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authorNishanth Menon <nm@ti.com>2009-08-20 20:21:14 +0400
committerBen Dooks <ben-linux@fluff.org>2009-08-21 01:27:57 +0400
commitdcc4ec26942d3bae2c5a82ab8346ab53b540a171 (patch)
tree5610adf8611c1c34907d55ad3e537da943ec70fd
parent64f1607ffbbc772685733ea63e6f7f4183df1b16 (diff)
downloadlinux-dcc4ec26942d3bae2c5a82ab8346ab53b540a171.tar.xz
i2c-omap: Fix I2C status ACK
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. Signed-off-by: Nishanth Menon <nm@ti.com> Signed-off-by: Moiz Sonasath <m-sonasath@ti.com> Signed-off-by: Ben Dooks <ben-linux@fluff.org>
-rw-r--r--drivers/i2c/busses/i2c-omap.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index d258b02aef44..94639d0aabd5 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -674,7 +674,14 @@ omap_i2c_isr(int this_irq, void *dev_id)
err = 0;
complete:
- omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, stat);
+ /*
+ * Ack the stat in one go, but [R/X]DR and [R/X]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));
if (stat & OMAP_I2C_STAT_NACK) {
err |= OMAP_I2C_STAT_NACK;