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Re: [PATCH 06/11] hw/gpio/pl061: Honour Luminary PL061 PUR and PDR regis

From: Richard Henderson
Subject: Re: [PATCH 06/11] hw/gpio/pl061: Honour Luminary PL061 PUR and PDR registers
Date: Tue, 6 Jul 2021 18:29:47 -0700
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0

On 7/2/21 3:40 AM, Peter Maydell wrote:
The Luminary variant of the PL061 has registers GPIOPUR and GPIOPDR
which lets the guest configure whether the GPIO lines are pull-up,
pull-down, or truly floating. Instead of assuming all lines are pulled
high, honour the PUR and PDR registers.

For the plain PL061, continue to assume that lines have an external
pull-up resistor, as we did before.

The stellaris board actually relies on this behaviour -- the CD line
of the ssd0323 display device is connected to GPIO output C7, and it
is only because of a different bug which we're about to fix that we
weren't incorrectly driving this line high on reset and putting the
ssd0323 into data mode.

Signed-off-by: Peter Maydell<peter.maydell@linaro.org>
  hw/gpio/pl061.c      | 58 +++++++++++++++++++++++++++++++++++++++++---
  hw/gpio/trace-events |  2 +-
  2 files changed, 55 insertions(+), 5 deletions(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>


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