From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Kochetkov Subject: [PATCH 1/2] i2c: omap: fix NACK and Arbitration Lost irq handling Date: Sat, 15 Nov 2014 05:20:51 +0400 Message-ID: <1416014452-6712-1-git-send-email-al.kochet@gmail.com> Return-path: Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: Tony Lindgren , Wolfram Sang , Felipe Balbi , Alexander Kochetkov List-Id: linux-omap@vger.kernel.org commit 1d7afc95946487945cc7f5019b41255b72224b70 (i2c: omap: ack IRQ in parts) changed the interrupt handler to complete transfers without clearing XRDY (AL case) and ARDY (NACK case) flags. XRDY or ARDY interrupt will be fired again (in parallel with omap_i2c_xfer_msg). Interrupt handler will complete transfers second time. As a result, NACK and AL transfers terminates with "transfer timeout" and sometimes client code segfault. The patch restore original logic of handling NACK and AL interrupts and fix race between interrupt handler and omap_i2c_xfer_msg (for AL and NACK case only). Tested on Beagleboard XM C. Signed-off-by: Alexander Kochetkov --- drivers/i2c/busses/i2c-omap.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c index 90dcc2e..9af7095 100644 --- a/drivers/i2c/busses/i2c-omap.c +++ b/drivers/i2c/busses/i2c-omap.c @@ -926,14 +926,12 @@ omap_i2c_isr_thread(int this_irq, void *dev_id) if (stat & OMAP_I2C_STAT_NACK) { err |= OMAP_I2C_STAT_NACK; omap_i2c_ack_stat(dev, OMAP_I2C_STAT_NACK); - break; } if (stat & OMAP_I2C_STAT_AL) { dev_err(dev->dev, "Arbitration lost\n"); err |= OMAP_I2C_STAT_AL; omap_i2c_ack_stat(dev, OMAP_I2C_STAT_AL); - break; } /* -- 1.7.9.5