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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
|
