From c6c7c729a22bfeb8e63eafce48dbaeea20e68703 Mon Sep 17 00:00:00 2001 From: Dirk Behme Date: Fri, 28 Mar 2008 06:16:12 +0100 Subject: [PATCH] i2c: davinci: Fix smbus Oops with AIC33 usage 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 file changed, 27 insertions(+), 4 deletions(-) diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c index 4523364..43913c1 100644 --- a/drivers/i2c/busses/i2c-davinci.c +++ b/drivers/i2c/busses/i2c-davinci.c @@ -113,6 +113,7 @@ struct davinci_i2c_dev { u8 *buf; size_t buf_len; int irq; + int stop; u8 terminate; struct i2c_adapter adapter; }; @@ -250,9 +251,6 @@ 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) */ @@ -264,6 +262,7 @@ 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); @@ -281,6 +280,10 @@ 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); @@ -291,9 +294,21 @@ 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) { @@ -372,7 +387,7 @@ 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) @@ -431,6 +446,14 @@ 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; -- 2.7.4