[PATCH] serial: efm32: Fix parity management in 'efm32_uart_console_get_options()'

Subsystems: the rest, tty layer and serial drivers

STALE3511d

2 messages, 2 authors, 2017-02-11 · open the first message on its own page

[PATCH] serial: efm32: Fix parity management in 'efm32_uart_console_get_options()'

From: Christophe JAILLET <hidden>
Date: 2017-02-10 21:06:53

UARTn_FRAME_PARITY_ODD is 0x0300
UARTn_FRAME_PARITY_EVEN is 0x0200
So if the UART is configured for EVEN parity, it would be reported as ODD.
Fix it by testing if the 2 bits are set in the ODD case.

Signed-off-by: Christophe JAILLET <redacted>
---
Un-tested
---
 drivers/tty/serial/efm32-uart.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/serial/efm32-uart.c b/drivers/tty/serial/efm32-uart.c
index ebd8569f9ad5..84034ef20c88 100644
--- a/drivers/tty/serial/efm32-uart.c
+++ b/drivers/tty/serial/efm32-uart.c
@@ -572,9 +572,9 @@ static void efm32_uart_console_get_options(struct efm32_uart_port *efm_port,
 			16 * (4 + (clkdiv >> 6)));
 
 	frame = efm32_uart_read32(efm_port, UARTn_FRAME);
-	if (frame & UARTn_FRAME_PARITY_ODD)
+	if ((frame & UARTn_FRAME_PARITY_ODD) == UARTn_FRAME_PARITY_ODD)
 		*parity = 'o';
-	else if (frame & UARTn_FRAME_PARITY_EVEN)
+	else if ((frame & UARTn_FRAME_PARITY_EVEN) == UARTn_FRAME_PARITY_EVEN)
 		*parity = 'e';
 	else
 		*parity = 'n';
-- 
2.9.3

Re: [PATCH] serial: efm32: Fix parity management in 'efm32_uart_console_get_options()'

From: Uwe Kleine-König <hidden>
Date: 2017-02-11 18:30:31

On Fri, Feb 10, 2017 at 10:06:40PM +0100, Christophe JAILLET wrote:
quoted hunk
UARTn_FRAME_PARITY_ODD is 0x0300
UARTn_FRAME_PARITY_EVEN is 0x0200
So if the UART is configured for EVEN parity, it would be reported as ODD.
Fix it by testing if the 2 bits are set in the ODD case.

Signed-off-by: Christophe JAILLET <redacted>
---
Un-tested
---
 drivers/tty/serial/efm32-uart.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/serial/efm32-uart.c b/drivers/tty/serial/efm32-uart.c
index ebd8569f9ad5..84034ef20c88 100644
--- a/drivers/tty/serial/efm32-uart.c
+++ b/drivers/tty/serial/efm32-uart.c
@@ -572,9 +572,9 @@ static void efm32_uart_console_get_options(struct efm32_uart_port *efm_port,
 			16 * (4 + (clkdiv >> 6)));
 
 	frame = efm32_uart_read32(efm_port, UARTn_FRAME);
-	if (frame & UARTn_FRAME_PARITY_ODD)
+	if ((frame & UARTn_FRAME_PARITY_ODD) == UARTn_FRAME_PARITY_ODD)
 		*parity = 'o';
-	else if (frame & UARTn_FRAME_PARITY_EVEN)
+	else if ((frame & UARTn_FRAME_PARITY_EVEN) == UARTn_FRAME_PARITY_EVEN)
There is really a bug, but the fix looks wrong (although it does the
right thing). The check for UARTn_FRAME_PARITY_EVEN should check both
bits, too.

The right change that works independent of the actual
values would be:
diff --git a/drivers/tty/serial/efm32-uart.c b/drivers/tty/serial/efm32-uart.c
index 195acc868763..00cdffbe4eda 100644
--- a/drivers/tty/serial/efm32-uart.c
+++ b/drivers/tty/serial/efm32-uart.c
@@ -27,6 +27,7 @@
 #define UARTn_FRAME		0x04
 #define UARTn_FRAME_DATABITS__MASK	0x000f
 #define UARTn_FRAME_DATABITS(n)		((n) - 3)
+#define UARTn_FRAME_PARITY		0x0300
 #define UARTn_FRAME_PARITY_NONE		0x0000
 #define UARTn_FRAME_PARITY_EVEN		0x0200
 #define UARTn_FRAME_PARITY_ODD		0x0300
@@ -572,12 +573,16 @@ static void efm32_uart_console_get_options(struct efm32_uart_port *efm_port,
 			16 * (4 + (clkdiv >> 6)));
 
 	frame = efm32_uart_read32(efm_port, UARTn_FRAME);
-	if (frame & UARTn_FRAME_PARITY_ODD)
+	switch (frame & UARTn_FRAME_PARITY) {
+	case UARTn_FRAME_PARITY_ODD:
 		*parity = 'o';
-	else if (frame & UARTn_FRAME_PARITY_EVEN)
+		break;
+	case UARTn_FRAME_PARITY_EVEN:
 		*parity = 'e';
-	else
+		break;
+	default:
 		*parity = 'n';
+	}
 
 	*bits = (frame & UARTn_FRAME_DATABITS__MASK) -
 			UARTn_FRAME_DATABITS(4) + 4;

I'd suggest to add

Fixes: 3afbd89c9639 ("serial/efm32: add new driver")

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-K?nig            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
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