From mboxrd@z Thu Jan 1 00:00:00 1970 From: Moiz Sonasath Subject: [PATCH 1/3] i2c-omap: Fix I2C status ACK Date: Thu, 20 Aug 2009 11:21:14 -0500 Message-ID: <1250785276-31713-2-git-send-email-m-sonasath@ti.com> References: <1250785276-31713-1-git-send-email-m-sonasath@ti.com> Return-path: In-Reply-To: <1250785276-31713-1-git-send-email-m-sonasath-l0cyMroinI0@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org, Nishanth Menon , Moiz Sonasath List-Id: linux-i2c@vger.kernel.org From: Nishanth Menon 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 --- 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 d258b02..94639d0 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; -- 1.5.6.3