On 21.01.2023 21:32, Daniel Santos wrote:
Hello all,
I saw this a few days ago, but was too busy to answer then -- sorry
about that. I've dug into this code a bit, but for the mt7620.
On 1/21/23 08:51, Sergio Paracuellos wrote:
Hi,
[+cc John Crispin]
On Sat, Jan 21, 2023 at 2:45 PM Arınç ÜNAL <arinc.u...@arinc9.com> wrote:
On 21.01.2023 10:56, Sergio Paracuellos wrote:
Hi,
On Sat, Jan 21, 2023 at 7:03 AM Arınç ÜNAL <arinc.u...@arinc9.com>
wrote:
Pins from 22 to 33 are on the rgmii2 pin group. They don't function as
GPIO by default. Requesting a gpio by either from devicetree or `echo
203 > /sys/class/gpio/export` won't change anything. You have to
claim
the pin group as gpio on the devicetree.
Yes, you have to claim the pin group as gpio on the device tree to
make this work. Ralink has the concept of "GPIO mode" but actually is
just an electrical configuration for a certain device. So if the mode
(function) is not requested as a real GPIO nothing is going to work.
So in your board's dts file you have to add something like the
following with the groups you want to claim as real gpio function:
#include "mt7621.dtsi"
...
&state_default {
gpio {
groups = "jtag", "uart3", "wdt";
function = "gpio";
};
};
First of all, to better understand what you're working with I highly
recommend you download the mt7621 Data Sheet and took at §2.4 Pin
Sharing Schemes. Here's a link to one I've found:
https://www.t-firefly.com/download/FireWRT/hardware/MT7621.pdf .
Microcontrollers come with a lot of nifty hardware -- more than they
have external pins for. So if you don't need a piece of hardware, you
can option to use that pin as a GPIO instead.
The kernel code for the other end of this device tree snippet that
Sergio gave you is in arch/mips/ralink/mt7621.c, which you'll probably
find in your OpenWRT build tree under
build_dir/target-mipsel_24kc_musl/linux-ramips_mt7620/linux-5.4.143/.
The various struct rt2880_pmx_func variables contain the valid values
for each of these sets of pins except for "gpio" -- which is implicit
for each one (not my favorite design choice, but oh well). Finally, each
of those are glued together with the struct rt2880_pmx_group
mt7621_pinmux_data[] array on line 96. You can use this to see what the
valid values are for each group, because until this all goes yaml,
there's nothing to tell you if you've used an invalid value.
Speaking of which:
https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl.git/commit/?h=for-next&id=4e5410668af5475681793df2bb8c7d8dc6f9c327
https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl.git/commit/?h=for-next&id=0c9a567651c3b5d433429da2c7d8e8406ddf1076
https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl.git/commit/?h=for-next&id=b4ac84395820eaa0b99ec56816e53c9386ca8b38
https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl.git/commit/?h=for-next&id=d648fd64e10d9d1609146d0c4e47b0f5988e2a2b
https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl.git/commit/?h=for-next&id=844bca60927f3aae6baafafb1edd218b624254a1
Arınç
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