Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757229Ab0DFRs7 (ORCPT ); Tue, 6 Apr 2010 13:48:59 -0400 Received: from mail-pv0-f174.google.com ([74.125.83.174]:44256 "EHLO mail-pv0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753224Ab0DFRsx (ORCPT ); Tue, 6 Apr 2010 13:48:53 -0400 From: Kevin Hilman To: linux-i2c@vger.kernel.org, Ben Dooks Cc: Dirk Behme , Sudhakar Rajashekhara , Alexander Vasiliev , Brad Griffis , Dirk Behme , "Jean Delvare (PC drivers, core)" , "Ben Dooks (embedded platforms)" , Kevin Hilman , Chaithrika U S , Philby John , "Srinivasan, Nageswari" , linux-kernel@vger.kernel.org Subject: [PATCH 1/6] i2c: davinci: Fix smbus Oops with AIC33 usage Date: Tue, 6 Apr 2010 10:42:13 -0700 Message-Id: <1270575738-22388-2-git-send-email-khilman@deeprootsystems.com> X-Mailer: git-send-email 1.7.0.2 In-Reply-To: <1270575738-22388-1-git-send-email-khilman@deeprootsystems.com> References: <1270575738-22388-1-git-send-email-khilman@deeprootsystems.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3911 Lines: 115 From: Dirk Behme This fixes Oops at kernel startup while "scanning" for TLV320AIC23IDx addresses. Additional fix from Sudhakar Rajashekhara: I think 'first byte set' should come after the write because an I2C transaction is being carried out before configuring the I2C mode register (which has bits to configure Master, Start condition etc), which causes undefined behavior. Signed-off-by: Sudhakar Rajashekhara Signed-off-by: Alexander Vasiliev Signed-off-by: Brad Griffis Signed-off-by: Dirk Behme Acked-by: Kevin Hilman --- drivers/i2c/busses/i2c-davinci.c | 31 +++++++++++++++++++++++++++---- 1 files changed, 27 insertions(+), 4 deletions(-) diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c index c89687a..3b9ab23 100644 --- a/drivers/i2c/busses/i2c-davinci.c +++ b/drivers/i2c/busses/i2c-davinci.c @@ -112,6 +112,7 @@ struct davinci_i2c_dev { u8 *buf; size_t buf_len; int irq; + int stop; u8 terminate; struct i2c_adapter adapter; }; @@ -249,9 +250,6 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop) u16 w; int r; - if (msg->len == 0) - return -EINVAL; - if (!pdata) pdata = &davinci_i2c_platform_data_default; /* Introduce a delay, required for some boards (e.g Davinci EVM) */ @@ -263,6 +261,7 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop) dev->buf = msg->buf; dev->buf_len = msg->len; + dev->stop = stop; davinci_i2c_write_reg(dev, DAVINCI_I2C_CNT_REG, dev->buf_len); @@ -280,6 +279,10 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop) flag |= DAVINCI_I2C_MDR_TRX; if (stop) flag |= DAVINCI_I2C_MDR_STP; + if (msg->len == 0) { + flag |= DAVINCI_I2C_MDR_RM; + flag &= ~DAVINCI_I2C_MDR_STP; + } /* Enable receive or transmit interrupts */ w = davinci_i2c_read_reg(dev, DAVINCI_I2C_IMR_REG); @@ -290,9 +293,21 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop) davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w); dev->terminate = 0; + /* write the data into mode register */ davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag); + /* + * First byte should be set here, not after interrupt, + * because transmit-data-ready interrupt can come before + * NACK-interrupt during sending of previous message and + * ICDXR may have wrong data + */ + if ((!(msg->flags & I2C_M_RD)) && dev->buf_len) { + davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG, *dev->buf++); + dev->buf_len--; + } + r = wait_for_completion_interruptible_timeout(&dev->cmd_complete, dev->adapter.timeout); if (r == 0) { @@ -371,7 +386,7 @@ i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num) static u32 i2c_davinci_func(struct i2c_adapter *adap) { - return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK); + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; } static void terminate_read(struct davinci_i2c_dev *dev) @@ -430,6 +445,14 @@ static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id) case DAVINCI_I2C_IVR_ARDY: davinci_i2c_write_reg(dev, DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_ARDY); + if (((dev->buf_len == 0) && (dev->stop != 0)) || + (dev->cmd_err & DAVINCI_I2C_STR_NACK)) { + w = davinci_i2c_read_reg(dev, + DAVINCI_I2C_MDR_REG); + w |= DAVINCI_I2C_MDR_STP; + davinci_i2c_write_reg(dev, + DAVINCI_I2C_MDR_REG, w); + } complete(&dev->cmd_complete); break; -- 1.7.0.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/