +825,7 @@ static void lcd_write_cmd_s(int cmd)
 	lcd_send_serial(0x1F);	/* R/W=W, RS=0 */
 	lcd_send_serial(cmd & 0x0F);
 	lcd_send_serial((cmd >> 4) & 0x0F);
-	/* the shortest command takes at least 40 us */
-	usleep_range(40, 100);
+	udelay(40);		/* the shortest command takes at least 40 us */
 	spin_unlock_irq(&pprt_lock);
 }
 
@@ -837,8 +836,7 @@ static void lcd_write_data_s(int data)
 	lcd_send_serial(0x5F);	/* R/W=W, RS=1 */
 	lcd_send_serial(data & 0x0F);
 	lcd_send_serial((data >> 4) & 0x0F);
-	/* the shortest data takes at least 40 us */
-	usleep_range(40, 100);
+	udelay(40);		/* the shortest data takes at least 40 us */
 	spin_unlock_irq(&pprt_lock);
 }
 
@@ -848,20 +846,19 @@ static void lcd_write_cmd_p8(int cmd)
 	spin_lock_irq(&pprt_lock);
 	/* present the data to the data port */
 	w_dtr(pprt, cmd);
-	/* maintain the data during 20 us before the strobe */
-	usleep_range(20, 100);
+	udelay(20);	/* maintain the data during 20 us before the strobe */
 
 	bits.e = BIT_SET;
 	bits.rs = BIT_CLR;
 	bits.rw = BIT_CLR;
 	set_ctrl_bits();
 
-	usleep_range(40, 100);	/* maintain the strobe during 40 us */
+	udelay(40);	/* maintain the strobe during 40 us */
 
 	bits.e = BIT_CLR;
 	set_ctrl_bits();
 
-	usleep_range(120, 500);	/* the shortest command takes at least 120 us */
+	udelay(120);	/* the shortest command takes at least 120 us */
 	spin_unlock_irq(&pprt_lock);
 }
 
@@ -871,20 +868,19 @@ static void lcd_write_data_p8(int data)
 	spin_lock_irq(&pprt_lock);
 	/* present the data to the data port */
 	w_dtr(pprt, data);
-	/* maintain the data during 20 us before the strobe */
-	usleep_range(20, 100);
+	udelay(20);	/* maintain the data during 20 us before the strobe */
 
 	bits.e = BIT_SET;
 	bits.rs = BIT_SET;
 	bits.rw = BIT_CLR;
 	set_ctrl_bits();
 
-	usleep_range(40, 100);	/* maintain the strobe during 40 us */
+	udelay(40);	/* maintain the strobe during 40 us */
 
 	bits.e = BIT_CLR;
 	set_ctrl_bits();
 
-	usleep_range(45, 100);	/* the shortest data takes at least 45 us */
+	udelay(45);	/* the shortest data takes at least 45 us */
 	spin_unlock_irq(&pprt_lock);
 }
 
@@ -894,7 +890,7 @@ static void lcd_write_cmd_tilcd(int cmd)
 	spin_lock_irq(&pprt_lock);
 	/* present the data to the control port */
 	w_ctr(pprt, cmd);
-	usleep_range(60, 120);
+	udelay(60);
 	spin_unlock_irq(&pprt_lock);
 }
 
@@ -904,7 +900,7 @@ static void lcd_write_data_tilcd(int data)
 	spin_lock_irq(&pprt_lock);
 	/* present the data to the data port */
 	w_dtr(pprt, data);
-	usleep_range(60, 120);
+	udelay(60);
 	spin_unlock_irq(&pprt_lock);
 }
 
@@ -947,7 +943,7 @@ static void lcd_clear_fast_s(void)
 		lcd_send_serial(0x5F);	/* R/W=W, RS=1 */
 		lcd_send_serial(' ' & 0x0F);
 		lcd_send_serial((' ' >> 4) & 0x0F);
-		usleep_range(40, 100);	/* the shortest data takes at least 40 us */
+		udelay(40);	/* the shortest data takes at least 40 us */
 	}
 	spin_unlock_irq(&pprt_lock);
 
@@ -971,21 +967,21 @@ static void lcd_clear_fast_p8(void)
 		w_dtr(pprt, ' ');
 
 		/* maintain the data during 20 us before the strobe */
-		usleep_range(20, 100);
+		udelay(20);
 
 		bits.e = BIT_SET;
 		bits.rs = BIT_SET;
 		bits.rw = BIT_CLR;
 		set_ctrl_bits();
 
 		/* maintain the strobe during 40 us */
-		usleep_range(40, 100);
+		udelay(40);
 
 		bits.e = BIT_CLR;
 		set_ctrl_bits();
 
 		/* the shortest data takes at least 45 us */
-		usleep_range(45, 100);
+		udelay(45);
 	}
 	spin_unlock_irq(&pprt_lock);
 
@@ -1007,7 +1003,7 @@ static void lcd_clear_fast_tilcd(void)
 	for (pos = 0; pos < lcd.height * lcd.hwidth; pos++) {
 		/* present the data to the data port */
 		w_dtr(pprt, ' ');
-		usleep_range(60, 120);
+		udelay(60);
 	}
 
 	spin_unlock_irq(&pprt_lock);