[E1000-devel] [PATCH v2 1/3] Do not drive on scl or sda when reading

[Jean-Hugues Deschenes]

This patch ensures that output drivers are off prior to sampling data from the
scl and sda lines on the i2c bus.

Signed-off-by: Jean-Hugues Deschenes <jean-hugues.desche...@octasic.com>
Index: igb-5.2.9.4-ori/src/igb_main.c
===================================================================
--- igb-5.2.9.4-ori.orig/src/igb_main.c 2014-08-04 18:19:04.000000000 -0400
+++ igb-5.2.9.4-ori/src/igb_main.c      2014-11-26 13:16:44.360050188 -0500
@@ -1634,6 +1634,13 @@
        struct e1000_hw *hw = &adapter->hw;
        s32 i2cctl = E1000_READ_REG(hw, E1000_I2CPARAMS);
 
+       i2cctl |= E1000_I2C_DATA_OE_N;
+
+       E1000_WRITE_REG(hw, E1000_I2CPARAMS, i2cctl);
+       E1000_WRITE_FLUSH(hw);
+
+       i2cctl = E1000_READ_REG(hw, E1000_I2CPARAMS);
+
        return !!(i2cctl & E1000_I2C_DATA_IN);
 }
 
@@ -1696,6 +1703,13 @@
        struct e1000_hw *hw = &adapter->hw;
        s32 i2cctl = E1000_READ_REG(hw, E1000_I2CPARAMS);
 
+       i2cctl |= E1000_I2C_CLK_OE_N;
+
+       E1000_WRITE_REG(hw, E1000_I2CPARAMS, i2cctl);
+       E1000_WRITE_FLUSH(hw);
+
+       i2cctl = E1000_READ_REG(hw, E1000_I2CPARAMS);
+
        return !!(i2cctl & E1000_I2C_CLK_IN);
 }
 


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