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Groups > linux.kernel > #1373915
| From | Andrew Lunn <andrew@lunn.ch> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH V3] net: emac: emac gigabit ethernet controller driver |
| Date | 2016-04-08 03:00 +0200 |
| Message-ID | <rlsWe-3Tc-7@gated-at.bofh.it> (permalink) |
| References | (2 earlier) <qWlY0-79P-69@gated-at.bofh.it> <qWnGq-8t5-11@gated-at.bofh.it> <rlnMT-h0-43@gated-at.bofh.it> <rlozf-Pg-1@gated-at.bofh.it> <rlpYm-1GR-11@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Thu, Apr 07, 2016 at 04:43:47PM -0500, Timur Tabi wrote:
> On my platform, firmware (UEFI) configures all of the GPIOs. I need
> to get confirmation, but it appears that we don't actually make any
> GPIO calls at all. I see code that looks like this:
>
> for (i = 0; (!adpt->no_mdio_gpio) && i < EMAC_NUM_GPIO; i++) {
> gpio_info = &adpt->gpio_info[i];
> retval = of_get_named_gpio(node, gpio_info->name, 0);
> if (retval < 0)
> return retval;
>
> And on our ACPI system, adpt->no_mdio_gpio is always true:
>
> /* Assume GPIOs required for MDC/MDIO are enabled in firmware */
> adpt->no_mdio_gpio = true;
There are two different things here. One is configuring the pin to be
a GPIO. The second is using the GPIO as a GPIO. In this case,
bit-banging the MDIO bus.
The firmware could be doing the configuration, setting the pin as a
GPIO. However, the firmware cannot be doing the MDIO bit-banging to
make an MDIO bus available. Linux has to do that.
Or it could be we have all completely misunderstood the hardware, and
we are not doing bit-banging GPIO MDIO. There is a real MDIO
controller there, we don't use these pins as GPIOs, etc....
Andrew
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Re: [PATCH V3] net: emac: emac gigabit ethernet controller driver Timur Tabi <timur@codeaurora.org> - 2016-04-07 21:30 +0200
Re: [PATCH V3] net: emac: emac gigabit ethernet controller driver Andrew Lunn <andrew@lunn.ch> - 2016-04-07 22:20 +0200
Re: [PATCH V3] net: emac: emac gigabit ethernet controller driver Timur Tabi <timur@codeaurora.org> - 2016-04-07 23:50 +0200
Re: [PATCH V3] net: emac: emac gigabit ethernet controller driver Andrew Lunn <andrew@lunn.ch> - 2016-04-08 03:00 +0200
Re: [PATCH V3] net: emac: emac gigabit ethernet controller driver Timur Tabi <timur@codeaurora.org> - 2016-04-08 21:10 +0200
Re: [PATCH V3] net: emac: emac gigabit ethernet controller driver Vikram Sethi <vikrams@codeaurora.org> - 2016-04-08 23:20 +0200
Re: [PATCH V3] net: emac: emac gigabit ethernet controller driver Timur Tabi <timur@codeaurora.org> - 2016-04-08 23:50 +0200
Re: [PATCH V3] net: emac: emac gigabit ethernet controller driver Bjorn Andersson <bjorn.andersson@linaro.org> - 2016-04-09 00:50 +0200
Re: [PATCH V3] net: emac: emac gigabit ethernet controller driver Timur Tabi <timur@codeaurora.org> - 2016-04-09 01:10 +0200
Re: [PATCH V3] net: emac: emac gigabit ethernet controller driver Bjorn Andersson <bjorn.andersson@linaro.org> - 2016-04-09 01:30 +0200
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