From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752689AbcGGN6V (ORCPT ); Thu, 7 Jul 2016 09:58:21 -0400 Received: from mail-pf0-f173.google.com ([209.85.192.173]:34912 "EHLO mail-pf0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751131AbcGGN6M (ORCPT ); Thu, 7 Jul 2016 09:58:12 -0400 From: Tim Harvey To: Wolfram Sang Cc: Fabio Estevam , linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] i2c: imx: add retries for i2c-0 on Ventana boards Date: Thu, 7 Jul 2016 07:03:49 -0700 Message-Id: <1467900229-5262-1-git-send-email-tharvey@gateworks.com> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Gateworks Ventana IMX6 based boards have a Gateworks System Controller [1] (gsc) device that can NAK i2c transactions when its busy in an ADC loop. As this is always on i2c-0 we will add retries for that bus for any Ventana board. Signed-off-by: Tim Harvey --- drivers/i2c/busses/i2c-imx.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c index 1844bc9..aec71c3 100644 --- a/drivers/i2c/busses/i2c-imx.c +++ b/drivers/i2c/busses/i2c-imx.c @@ -460,6 +460,8 @@ static int i2c_imx_acked(struct imx_i2c_struct *i2c_imx) { if (imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR) & I2SR_RXAK) { dev_dbg(&i2c_imx->adapter.dev, "<%s> No ACK\n", __func__); + if (i2c_imx->adapter.retries) + return -EAGAIN; return -ENXIO; /* No ACK */ } @@ -1068,6 +1070,16 @@ static int i2c_imx_probe(struct platform_device *pdev) i2c_imx->adapter.dev.of_node = pdev->dev.of_node; i2c_imx->base = base; + /* + * The Gateworks Ventana has an i2c based system controller on i2c-0 + * which emulates several standard i2c devices with existing drivers. + * That device can NAK when its in an ADC loop. Add bus retries. + */ + if (of_machine_is_compatible("gw,ventana") && phy_addr == 0x021a0000) { + dev_info(&pdev->dev, "Adding retries for Ventana GSC\n"); + i2c_imx->adapter.retries = 3; + } + /* Get I2C clock */ i2c_imx->clk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(i2c_imx->clk)) { -- 1.9.1