From dcc4ec26942d3bae2c5a82ab8346ab53b540a171 Mon Sep 17 00:00:00 2001 From: Nishanth Menon Date: Thu, 20 Aug 2009 11:21:14 -0500 Subject: 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 Signed-off-by: Moiz Sonasath Signed-off-by: Ben Dooks --- drivers/i2c/busses/i2c-omap.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'drivers/i2c') 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; -- cgit v1.2.2