can: mcp251x: read-modify-write eflag only when needed

Use read-modify-write instead of a simple write to change the register
contents, to close existing the race window between the original manual
read and write.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Acked-by: Wolfgang Grandegger <wg@grandegger.com>
This commit is contained in:
Sascha Hauer 2010-09-28 10:00:47 +02:00 committed by Marc Kleine-Budde
parent f3a3ed3115
commit 7e15de3a73

View file

@ -785,7 +785,8 @@ static irqreturn_t mcp251x_can_ist(int irq, void *dev_id)
mcp251x_write_bits(spi, CANINTF, intf, 0x00);
mcp251x_write_reg(spi, EFLG, 0x00);
if (eflag)
mcp251x_write_bits(spi, EFLG, eflag, 0x00);
/* Update can state */
if (eflag & EFLG_TXBO) {