[PATCH 4.4 269/342] Revert "Staging: panel: usleep_range is preferred over udelay"

From: Greg Kroah-Hartman
Date: Tue Mar 01 2016 - 19:22:59 EST


4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Sudip Mukherjee <sudipm.mukherjee@xxxxxxxxx>

commit b64a1cbef6df47c986ad622b5b2e4d3d1940070c upstream.

This reverts commit ebd43516d3879f882a403836bba8bc5791f26a28.

We should not be sleeping inside spin_lock.

Fixes: ebd43516d387 ("Staging: panel: usleep_range is preferred over udelay")
Cc: Sirnam Swetha <theonly.ultimate@xxxxxxxxx>
Signed-off-by: Sudip Mukherjee <sudip@xxxxxxxxxxxxxxx>
Reported-by: Huang, Ying <ying.huang@xxxxxxxxx>
Tested-by: Huang, Ying <ying.huang@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

diff --git a/drivers/staging/panel/panel.c b/drivers/staging/panel/panel.c
index 79ac19246548..70b8f4fabfad 100644
--- a/drivers/staging/panel/panel.c
+++ b/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);

@@ -971,7 +967,7 @@ 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;
@@ -979,13 +975,13 @@ static void lcd_clear_fast_p8(void)
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);