Hack to add I2C zero length transfers and SMBus quick mode necessary for AIC23 sound again. Signed-off-by: Dirk Behme <dirk.behme_at_gmail.com> -------------- next part -------------- Index: linux-osk/drivers/i2c/busses/i2c-omap.c =================================================================== --- linux-osk.orig/drivers/i2c/busses/i2c-omap.c +++ linux-osk/drivers/i2c/busses/i2c-omap.c @@ -285,20 +285,29 @@ static int omap_i2c_xfer_msg(struct i2c_ struct i2c_msg *msg, int stop) { struct omap_i2c_dev *dev = i2c_get_adapdata(adap); + u8 zero_byte = 0; int r; u16 w; dev_dbg(dev->dev, "addr: 0x%04x, len: %d, flags: 0x%x, stop: %d\n", msg->addr, msg->len, msg->flags, stop); - if (msg->len == 0) - return -EINVAL; - omap_i2c_write_reg(dev, OMAP_I2C_SA_REG, msg->addr); - /* REVISIT: Could the STB bit of I2C_CON be used with probing? */ - dev->buf = msg->buf; - dev->buf_len = msg->len; + /* Sigh, seems we can't do zero length transactions. Thus, we + * can't probe for devices w/o actually sending/receiving at least + * a single byte. So we'll set count to 1 for the zero length + * transaction case and hope we don't cause grief for some + * arbitrary device due to random byte write/read during + * probes. + */ + if (msg->len == 0) { + dev->buf = &zero_byte; + dev->buf_len = 1; + } else { + dev->buf = msg->buf; + dev->buf_len = msg->len; + } omap_i2c_write_reg(dev, OMAP_I2C_CNT_REG, dev->buf_len); @@ -383,7 +392,7 @@ out: static u32 omap_i2c_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 inline void