From nobody Mon Dec 15 21:47:53 2025 Received: from relay8-d.mail.gandi.net (relay8-d.mail.gandi.net [217.70.183.201]) (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 923E722A4ED; Wed, 5 Feb 2025 09:55:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.183.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738749354; cv=none; b=KOwMYo8dPwU9lOSU9kiha4LvFUV9Ex1G4b8Pbrrqe/7OlOL+P/Eqb/KFS+NDzEsbYfwPn+2ecCzhShjGZKDsh/GABiDkrtFMBf12Y2hJUdgF8iu1MHNSkiJPF0PJTGoqIVFf8DOdnpKLJnw8AJG6MfZvu109TtVuWpmjuDSipAY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738749354; c=relaxed/simple; bh=juUmvjJB6cYN04ExXM8nyniU2O+Plp7bVycEkuK8aAI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=llkGPt0o33UaUGZRJqtXlcTmIaT+M0fEuL52DWevN77YoIooFc5FAnqw6V8PEWjBTpKa7ufQl75pnGsGZNr3uoovgjjpMc84gT7MgA/d7eX8E6Mh4nTTevyC34mA8ozGd/e7VbHCxIRMhkyLfc8YYX/9yFmkZr25/tX19GSJwhA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=f85GYVav; arc=none smtp.client-ip=217.70.183.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="f85GYVav" Received: by mail.gandi.net (Postfix) with ESMTPA id 6C44C43419; Wed, 5 Feb 2025 09:55:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1738749350; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=r1Q/Kgs+ZlVqX6ytI6zaw2RB7jNNEUJCoJx72kvQuBk=; b=f85GYVavlQpiXP+nIwAuKxYgQlFS65E6POm8Hqwj9Fb8MRvDCMH6J7ji/3TpCY87zMnZ+j 1YMJG7FkuxJrezZvXB83XlJH6Ya7HiTUmZYXGSVnP5e0ZK2tHRNZA2jkvApc8oMwrbyxO5 x8ArXop3f0yagd3yRo1aGGbtVnTyWWGO51Xf04cFKvxjJItdzkz0g2DMWKlXWtzQlu0tIZ avsxCrgFG5B1LJV5prXzf6XhwWeblwNteglHfnX7U7DByeII4zAFxOWEEl+q7bPvS1V5oy +eSR/S+EBjPl/EPzGmBRm7aMlgPXjcekMTZ3NNcfpQhOzOLU5AdFy52ZrIgNlw== From: Herve Codina To: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Herve Codina Cc: linux-pwm@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Luca Ceresoli , Thomas Petazzoni Subject: [PATCH v3 2/2] pwm: Add support for pwm nexus dt bindings Date: Wed, 5 Feb 2025 10:55:43 +0100 Message-ID: <20250205095547.536083-3-herve.codina@bootlin.com> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20250205095547.536083-1-herve.codina@bootlin.com> References: <20250205095547.536083-1-herve.codina@bootlin.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-GND-State: clean X-GND-Score: -100 X-GND-Cause: gggruggvucftvghtrhhoucdtuddrgeefvddrtddtgddvfedufecutefuodetggdotefrodftvfcurfhrohhfihhlvgemucfitefpfffkpdcuggftfghnshhusghstghrihgsvgenuceurghilhhouhhtmecufedtudenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujfgurhephffvvefufffkofgjfhgggfestdekredtredttdenucfhrhhomhepjfgvrhhvvgcuvehoughinhgruceohhgvrhhvvgdrtghoughinhgrsegsohhothhlihhnrdgtohhmqeenucggtffrrghtthgvrhhnpeeuuddtvedthedtgfeugeeujeetueehjeffteevtdeugfffffdufedtuedvgeelfeenucffohhmrghinhepghhithhhuhgsrdgtohhmnecukfhppedvrgdtudemvgdtrgemvdegieemjeejledtmedviegtgeemvgdvvdemiedtfegumeehkegrnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehinhgvthepvdgrtddumegvtdgrmedvgeeimeejjeeltdemvdeitgegmegvvddvmeeitdefugemheekrgdphhgvlhhopehlohgtrghlhhhoshhtrdhlohgtrghlughomhgrihhnpdhmrghilhhfrhhomhephhgvrhhvvgdrtghoughinhgrsegsohhothhlihhnrdgtohhmpdhnsggprhgtphhtthhopedutddprhgtphhtthhopehukhhlvghinhgvkheskhgvrhhnvghlrdhorhhgpdhrtghpthhtoheprhhosghhsehkvghrnhgvlhdrohhrghdprhgtphhtthhopehkrhiikhdoughtsehkvghrnhgvlhdrohhrghdprhgtp hhtthhopegtohhnohhrodgutheskhgvrhhnvghlrdhorhhgpdhrtghpthhtohephhgvrhhvvgdrtghoughinhgrsegsohhothhlihhnrdgtohhmpdhrtghpthhtoheplhhinhhugidqphifmhesvhhgvghrrdhkvghrnhgvlhdrohhrghdprhgtphhtthhopeguvghvihgtvghtrhgvvgesvhhgvghrrdhkvghrnhgvlhdrohhrghdprhgtphhtthhopehlihhnuhigqdhkvghrnhgvlhesvhhgvghrrdhkvghrnhgvlhdrohhrgh