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Message-ID: <CAKR-sGcgx4p_+k5tC0Z-5y+AQOp6GTQn7pq-WC3xirNiuA0f9g@mail.gmail.com> Date: Sun, 5 Jan 2025 10:31:42 +0100 From: Álvaro Fernández Rojas <noltari@...il.com> To: Jonas Gorski <jonas.gorski@...il.com> Cc: Kyle Hendry <kylehendrydev@...il.com>, linus.walleij@...aro.org, linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org Subject: Re: [PATCH v2] pinctrl: bcm63268: add gpio function El sáb, 4 ene 2025 a las 20:32, Jonas Gorski (<jonas.gorski@...il.com>) escribió: > > On Sat, Jan 4, 2025 at 6:02 PM Álvaro Fernández Rojas <noltari@...il.com> wrote: > > > > El sáb, 4 ene 2025 a las 16:44, Álvaro Fernández Rojas > > (<noltari@...il.com>) escribió: > > > > > > El vie, 3 ene 2025 a las 4:04, Kyle Hendry (<kylehendrydev@...il.com>) escribió: > > > > > > > > On 2024-12-30 08:42, Jonas Gorski wrote: > > > > > Hi, > > > > > > > > > > On Tue, Dec 24, 2024 at 11:41 AM Álvaro Fernández Rojas > > > > > <noltari@...il.com> wrote: > > > > >> From: Kyle Hendry <kylehendrydev@...il.com> > > > > >> > > > > >> There is no guarantee that the bootloader will leave the pin configuration > > > > >> in a known default state, so pinctrl needs to be explicitly set in some > > > > >> cases. This patch adds a gpio function for drivers that need it, i.e. > > > > >> gpio-leds. > > > > >> > > > > >> Signed-off-by: Kyle Hendry <kylehendrydev@...il.com> > > > > >> Signed-off-by: Álvaro Fernández Rojas <noltari@...il.com> > > > > > > > > > > bcm63268-pinctrl implements pinmux_ops::gpio_request_enable(), which > > > > > should automatically set any requested GPIO pin to the GPIO function, > > > > > so explicitly requesting the gpio function for a pin should not be > > > > > needed. Is this not enough? > > > > > > > > > > Best Regards, > > > > > Jonas > > > > > > > > > > > > > > I assumed that as well, but nothing I tried worked with gpio-leds. > > > > gpiochip_generic_request() does call gpio_request_enable(), but gpio-leds > > > > uses devm_fwnode_gpiod_get() which looks like a different code path. The > > > > only place it seems to be configuring the gpio is in create_gpio_led() > > > > where it needs a pinctl node in the device tree. That's just my reading > > > > of the code, though. I haven't set up a ftrace to verify it. > > > > > > > > Best Regards, > > > > Kyle > > > > > > As Kyle pointed out it's not enough and gpio_request_enable() doesn't > > > get called from gpio-leds. > > > I will try to investigate this and report back. > > > > > > Best regards, > > > Álvaro. > > > > I've performed some tests and so far I haven't been able to get > > bcm63268_gpio_request_enable() called. > > > > Even exporting a gpio from userspace doesn't trigger that function, > > which seems strange because in that case we won't have a "gpio" > > function on the pinctrl for that gpio, even with this patch... > > On a first glance it looks like that regmap-gpio does not populate > gpio_chip::request and gpio_chip:free, so the gpio subsystem is not > aware that it needs to request anything. Not sure if just using > gpiolib_generic_request() / gpiolib_generic_free() is fine. Currently > on vacation, so no hardware to test anything at hand ;-) > > Best Regards, > Jonas You're totally right, after adding request() and free() functions to gpio-regmap it's now working without this patch because bcm63268_gpio_request_enable() is now properly called: 1. gpio-keys-polled [ 4.052132] gpio_button_hotplug: loading out-of-tree module taints kernel. [ 4.060657] bcm63268-pinctrl 100000d0.pinctrl: request pin 34 (gpio34) for 100000d0.pinctrl:546 [ 4.069704] bcm63268_gpio_request_enable: range=99a2e0ae offset=34 [ 4.076158] bcm63268-pinctrl 100000d0.pinctrl: request pin 35 (gpio35) for 100000d0.pinctrl:547 [ 4.085135] bcm63268_gpio_request_enable: range=99a2e0ae offset=35 2. gpio-leds [ 4.480190] bcm63268-pinctrl 100000d0.pinctrl: request pin 0 (gpio0) for 100000d0.pinctrl:512 [ 4.489078] bcm63268_gpio_request_enable: range=99a2e0ae offset=0 [ 4.495747] bcm63268-pinctrl 100000d0.pinctrl: request pin 1 (gpio1) for 100000d0.pinctrl:513 [ 4.504600] bcm63268_gpio_request_enable: range=99a2e0ae offset=1 3. userspace gpio export root@...nWrt:~# cat /sys/kernel/debug/gpio gpiochip0: GPIOs 512-563, parent: platform/100000d0.pinctrl, 100000d0.pinctrl: gpio-512 ( |red:mobile ) out lo gpio-513 ( |green:mobile ) out lo gpio-546 ( |wps ) in hi ACTIVE LOW gpio-547 ( |reset ) in hi ACTIVE LOW root@...nWrt:~# echo 545 > /sys/class/gpio/export [ 33.437477] bcm63268-pinctrl 100000d0.pinctrl: request pin 33 (gpio33) for 100000d0.pinctrl:545 [ 33.446503] bcm63268_gpio_request_enable: range=99a2e0ae offset=33 root@...nWrt:~# cat /sys/kernel/debug/gpio gpiochip0: GPIOs 512-563, parent: platform/100000d0.pinctrl, 100000d0.pinctrl: gpio-512 ( |red:mobile ) out lo gpio-513 ( |green:mobile ) out lo gpio-545 ( |sysfs ) in hi gpio-546 ( |wps ) in hi ACTIVE LOW gpio-547 ( |reset ) in hi ACTIVE LOW OpenWrt test source code: https://github.com/Noltari/openwrt/commits/bmips-gpio-tests https://github.com/Noltari/openwrt/commit/d3bc7610c8fe8f713a3e47ed8368b6aa220ae763 Linux test source code: https://github.com/Noltari/linux/commits/gpio-regmap-pinctrl-request-free https://github.com/Noltari/linux/commit/2d0ebb8cad8084e932f40f3f69d4e931b2316aa4 @Linus I assume that adding those functions may cause issues to other drivers and maybe we need to add some logic to add them dynamically based on a new gpio_regmap_config parameter? Best regards, Álvaro.
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