According to I2C specification the NACK should be handled as folowing: "When SDA remains HIGH during this ninth clock pulse, this is defined as the Not Acknowledge signal. The master can then gene rate either a STOP condition to abort the transfer, or a repeated START condition to start a new transfer." [http://www.nxp.com/documents/user_manual/UM10204.pdf] The same is recomened by TI I2C wiki: http://processors.wiki.ti.com/index.php/I2C_Tips Currently, the OMAP I2C driver interrupts I2C trunsfer in case of NACK, but It queries Stop condition OMAP_I2C_CON_REG.STP=1 only if NACK has been received during the last message transmitting/recieving. This may lead to stuck Bus in "Bus Busy" until I2C IP reset (idle/enable). Hence, fix it by querying Stop condition (STP) always when NACK is received. CC: Kevin Hilman <khilman@xxxxxxxxxx> CC: Felipe Balbi <balbi@xxxxxx> Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx> --- drivers/i2c/busses/i2c-omap.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c index 46fb8a5..b3daf3f 100644 --- a/drivers/i2c/busses/i2c-omap.c +++ b/drivers/i2c/busses/i2c-omap.c @@ -618,11 +618,10 @@ static int omap_i2c_xfer_msg(struct i2c_adapter *adap, if (dev->cmd_err & OMAP_I2C_STAT_NACK) { if (msg->flags & I2C_M_IGNORE_NAK) return 0; - if (stop) { - w = omap_i2c_read_reg(dev, OMAP_I2C_CON_REG); - w |= OMAP_I2C_CON_STP; - omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w); - } + + w = omap_i2c_read_reg(dev, OMAP_I2C_CON_REG); + w |= OMAP_I2C_CON_STP; + omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w); return -EREMOTEIO; } return -EIO; -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
