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Re: [PATCH v5 0/6] bcm2835: auxiliar device support for spi

From Martin Sperl <kernel@martin.sperl.org>
Newsgroups linux.kernel
Subject Re: [PATCH v5 0/6] bcm2835: auxiliar device support for spi
Date 2015-09-10 18:00 +0200
Message-ID <q7cqt-5Zm-1@gated-at.bofh.it> (permalink)
References <q4VN8-6Mk-3@gated-at.bofh.it> <q6CGm-5cz-3@gated-at.bofh.it> <q7cgO-5NY-27@gated-at.bofh.it>
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> On 10.09.2015, at 17:48, Noralf Trønnes <noralf@tronnes.org> wrote:
> 
> This looks interesting.
> But there's a challenge with the uart1 and the 8250 driver.
> 
> Phil Elwell has this to say:
> This means that that UART1 isn't an exact clone of a 8250 UART.
> In a particular, the clock divisor is calculated differently.
> A standard 8250 derives the baud rate as clock/(divisor16),
> whereas the BCM2835 mini UART uses clock/(divisor8). This means
> that if you want to use the standard driver then you need to lie
> about the clock frequency, providing a value is twice the real
> value, in order for a suitable divisor to be calculated.
> 
> Ref: https://github.com/raspberrypi/linux/pull/1008#issuecomment-139234607
> 
> So either we need a new uart1 driver or a doubled clock freq. somehow.

Found out the same thing and communicated it to Eric - not 
knowing about the different divider…

Martin--
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Thread

Re: [PATCH v5 0/6] bcm2835: auxiliar device support for spi Eric Anholt <eric@anholt.net> - 2015-09-09 03:50 +0200
  Re: [PATCH v5 0/6] bcm2835: auxiliar device support for spi Alexander Stein <alexanders83@web.de> - 2015-09-09 11:10 +0200
    Re: [PATCH v5 0/6] bcm2835: auxiliar device support for spi Eric Anholt <eric@anholt.net> - 2015-09-09 20:30 +0200
  Re: [PATCH v5 0/6] bcm2835: auxiliar device support for spi Noralf Trønnes <noralf@tronnes.org> - 2015-09-10 17:50 +0200
    Re: [PATCH v5 0/6] bcm2835: auxiliar device support for spi Martin Sperl <kernel@martin.sperl.org> - 2015-09-10 18:00 +0200
      Re: [PATCH v5 0/6] bcm2835: auxiliar device support for spi Phil Elwell <phil@raspberrypi.org> - 2015-09-10 19:10 +0200

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