Before reset dbgu transmitter, we just wait TXEMPTY to drain the
transmitter register. If not doing this, we may sometimes see several
weird characters from DBGU.
A short delay is also added to make sure the new serial settings are
settled.
Signed-off-by: Hong Xu <hong...@atmel.com>
---
drivers/serial/atmel_usart.c | 8 +++++++-
1 files changed, 7 insertions(+), 1 deletions(-)
diff --git a/drivers/serial/atmel_usart.c b/drivers/serial/atmel_usart.c
index e326b2b..0d5d254 100644
--- a/drivers/serial/atmel_usart.c
+++ b/drivers/serial/atmel_usart.c
@@ -49,17 +49,23 @@ int serial_init(void)
{
atmel_usart3_t *usart = (atmel_usart3_t *)CONFIG_USART_BASE;
+ /* Just in case: drain transmitter register */
+ while (!(readl(&usart->csr) & USART3_BIT(TXEMPTY)))
+ ;
+
writel(USART3_BIT(RSTRX) | USART3_BIT(RSTTX), &usart->cr);
serial_setbrg();
- writel(USART3_BIT(RXEN) | USART3_BIT(TXEN), &usart->cr);
writel((USART3_BF(USART_MODE, USART3_USART_MODE_NORMAL)
| USART3_BF(USCLKS, USART3_USCLKS_MCK)
| USART3_BF(CHRL, USART3_CHRL_8)
| USART3_BF(PAR, USART3_PAR_NONE)
| USART3_BF(NBSTOP, USART3_NBSTOP_1)),
&usart->mr);
+ writel(USART3_BIT(RXEN) | USART3_BIT(TXEN), &usart->cr);
+ /* __udelay(100) is enough for the new settings to be settled */
+ __udelay(100);
return 0;
}
--
1.7.3.3
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