lkml.org 
[lkml]   [2018]   [Feb]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 4/4] i2c: xlp9xx: Check for Bus state after every transfer
From
Date
Hi Wolfram,

Thanks for the review.

On 02/27/2018 01:52 AM, Wolfram Sang wrote:
>
> On Thu, Jan 18, 2018 at 05:39:24AM +0000, George Cherian wrote:
>> I2C bus enters the STOP condition after the DATA_DONE interrupt is raised.
>> Essentially the driver should be checking the bus state before sending
>> the next transaction.
>
> Yes.
>
>> In case the next transaction is initiated while the
>> bus is busy, the prior transactions stop condition is not achieved.
>
> I didn't fully get why you can't check the BUSY bit and wait a little
> just before you push out the next message?
Yes, I am checking for the BUSY bit and looping.
Here for reference

+ while (last_msg && busy_timeout) {
+ status = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_STATUS);
+ if ((status & XLP9XX_I2C_STATUS_BUSY) == 0)
+ break;
+
+ busy_timeout--;
+ udelay(1);
+ }
+
+ if (!busy_timeout) {
+ dev_dbg(priv->dev, "i2c bus busy for too long after transfer\n");
+ return -EIO;
+ }

Did you mean to eliminate the udelay and use msleep?
In any case I will re-post another version of the patch, since
I have found some more issues and need to be fixed.

>
>> Add the check to make sure the bus is not busy before next transaction.
>>

Regards,
-George

\
 
 \ /
  Last update: 2018-02-27 06:01    [W:0.078 / U:0.232 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site