I2C status ack for [RX]RDR and [RX]RDY could
cause race conditions of clearing the event
twice and a violation of the programing
sequence as defined in TRM This patch fixes
the same.
Issue identified by Jagadeesh Pakaravoor
and Ulrik Bech Hald.
Signed-off-by: Nishanth Menon <nm@xxxxxx>
---
drivers/i2c/busses/i2c-omap.c | 9 ++++++++-
1 files changed, 8 insertions(+), 1 deletions(-)
diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index ece0125..0db0051 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -651,7 +651,14 @@ omap_i2c_isr(int this_irq, void *dev_id)
break;
}
- omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, stat);
+ /*
+ * Ack the stat in one go, but [rx]dr and [rx]rdy should be
+ * acked after the data operation is complete.
+ * Ref: TRM SWPU114Q Figure 18-31
+ */
+ omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, stat &
+ ~(OMAP_I2C_STAT_RRDY | OMAP_I2C_STAT_RDR |
+ OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR));
err = 0;
if (stat & OMAP_I2C_STAT_NACK) {
--
1.5.4.3
--
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