From: Andrew Jeffery <andrew@codeconstruct.com.au>
To: Glenn Miles <milesg@linux.vnet.ibm.com>, qemu-devel@nongnu.org
Cc: qemu-arm@nongnu.org, clg@kaod.org, joel@jms.id.au, philmd@linaro.org
Subject: Re: [PATCH v3 2/2] misc/pca9552: Let external devices set pca9552 inputs
Date: Fri, 27 Oct 2023 16:38:48 +1030 [thread overview]
Message-ID: <e12e01428066976c2e02af78cb380f808b12865a.camel@codeconstruct.com.au> (raw)
In-Reply-To: <20231024181144.4045056-3-milesg@linux.vnet.ibm.com>
On Tue, 2023-10-24 at 13:11 -0500, Glenn Miles wrote:
> Allow external devices to drive pca9552 input pins by adding
> input GPIO's to the model. This allows a device to connect
> its output GPIO's to the pca9552 input GPIO's.
>
> In order for an external device to set the state of a pca9552
> pin, the pin must first be configured for high impedance (LED
> is off). If the pca9552 pin is configured to drive the pin low
> (LED is on), then external input will be ignored.
>
> Here is a table describing the logical state of a pca9552 pin
> given the state being driven by the pca9552 and an external device:
>
> PCA9552
> Configured
> State
>
> | Hi-Z | Low |
> ------+------+-----+
> External Hi-Z | Hi | Low |
> Device ------+------+-----+
> State Low | Low | Low |
> ------+------+-----+
>
> Signed-off-by: Glenn Miles <milesg@linux.vnet.ibm.com>
Reviewed-by: Andrew Jeffery <andrew@codeconstruct.com.au>
prev parent reply other threads:[~2023-10-27 6:09 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-24 18:11 [PATCH v3 0/2] misc/pca9552: Changes to support powernv10 Glenn Miles
2023-10-24 18:11 ` [PATCH v3 1/2] misc/pca9552: Fix inverted input status Glenn Miles
2023-10-24 18:11 ` [PATCH v3 2/2] misc/pca9552: Let external devices set pca9552 inputs Glenn Miles
2023-10-27 6:08 ` Andrew Jeffery [this message]
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