ixgbe: Enable bit-banging mode on X550

Set the bit banging mode in the hardware when performing bit banging
I2C operations on X550. Also control the output enable on both the
clock and data lines.
Signed-off-by: Mark Rustad <mark.d.rustad@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c

@@ -1952,11 +1952,14 @@ s32 ixgbe_write_i2c_byte_generic_unlocked(struct ixgbe_hw *hw, u8 byte_offset,
  *  @hw: pointer to hardware structure
  *
  *  Sets I2C start condition (High -> Low on SDA while SCL is High)
+ *  Set bit-bang mode on X550 hardware.
  **/
 static void ixgbe_i2c_start(struct ixgbe_hw *hw)
 {
 	u32 i2cctl = IXGBE_READ_REG(hw, IXGBE_I2CCTL(hw));
 
+	i2cctl |= IXGBE_I2C_BB_EN(hw);
+
 	/* Start condition must begin with data and clock high */
 	ixgbe_set_i2c_data(hw, &i2cctl, 1);
 	ixgbe_raise_i2c_clk(hw, &i2cctl);
@@ -1981,10 +1984,15 @@ static void ixgbe_i2c_start(struct ixgbe_hw *hw)
  *  @hw: pointer to hardware structure
  *
  *  Sets I2C stop condition (Low -> High on SDA while SCL is High)
+ *  Disables bit-bang mode and negates data output enable on X550
+ *  hardware.
  **/
 static void ixgbe_i2c_stop(struct ixgbe_hw *hw)
 {
 	u32 i2cctl = IXGBE_READ_REG(hw, IXGBE_I2CCTL(hw));
+	u32 data_oe_bit = IXGBE_I2C_DATA_OE_N_EN(hw);
+	u32 clk_oe_bit = IXGBE_I2C_CLK_OE_N_EN(hw);
+	u32 bb_en_bit = IXGBE_I2C_BB_EN(hw);
 
 	/* Stop condition must begin with data low and clock high */
 	ixgbe_set_i2c_data(hw, &i2cctl, 0);
@@ -1997,6 +2005,13 @@ static void ixgbe_i2c_stop(struct ixgbe_hw *hw)
 
 	/* bus free time between stop and start (4.7us)*/
 	udelay(IXGBE_I2C_T_BUF);
+
+	if (bb_en_bit || data_oe_bit || clk_oe_bit) {
+		i2cctl &= ~bb_en_bit;
+		i2cctl |= data_oe_bit | clk_oe_bit;
+		IXGBE_WRITE_REG(hw, IXGBE_I2CCTL(hw), i2cctl);
+		IXGBE_WRITE_FLUSH(hw);
+	}
 }
 
 /**
@@ -2044,6 +2059,7 @@ static s32 ixgbe_clock_out_i2c_byte(struct ixgbe_hw *hw, u8 data)
 	/* Release SDA line (set high) */
 	i2cctl = IXGBE_READ_REG(hw, IXGBE_I2CCTL(hw));
 	i2cctl |= IXGBE_I2C_DATA_OUT(hw);
+	i2cctl |= IXGBE_I2C_DATA_OE_N_EN(hw);
 	IXGBE_WRITE_REG(hw, IXGBE_I2CCTL(hw), i2cctl);
 	IXGBE_WRITE_FLUSH(hw);
 
@@ -2058,15 +2074,21 @@ static s32 ixgbe_clock_out_i2c_byte(struct ixgbe_hw *hw, u8 data)
  **/
 static s32 ixgbe_get_i2c_ack(struct ixgbe_hw *hw)
 {
+	u32 data_oe_bit = IXGBE_I2C_DATA_OE_N_EN(hw);
 	s32 status = 0;
 	u32 i = 0;
 	u32 i2cctl = IXGBE_READ_REG(hw, IXGBE_I2CCTL(hw));
 	u32 timeout = 10;
 	bool ack = true;
 
+	if (data_oe_bit) {
+		i2cctl |= IXGBE_I2C_DATA_OUT(hw);
+		i2cctl |= data_oe_bit;
+		IXGBE_WRITE_REG(hw, IXGBE_I2CCTL(hw), i2cctl);
+		IXGBE_WRITE_FLUSH(hw);
+	}
 	ixgbe_raise_i2c_clk(hw, &i2cctl);
 
-
 	/* Minimum high period of clock is 4us */
 	udelay(IXGBE_I2C_T_HIGH);
 
@@ -2104,7 +2126,14 @@ static s32 ixgbe_get_i2c_ack(struct ixgbe_hw *hw)
 static s32 ixgbe_clock_in_i2c_bit(struct ixgbe_hw *hw, bool *data)
 {
 	u32 i2cctl = IXGBE_READ_REG(hw, IXGBE_I2CCTL(hw));
+	u32 data_oe_bit = IXGBE_I2C_DATA_OE_N_EN(hw);
 
+	if (data_oe_bit) {
+		i2cctl |= IXGBE_I2C_DATA_OUT(hw);
+		i2cctl |= data_oe_bit;
+		IXGBE_WRITE_REG(hw, IXGBE_I2CCTL(hw), i2cctl);
+		IXGBE_WRITE_FLUSH(hw);
+	}
 	ixgbe_raise_i2c_clk(hw, &i2cctl);
 
 	/* Minimum high period of clock is 4us */
@@ -2159,13 +2188,20 @@ static s32 ixgbe_clock_out_i2c_bit(struct ixgbe_hw *hw, bool data)
  *  @i2cctl: Current value of I2CCTL register
  *
  *  Raises the I2C clock line '0'->'1'
+ *  Negates the I2C clock output enable on X550 hardware.
  **/
 static void ixgbe_raise_i2c_clk(struct ixgbe_hw *hw, u32 *i2cctl)
 {
+	u32 clk_oe_bit = IXGBE_I2C_CLK_OE_N_EN(hw);
 	u32 i = 0;
 	u32 timeout = IXGBE_I2C_CLOCK_STRETCHING_TIMEOUT;
 	u32 i2cctl_r = 0;
 
+	if (clk_oe_bit) {
+		*i2cctl |= clk_oe_bit;
+		IXGBE_WRITE_REG(hw, IXGBE_I2CCTL(hw), *i2cctl);
+	}
+
 	for (i = 0; i < timeout; i++) {
 		*i2cctl |= IXGBE_I2C_CLK_OUT(hw);
 		IXGBE_WRITE_REG(hw, IXGBE_I2CCTL(hw), *i2cctl);
@@ -2185,11 +2221,13 @@ static void ixgbe_raise_i2c_clk(struct ixgbe_hw *hw, u32 *i2cctl)
  *  @i2cctl: Current value of I2CCTL register
  *
  *  Lowers the I2C clock line '1'->'0'
+ *  Asserts the I2C clock output enable on X550 hardware.
  **/
 static void ixgbe_lower_i2c_clk(struct ixgbe_hw *hw, u32 *i2cctl)
 {
 
 	*i2cctl &= ~IXGBE_I2C_CLK_OUT(hw);
+	*i2cctl &= ~IXGBE_I2C_CLK_OE_N_EN(hw);
 
 	IXGBE_WRITE_REG(hw, IXGBE_I2CCTL(hw), *i2cctl);
 	IXGBE_WRITE_FLUSH(hw);
@@ -2205,13 +2243,17 @@ static void ixgbe_lower_i2c_clk(struct ixgbe_hw *hw, u32 *i2cctl)
  *  @data: I2C data value (0 or 1) to set
  *
  *  Sets the I2C data bit
+ *  Asserts the I2C data output enable on X550 hardware.
  **/
 static s32 ixgbe_set_i2c_data(struct ixgbe_hw *hw, u32 *i2cctl, bool data)
 {
+	u32 data_oe_bit = IXGBE_I2C_DATA_OE_N_EN(hw);
+
 	if (data)
 		*i2cctl |= IXGBE_I2C_DATA_OUT(hw);
 	else
 		*i2cctl &= ~IXGBE_I2C_DATA_OUT(hw);
+	*i2cctl &= ~data_oe_bit;
 
 	IXGBE_WRITE_REG(hw, IXGBE_I2CCTL(hw), *i2cctl);
 	IXGBE_WRITE_FLUSH(hw);
@@ -2219,6 +2261,14 @@ static s32 ixgbe_set_i2c_data(struct ixgbe_hw *hw, u32 *i2cctl, bool data)
 	/* Data rise/fall (1000ns/300ns) and set-up time (250ns) */
 	udelay(IXGBE_I2C_T_RISE + IXGBE_I2C_T_FALL + IXGBE_I2C_T_SU_DATA);
 
+	if (!data)	/* Can't verify data in this case */
+		return 0;
+	if (data_oe_bit) {
+		*i2cctl |= data_oe_bit;
+		IXGBE_WRITE_REG(hw, IXGBE_I2CCTL(hw), *i2cctl);
+		IXGBE_WRITE_FLUSH(hw);
+	}
+
 	/* Verify data was set correctly */
 	*i2cctl = IXGBE_READ_REG(hw, IXGBE_I2CCTL(hw));
 	if (data != ixgbe_get_i2c_data(hw, i2cctl)) {
@@ -2235,9 +2285,19 @@ static s32 ixgbe_set_i2c_data(struct ixgbe_hw *hw, u32 *i2cctl, bool data)
  *  @i2cctl: Current value of I2CCTL register
  *
  *  Returns the I2C data bit value
+ *  Negates the I2C data output enable on X550 hardware.
  **/
 static bool ixgbe_get_i2c_data(struct ixgbe_hw *hw, u32 *i2cctl)
 {
+	u32 data_oe_bit = IXGBE_I2C_DATA_OE_N_EN(hw);
+
+	if (data_oe_bit) {
+		*i2cctl |= data_oe_bit;
+		IXGBE_WRITE_REG(hw, IXGBE_I2CCTL(hw), *i2cctl);
+		IXGBE_WRITE_FLUSH(hw);
+		udelay(IXGBE_I2C_T_FALL);
+	}
+
 	if (*i2cctl & IXGBE_I2C_DATA_IN(hw))
 		return true;
 	return false;
@@ -2252,10 +2312,11 @@ static bool ixgbe_get_i2c_data(struct ixgbe_hw *hw, u32 *i2cctl)
  **/
 static void ixgbe_i2c_bus_clear(struct ixgbe_hw *hw)
 {
-	u32 i2cctl = IXGBE_READ_REG(hw, IXGBE_I2CCTL(hw));
+	u32 i2cctl;
 	u32 i;
 
 	ixgbe_i2c_start(hw);
+	i2cctl = IXGBE_READ_REG(hw, IXGBE_I2CCTL(hw));
 
 	ixgbe_set_i2c_data(hw, &i2cctl, 1);