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From: Kevin Hilman <khilman@deeprootsystems.com>
To: "Govindraj.R" <govindraj.raja@ti.com>
Cc: Olof Johansson <olof@lixom.net>, linux-omap@vger.kernel.org
Subject: Re: [PATCH v5] OMAP UART: Add omap-serial driver support.
Date: Thu, 04 Feb 2010 09:46:40 -0800	[thread overview]
Message-ID: <87iqac51xb.fsf@deeprootsystems.com> (raw)
In-Reply-To: <40204.192.168.10.88.1265298323.squirrel@dbdmail.itg.ti.com> (Govindraj R.'s message of "Thu\, 4 Feb 2010 21\:15\:23 +0530 \(IST\)")

"Govindraj.R" <govindraj.raja@ti.com> writes:

[...]

>>> >> + * @baud: baudrate for which divisor needs to be calculated.
>>> >> + *
>>> >> + * We have written our own function to get the divisor so as to support
>>> >> + * 13x mode.
>>> >> + */
>>> >
>>> > Again, the why, not the how. Why do you need the 13x divisor? What's
>>> > magic about 3Mbaud?
>>> >
>>>
>>> Refering to TRM UART chapter 17:
>>>
>>> Table 17-1. UART Mode Baud Rates, Divisor Values, and Error Rates
>>>
>>> referring to oversampling - divisor value
>>>
>>> baudrate 460,800 to 3,686,400 all have divisor 13
>>>
>>> except 3,000,000 which has divisor value 16
>>>
>>> thus we are checking if baud != 3000000
>>
>> Ok. It's always useful to have just a bit of information in the driver
>> so you don't have to search around the manual when trying to figure out
>> why something was done.
>>
>> Maybe something simple: "3Mbaud is unique in that it requires a divisor
>> of 13. See the TRM for full details".
>
> ok. will add that comments.

Referncing TRM Chapter and Section names (and/or numbers) is very
helpful too.  Usually section names are more helpful since numbers
change w/TRM versions.

Kevin

  reply	other threads:[~2010-02-04 17:46 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-01-27  9:56 [PATCH v5] OMAP UART: Add omap-serial driver support Govindraj.R
2010-01-27 17:25 ` Tony Lindgren
2010-01-27 17:49   ` Kevin Hilman
2010-01-27 17:57     ` Tony Lindgren
2010-01-27 18:07       ` Kevin Hilman
2010-01-27 18:18         ` Tony Lindgren
2010-01-27 19:10           ` Kevin Hilman
2010-01-27 19:33             ` Tony Lindgren
2010-02-10 14:39   ` Govindraj
2010-02-10 17:25     ` Tony Lindgren
2010-01-27 18:20 ` Kevin Hilman
2010-01-27 19:37   ` Kevin Hilman
2010-01-28  3:22 ` Olof Johansson
2010-02-04 15:09   ` Govindraj.R
2010-02-04 15:28     ` Olof Johansson
2010-02-04 15:45       ` Govindraj.R
2010-02-04 17:46         ` Kevin Hilman [this message]
2010-02-04 20:37           ` Olof Johansson
2010-02-04 20:33         ` Olof Johansson

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