From: Andrew Lunn <andrew@lunn.ch>
To: Fabio Estevam <festevam@gmail.com>
Cc: kernel@pengutronix.de, shawnguo@kernel.org, linux-imx@nxp.com,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 2/4] ARM: dts: imx6ul-14x14-evk: Enable the GPIO expander
Date: Fri, 8 Jan 2021 02:02:54 +0100 [thread overview]
Message-ID: <X/evPvypdZT6VZAN@lunn.ch> (raw)
In-Reply-To: <20210107235044.7897-2-festevam@gmail.com>
On Thu, Jan 07, 2021 at 08:50:42PM -0300, Fabio Estevam wrote:
> Currently the 74LV595PW GPIO expander is not functional because its OE
> pin is not driven low.
>
> Make it funcional by passing the 'enable-gpios' property inside the
> GPIO expander node.
>
> After putting the OE pin in low state, the outputs of the 74LV595PW all
> go low.
>
> The two KSZ8081 Ethernet PHYs reset lines are driven from the
> the GPIO expander and as they remain low, this causes the Ethernet
> PHYs not to be detected.
>
> There is one solution to this problem as suggested by Andrew Lunn:
>
> "Some devices will respond to MDIO while held in reset, some don't.
> If your PHYs don't you need to add a compatible of the form
> ethernet-phy-id[a-f0-9]{4}\\.[a-f0-9]{4}$ with the PHY ID. The PHY
> will then be probed, independent of if it can be found on the bus or
> not, and that probing will enable the GPIO."
>
> So pass the "ethernet-phy-id0022.1560" for the KSZ8081 PHYs so that they
> both can be functional after 74LV595PW is activated.
>
> Suggested-by: Andrew Lunn <andrew@lunn.ch>
> Signed-off-by: Fabio Estevam <festevam@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Andrew
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next prev parent reply other threads:[~2021-01-08 1:05 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-07 23:50 [PATCH 1/4] ARM: dts: imx6ul-14x14-evk: Fix SPI chipselect polarity Fabio Estevam
2021-01-07 23:50 ` [PATCH 2/4] ARM: dts: imx6ul-14x14-evk: Enable the GPIO expander Fabio Estevam
2021-01-08 1:02 ` Andrew Lunn [this message]
2021-01-18 0:10 ` Shawn Guo
2021-01-07 23:50 ` [PATCH 3/4] ARM: dts: imx6ul-14x14-evk: Describe the KSZ8081 reset Fabio Estevam
2021-01-08 1:03 ` Andrew Lunn
2021-01-18 0:10 ` Shawn Guo
2021-03-10 11:04 ` Joakim Zhang
2021-03-11 11:33 ` Joakim Zhang
2021-03-11 14:17 ` Andrew Lunn
2021-03-12 2:02 ` Joakim Zhang
2021-03-12 11:34 ` Fabio Estevam
2021-01-07 23:50 ` [PATCH 4/4] ARM: dts: imx6ul-14x14-evk: Add camera support Fabio Estevam
2021-01-18 0:11 ` Shawn Guo
2021-01-18 0:09 ` [PATCH 1/4] ARM: dts: imx6ul-14x14-evk: Fix SPI chipselect polarity Shawn Guo
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