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Subject[PATCH 4/4] i2c: omap: add notes related to i2c multimaster mode
Date
No functional changes.

Signed-off-by: Alexander Kochetkov <al.kochet@gmail.com>
---
drivers/i2c/busses/i2c-omap.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index 47103e7..4e3642c 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -304,6 +304,12 @@ static void __omap_i2c_init(struct omap_i2c_dev *dev)
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.
*/
@@ -664,7 +670,11 @@ static int omap_i2c_xfer_msg(struct i2c_adapter *adap,

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);

/*
--
1.7.9.5


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