From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E103A86645; Thu, 1 Feb 2024 12:51:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706791888; cv=none; b=YaJnhVeZAG2OydCyxKYXGZR/q0D9f2vpSFdzYmb4OsM4FnfwDS8F9EeWPc/hRt0WdFKHVBe2lhgc4RF5aeB899/ap+qMefO5ZglGLBr/Ynt8z0qD0nhlrLegx/QWzxNQFUIkcHLa+GkR+lI5nZoxw7zoKDBEMbeABIcNSOjdxk8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706791888; c=relaxed/simple; bh=b3tY4mt/lB4gO7ArhC4Qq2/scszVusvI4m/x+JRTHtc=; h=From:To:Cc:Subject:References:Date:In-Reply-To:Message-ID: MIME-Version:Content-Type; b=UnbKGh/Y6Np5xfFQwi3LjbyJwHSjnWPCqM72jK5C93TsthxNQHDWdHaSblcMCnKDeVNfAchk3zkDXCVtmzGL/CABOi3I6S28FNsSTQYEZj5THxwSRQC0afXgv71n2zsAXSUg3m/sHnsDHkwKsW/ZgQIP/IWfRIUHtyQjkZjvBzw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=S5mIdJ2D; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="S5mIdJ2D" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C6465C433C7; Thu, 1 Feb 2024 12:51:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1706791887; bh=b3tY4mt/lB4gO7ArhC4Qq2/scszVusvI4m/x+JRTHtc=; h=From:To:Cc:Subject:References:Date:In-Reply-To:From; b=S5mIdJ2DTmRcdefesWcvtN0+XhsW1YFimKKjIJJ6As9JxWh3H0PlhU35SQlnfASvW b5EOGpLIxpy5YHO0k+gcNFM3rwzV5LFO/YFsm2arMPtcBzC4KGYE35Gvolv7sDUlFG lCGAk3XH+llnyzNpopP8O2gCcXk60ABFvZ5ZkR5suoui7872r1f9pts3iPJDlAzl36 E8zVGIiqEJCoXwAjJOAgJDMD6qvIO78Bnx8+m2B5N2O8AKptsEeo9Fd1dW4afQq4yY RnCxGt0wQzYFSY7AWK5DHv8YaGeaWiN3jLo2UBv52abGp8BUo7SYY93RSIqGdwttPn 5gOExDJchKS0A== From: Kalle Valo To: Andy Shevchenko Cc: Linus Walleij , Toke =?utf-8?Q?H=C3=B8iland?= =?utf-8?Q?-J=C3=B8rgensen?= , Arend van Spriel , Franky Lin , Hante Meuleman , Arnd Bergmann , Lee Jones , Brian Norris , Srinivasan Raju , linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org, brcm80211-dev-list.pdl@broadcom.com Subject: Re: [PATCH 1/6] wifi: ath9k: Obtain system GPIOS from descriptors References: <20240131-descriptors-wireless-v1-0-e1c7c5d68746@linaro.org> <20240131-descriptors-wireless-v1-1-e1c7c5d68746@linaro.org> Date: Thu, 01 Feb 2024 14:51:23 +0200 In-Reply-To: (Andy Shevchenko's message of "Thu, 1 Feb 2024 13:40:07 +0200") Message-ID: <878r44uz3o.fsf@kernel.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.2 (gnu/linux) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain Andy Shevchenko writes: > On Wed, Jan 31, 2024 at 11:37:20PM +0100, Linus Walleij wrote: > >> The ath9k has an odd use of system-wide GPIOs: if the chip >> does not have internal GPIO capability, it will try to obtain a >> GPIO line from the system GPIO controller: >> >> if (BIT(gpio) & ah->caps.gpio_mask) >> ath9k_hw_gpio_cfg_wmac(...); >> else if (AR_SREV_SOC(ah)) >> ath9k_hw_gpio_cfg_soc(ah, gpio, out, label); >> >> Where ath9k_hw_gpio_cfg_soc() will attempt to issue >> gpio_request_one() passing the local GPIO number of the controller >> (0..31) to gpio_request_one(). >> >> This is somewhat peculiar and possibly even dangerous: there is >> nowadays no guarantee of the numbering of these system-wide >> GPIOs, and assuming that GPIO 0..31 as used by ath9k would >> correspond to GPIOs 0..31 on the system as a whole seems a bit >> wild. >> >> My best guess is that everyone actually using this driver has >> support for the local (custom) GPIO API and the bit in >> h->caps.gpio_mask is always set for any GPIO the driver may >> try to obtain, so this facility to use system-wide GPIOs is >> actually unused and could be deleted. >> >> Anyway: I cannot know if this is really the case, so implement >> a fallback handling using GPIO descriptors obtained from the >> ah->dev device indexed 0..31. These can for example be passed >> in the device tree, ACPI or through board files. I doubt that >> anyone will use them, but this makes it possible to obtain a >> system-wide GPIO for any of the 0..31 GPIOs potentially >> requested by the driver. > > ... > >> + /* Obtains a system specific GPIO descriptor from another GPIO controller */ >> + gpiod = devm_gpiod_get_index(ah->dev, NULL, gpio, flags); > >> + > > Unnecessary blank line, please don't add it. I can fix that in the pending branch, no need to resend because of this. -- https://patchwork.kernel.org/project/linux-wireless/list/ https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches