From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Kirsher Subject: [net-next 6/6] ixgbe: add I2C clock stretching Date: Sat, 14 Apr 2012 02:16:31 -0700 Message-ID: <1334394991-5839-7-git-send-email-jeffrey.t.kirsher@intel.com> References: <1334394991-5839-1-git-send-email-jeffrey.t.kirsher@intel.com> Cc: Don Skidmore , netdev@vger.kernel.org, gospo@redhat.com, sassmann@redhat.com, Jeff Kirsher To: davem@davemloft.net Return-path: Received: from mga14.intel.com ([143.182.124.37]:21304 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752948Ab2DNJQh (ORCPT ); Sat, 14 Apr 2012 05:16:37 -0400 In-Reply-To: <1334394991-5839-1-git-send-email-jeffrey.t.kirsher@intel.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Don Skidmore This patch adds support for I2C clock stretching which is required per SFF-8636. Customers with passive DA cables implement clock stretching would fail without this patch. Signed-off-by: Don Skidmore Tested-by: Phil Schmitt Signed-off-by: Jeff Kirsher --- drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c | 20 ++++++++++++++------ drivers/net/ethernet/intel/ixgbe/ixgbe_type.h | 1 + 2 files changed, 15 insertions(+), 6 deletions(-) diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c index bf9f82f..2411770 100644 --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c @@ -1582,13 +1582,21 @@ static s32 ixgbe_clock_out_i2c_bit(struct ixgbe_hw *hw, bool data) **/ static void ixgbe_raise_i2c_clk(struct ixgbe_hw *hw, u32 *i2cctl) { - *i2cctl |= IXGBE_I2C_CLK_OUT; - - IXGBE_WRITE_REG(hw, IXGBE_I2CCTL, *i2cctl); - IXGBE_WRITE_FLUSH(hw); + u32 i = 0; + u32 timeout = IXGBE_I2C_CLOCK_STRETCHING_TIMEOUT; + u32 i2cctl_r = 0; - /* SCL rise time (1000ns) */ - udelay(IXGBE_I2C_T_RISE); + for (i = 0; i < timeout; i++) { + *i2cctl |= IXGBE_I2C_CLK_OUT; + IXGBE_WRITE_REG(hw, IXGBE_I2CCTL, *i2cctl); + IXGBE_WRITE_FLUSH(hw); + /* SCL rise time (1000ns) */ + udelay(IXGBE_I2C_T_RISE); + + i2cctl_r = IXGBE_READ_REG(hw, IXGBE_I2CCTL); + if (i2cctl_r & IXGBE_I2C_CLK_IN) + break; + } } /** diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_type.h b/drivers/net/ethernet/intel/ixgbe/ixgbe_type.h index ffa6679..4acd9e6 100644 --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_type.h +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_type.h @@ -110,6 +110,7 @@ #define IXGBE_I2C_CLK_OUT 0x00000002 #define IXGBE_I2C_DATA_IN 0x00000004 #define IXGBE_I2C_DATA_OUT 0x00000008 +#define IXGBE_I2C_CLOCK_STRETCHING_TIMEOUT 500 /* Interrupt Registers */ #define IXGBE_EICR 0x00800 -- 1.7.7.6