Subject: Re: [PATCH v14] ath10k: add LED and GPIO controlling support for various chipsets

From: Kalle Valo <[email-masked]>
Date: Fri, 16 Jun 2023 20:03:23 +0300

Christian Marangi <[email-masked]> writes:

> From: Sebastian Gottschall <[email-masked]>
>
> Adds LED and GPIO Control support for 988x, 9887, 9888, 99x0, 9984
> based chipsets with on chipset connected led's using WMI Firmware API.
> The LED device will get available named as "ath10k-phyX" at sysfs and
> can be controlled with various triggers.
> Adds also debugfs interface for gpio control.
>
> Signed-off-by: Sebastian Gottschall <[email-masked]>
> Reviewed-by: Steve deRosier <[email-masked]>
> [kvalo: major reorg and cleanup]
> Signed-off-by: Kalle Valo <[email-masked]>
> [ansuel: rebase and small cleanup]
> Signed-off-by: Christian Marangi <[email-masked]>
> Tested-by: Stefan Lippers-Hollmann <[email-masked]>
> ---
>
> Hi,
> this is a very old patch from 2018 that somehow was talked till 2020
> with Kavlo asked to rebase and resubmit and nobody did.
> So here we are in 2023 with me trying to finally have this upstream.
>
> A summarize of the situation.
> - The patch is from years in OpenWRT. Used by anything that has ath10k
>   card and a LED connected.
> - This patch is also used by the fw variant from Candela Tech with no
>   problem reported.
> - It was pointed out that this caused some problem with ipq4019 SoC
>   but the problem was actually caused by a different bug related to
>   interrupts.
>
> I honestly hope we can have this feature merged since it's really
> funny to have something that was so near merge and jet still not
> present and with devices not supporting this simple but useful
> feature.

Indeed, we should finally get this in. Thanks for working on it.

I did some minor changes to the patch, they are in my pending branch:

https://git.kernel.org/pub/scm/linux/kernel/git/kvalo/ath.git/commit/?h=pending&id=686464864538158f22842dc49eddea6fa50e59c1

My comments below, please review my changes. No need to resend because
of these.

> --- a/drivers/net/wireless/ath/ath10k/Kconfig
> +++ b/drivers/net/wireless/ath/ath10k/Kconfig
> @@ -67,6 +67,23 @@ config ATH10K_DEBUGFS
>  
>  	  If unsure, say Y to make it easier to debug problems.
>  
> +config ATH10K_LEDS
> +	bool "Atheros ath10k LED support"
> +	depends on ATH10K
> +	select MAC80211_LEDS
> +	select LEDS_CLASS
> +	select NEW_LEDS
> +	default y
> +	help
> +	  This option enables LEDs support for chipset LED pins.
> +	  Each pin is connected via GPIO and can be controlled using
> +	  WMI Firmware API.
> +
> +	  The LED device will get available named as "ath10k-phyX" at sysfs and
> +    	  can be controlled with various triggers.
> +
> +	  Say Y, if you have LED pins connected to the ath10k wireless card.

I'm not sure anymore if we should ask anything from the user, better to
enable automatically if LED support is enabled in the kernel. So I
simplified this to:

config ATH10K_LEDS
	bool
	depends on ATH10K
	depends on LEDS_CLASS=y || LEDS_CLASS=MAC80211
	default y

This follows what mt76 does:

config MT76_LEDS
	bool
	depends on MT76_CORE
	depends on LEDS_CLASS=y || MT76_CORE=LEDS_CLASS
	default y

> @@ -65,6 +66,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
>  		.dev_id = QCA988X_2_0_DEVICE_ID,
>  		.bus = ATH10K_BUS_PCI,
>  		.name = "qca988x hw2.0",
> +		.led_pin = 1,
>  		.patch_load_addr = QCA988X_HW_2_0_PATCH_LOAD_ADDR,
>  		.uart_pin = 7,
>  		.cc_wraparound_type = ATH10K_HW_CC_WRAP_SHIFTED_ALL,

I prefer following the field order from struct ath10k_hw_params
declaration and also setting fields explicitly to zero (even though
there are gaps still) so I changed that for every entry.

> +int ath10k_leds_register(struct ath10k *ar)
> +{
> +	int ret;
> +
> +	if (ar->hw_params.led_pin == 0)
> +		/* leds not supported */
> +		return 0;
> +
> +	snprintf(ar->leds.label, sizeof(ar->leds.label), "ath10k-%s",
> +		 wiphy_name(ar->hw->wiphy));
> +	ar->leds.wifi_led.active_low = 1;
> +	ar->leds.wifi_led.gpio = ar->hw_params.led_pin;
> +	ar->leds.wifi_led.name = ar->leds.label;
> +	ar->leds.wifi_led.default_state = LEDS_GPIO_DEFSTATE_KEEP;
> +
> +	ar->leds.cdev.name = ar->leds.label;
> +	ar->leds.cdev.brightness_set_blocking = ath10k_leds_set_brightness_blocking;
> +
> +	/* FIXME: this assignment doesn't make sense as it's NULL, remove it? */
> +	ar->leds.cdev.default_trigger = ar->leds.wifi_led.default_trigger;

But what to do with this FIXME?

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