i2c: omap: add notes related to i2c multimaster mode
No functional changes.
Signed-off-by: Alexander Kochetkov <al.kochet@gmail.com>
Reviewed-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index b70270d..9f5b57a 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -300,6 +300,12 @@
omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);
/*
+ * NOTE: right after setting CON_EN, STAT_BB could be 0 while the
+ * bus is busy. It will be changed to 1 on the next IP FCLK clock.
+ * udelay(1) will be enough to fix that.
+ */
+
+ /*
* Don't write to this register if the IE state is 0 as it can
* cause deadlock.
*/
@@ -660,7 +666,11 @@
if (!dev->b_hw && stop)
w |= OMAP_I2C_CON_STP;
-
+ /*
+ * NOTE: STAT_BB bit could became 1 here if another master occupy
+ * the bus. IP successfully complete transfer when the bus will be
+ * free again (BB reset to 0).
+ */
omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w);
/*