Thread (6 messages) 6 messages, 5 authors, 2021-12-15

RE: [PATCH v2] serial-uartlite: Remove an un-necessary read of control register

From: Shubhrajyoti Datta <hidden>
Date: 2021-11-24 12:39:31

-----Original Message-----
From: Greg KH <gregkh@linuxfoundation.org>
Sent: Wednesday, November 24, 2021 3:38 PM
To: Shubhrajyoti Datta <redacted>
Cc: linux-serial@vger.kernel.org; jirislaby@kernel.org; jacmet@sunsite.dk; git
[off-list ref]
Subject: Re: [PATCH v2] serial-uartlite: Remove an un-necessary read of control
register

On Tue, Nov 23, 2021 at 06:43:48PM +0530, Shubhrajyoti Datta wrote:
quoted
The control register is a writeonly register that's why reading it
doesn't make any sense.
The manual states "This is a write-only register. Issuing a read
request to the control register generates the read acknowledgment with zero
data."

Are you sure this is ok to remove?  Usually you have to do a read after a write to
ensure that the write succeeded.

What ensures that the write succeeded now if you remove this read?
I do not find the mention of a read requirement in the manual. 
Also in the current code in ulite_console_write and in ulite_startup we are writing without a 
read. 

Thanks and Regards,
Shubhrajyoti
thanks,

greg k-h
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