Re: [PATCH v4 0/2] i2c: i2c-xiic: fix clearing of bnb irq and waiting/ clearing while atomic

[Michal Simek <michal.simek@amd.com>]

+Shubhrajyoti,

On 11/2/26 10:32, Thilo Zirnstein wrote:
> Dear all,
> 
> This patch-series fixes the clearing routine for the bus not busy (bnb) irq
> plus the waiting and clearing routines while in atomic context.
> 
> The bnb is used to indicate that the current transfer is done.
> A high level view of the software flow for tx:
> 
> * init i2c controller
> * prepare all registers ( fill fifo, enable irqs, ... )
> * start i2c txfer
> * clear and enable bnb
> * wait for completion
> * ( serve interrupts )
> * ( bnb interrupt ): complete completion
> 
> The datasheet ( pg090-axi-iic, Interrupt-Status-Register ISR)
> states that the bnb bit can only be cleared if
> the bus busy bit in the status register is set.
> So the iic controller must have recognized that their is some activity
> on the bus. ( Start condition )
> 
> Currently the bnb bit is cleared without checking or waiting for this
> condition. This can lead to spurious bnb interrupts.
> 
> Andi suggested to use an atomic-save function to wait for bnb.
> This was applied for other waiting/ clearing functions, too.
> 
> Kind regards,
> 
> Thilo Zirnstein
> ---
> Changes in v4
> - Fix timeout argument of polling in atomic context
> 
> Changes in v3
> - Use atomic-save functions for waiting and clearing.
> - Fix intendation
> - Unintentional changes removed
> 
> Changes in v2:
> - Unintentional changes removed.
> ---
> 
> Thilo Zirnstein (2):
>    i2c: i2c-xiic: fix clearing of bnb irq
>    i2c: i2c-xiic: fix waiting/clearing while atomic
> 
>   drivers/i2c/busses/i2c-xiic.c | 70 ++++++++++++++++++++++++++++-------
>   1 file changed, 57 insertions(+), 13 deletions(-)
> 
Shubhrajyoti: Please review this patch.

Thanks,
Michal