[PATCH v2] Staging: dgnc: dgnc_*.c: Use usleep_range over udelay to improve coalescing processor wakeups

[Shiva Kerdel]

In most cases, usleep_range is better than udelay, as the precise wakeup
from udelay is unnecessary.

usleep_range gives a much better chance of coalescing processor wakeups.

Signed-off-by: Shiva Kerdel <sh...@exdev.nl>
---
Changes for v2:
    - Squashed the two commits to one patch.

 drivers/staging/dgnc/dgnc_cls.c |  6 +++---
 drivers/staging/dgnc/dgnc_neo.c | 10 +++++-----
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/staging/dgnc/dgnc_cls.c b/drivers/staging/dgnc/dgnc_cls.c
index c20ffdd..6607243a 100644
--- a/drivers/staging/dgnc/dgnc_cls.c
+++ b/drivers/staging/dgnc/dgnc_cls.c
@@ -409,7 +409,7 @@ static void cls_assert_modem_signals(struct channel_t *ch)
        writeb(out, &ch->ch_cls_uart->mcr);
 
        /* Give time for the UART to actually drop the signals */
-       udelay(10);
+       usleep_range(10, 20);
 }
 
 static void cls_copy_data_from_queue_to_uart(struct channel_t *ch)
@@ -631,7 +631,7 @@ static void cls_flush_uart_read(struct channel_t *ch)
         * Presumably, this is a bug in this UART.
         */
 
-       udelay(10);
+       usleep_range(10, 20);
 }
 
 /*
@@ -1096,7 +1096,7 @@ static void cls_uart_init(struct channel_t *ch)
 
        writeb(UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT,
               &ch->ch_cls_uart->isr_fcr);
-       udelay(10);
+       usleep_range(10, 20);
 
        ch->ch_flags |= (CH_FIFO_ENABLED | CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
 
diff --git a/drivers/staging/dgnc/dgnc_neo.c b/drivers/staging/dgnc/dgnc_neo.c
index 3eefefe..20bc271 100644
--- a/drivers/staging/dgnc/dgnc_neo.c
+++ b/drivers/staging/dgnc/dgnc_neo.c
@@ -1352,7 +1352,7 @@ static void neo_flush_uart_write(struct channel_t *ch)
                 */
                tmp = readb(&ch->ch_neo_uart->isr_fcr);
                if (tmp & 4)
-                       udelay(10);
+                       usleep_range(10, 20);
                else
                        break;
        }
@@ -1384,7 +1384,7 @@ static void neo_flush_uart_read(struct channel_t *ch)
                 */
                tmp = readb(&ch->ch_neo_uart->isr_fcr);
                if (tmp & 2)
-                       udelay(10);
+                       usleep_range(10, 20);
                else
                        break;
        }
@@ -1616,7 +1616,7 @@ static void neo_assert_modem_signals(struct channel_t *ch)
        neo_pci_posting_flush(ch->ch_bd);
 
        /* Give time for the UART to actually raise/drop the signals */
-       udelay(10);
+       usleep_range(10, 20);
 }
 
 static void neo_send_start_character(struct channel_t *ch)
@@ -1628,7 +1628,7 @@ static void neo_send_start_character(struct channel_t *ch)
                ch->ch_xon_sends++;
                writeb(ch->ch_startc, &ch->ch_neo_uart->txrx);
                neo_pci_posting_flush(ch->ch_bd);
-               udelay(10);
+               usleep_range(10, 20);
        }
 }
 
@@ -1641,7 +1641,7 @@ static void neo_send_stop_character(struct channel_t *ch)
                ch->ch_xoff_sends++;
                writeb(ch->ch_stopc, &ch->ch_neo_uart->txrx);
                neo_pci_posting_flush(ch->ch_bd);
-               udelay(10);
+               usleep_range(10, 20);
        }
 }
 
-- 
2.10.2