lkml.org 
[lkml]   [2015]   [Dec]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v2] I2C: designware: fix IO timeout issue for AMD controller
From
Date
On 12/11/2015 02:02 PM, Xiangliang Yu wrote:
> Because of some hardware limitation, AMD I2C controller can't
> trigger pending interrupt if interrupt status has been changed
> after clearing interrupt status bits. Then, I2C will lost
> interrupt and IO timeout.
>
> According to hardware design, this patch implements a workaround
> to disable i2c controller interrupt and re-enable i2c interrupt
> before exiting ISR.
>
> To reduce the performance impacts on other vendors, use unlikely
> function to check flag in ISR.
> ---
> Changes in v2:
> - pass flags with ->driver_data
> - unmask interrupt right after masking
>
> Signed-off-by: Xiangliang Yu <Xiangliang.Yu@amd.com>
> ---
> drivers/i2c/busses/i2c-designware-core.c | 6 ++++++
> drivers/i2c/busses/i2c-designware-core.h | 1 +
> drivers/i2c/busses/i2c-designware-platdrv.c | 7 ++++++-
> 3 files changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c
> index 8c48b27..de7fbbb 100644
> --- a/drivers/i2c/busses/i2c-designware-core.c
> +++ b/drivers/i2c/busses/i2c-designware-core.c
> @@ -813,6 +813,12 @@ static irqreturn_t i2c_dw_isr(int this_irq, void *dev_id)
> tx_aborted:
> if ((stat & (DW_IC_INTR_TX_ABRT | DW_IC_INTR_STOP_DET)) || dev->msg_err)
> complete(&dev->cmd_complete);
> + else if (unlikely(dev->accessor_flags & ACCESS_INTR_MASK)) {
> + /* workaround to trigger pending interrupt */
> + stat = dw_readl(dev, DW_IC_INTR_MASK);
> + i2c_dw_disable_int(dev);
> + dw_writel(dev, stat, DW_IC_INTR_MASK);
> + }
>
Looks ok to me.

Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>


\
 
 \ /
  Last update: 2015-12-11 10:01    [W:0.046 / U:1.824 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site