[U-Boot] [PATCH 1/2] i2c: Fix deselection of muxes

Mark Tomlinson mark.tomlinson at alliedtelesis.co.nz
Mon Dec 1 20:49:18 CET 2014


Due to an uninitialised variable, when muxes were deselected, any value
could be written to the mux control register. On the PCA9548, this could
result in multiple channels being selected, thus enabling multiple
pull-up resistors, and much bus capacitance.

The fix is simply to initialise the written value to zero.

Signed-off-by: Mark Tomlinson <mark.tomlinson at alliedtelesis.co.nz>
---
 drivers/i2c/i2c_core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/i2c/i2c_core.c b/drivers/i2c/i2c_core.c
index d34b749..4539667 100644
--- a/drivers/i2c/i2c_core.c
+++ b/drivers/i2c/i2c_core.c
@@ -178,7 +178,7 @@ static int i2c_mux_disconnet_all(void)
 {
 	struct	i2c_bus_hose *i2c_bus_tmp = &i2c_bus[I2C_BUS];
 	int	i;
-	uint8_t	buf;
+	uint8_t	buf = 0;
 
 	if (I2C_ADAP->init_done == 0)
 		return 0;
-- 
1.9.1



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