X-GND-Sasl: herve.codina@bootlin.com Content-Type: text/plain; charset="utf-8" Platforms can have a standardized connector/expansion slot that exposes signals like PWMs to expansion boards in an SoC agnostic way. The support for nexus node [1] has been added to handle those cases in commit bd6f2fd5a1d5 ("of: Support parsing phandle argument lists through a nexus node"). This commit introduced of_parse_phandle_with_args_map() to handle nexus nodes in a generic way and the gpio subsystem adopted the support in commit c11e6f0f04db ("gpio: Support gpio nexus dt bindings"). A nexus node allows to remap a phandle list in a consumer node through a connector node in a generic way. With this remapping supported, the consumer node needs to knwow only about the nexus node. Resources behind the nexus node are decoupled by the nexus node itself. This is particularly useful when this consumer is described in a device-tree overlay. Indeed, to have the exact same overlay reused with several base systems the overlay needs to known only about the connector is going to be applied to without any knowledge of the SoC (or the component providing the resource) available in the system. As an example, suppose 3 PWMs connected to a connector. The connector PWM 0 and 2 comes from the PWM 1 and 3 of the pwm-controller1. The connector PWM 1 comes from the PWM 4 of the pwm-controller2. An expansion device is connected to the connector and uses the connector PMW 1. Nexus node support in PWM allows the following description: soc { soc_pwm1: pwm-controller1 { #pwm-cells =3D <3>; }; soc_pwm2: pwm-controller2 { #pwm-cells =3D <3>; }; }; connector: connector { #pwm-cells =3D <3>; pwm-map =3D <0 0 0 &soc_pwm1 1 0 0>, <1 0 0 &soc_pwm2 4 0 0>, <2 0 0 &soc_pwm1 3 0 0>; pwm-map-mask =3D <0xffffffff 0x0 0x0>; pwm-map-pass-thru =3D <0x0 0xffffffff 0xffffffff>; }; expansion_device { pwms =3D <&connector 1 57000 0>; }; From the expansion device point of view, the PWM requested is the PWM 1 available at the connector regardless of the exact PWM wired to this connector PWM 1. Thanks to nexus node remapping described at connector node, this PWM is the PWM 4 of the pwm-controller2. The nexus node remapping handling consists in handling #pwm-cells, pwm-map, pwm-map-mask and pwm-map-pass-thru properties. This is already supported by of_parse_phandle_with_args_map() thanks to its stem_name parameter. Add support for nexus node device-tree binding and the related remapping in the PWM subsystem by simply using of_parse_phandle_with_args_map() instead of of_parse_phandle_with_args(). [1] https://github.com/devicetree-org/devicetree-specification/blob/v0.4/so= urce/chapter2-devicetree-basics.rst#nexus-nodes-and-specifier-mapping Signed-off-by: Herve Codina --- drivers/pwm/core.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index ccd54c089bab..a4eedf09922d 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -1716,8 +1716,7 @@ static struct pwm_device *of_pwm_get(struct device *d= ev, struct device_node *np, return ERR_PTR(index); } =20 - err =3D of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index, - &args); + err =3D of_parse_phandle_with_args_map(np, "pwms", "pwm", index, &args); if (err) { pr_err("%s(): can't parse \"pwms\" property\n", __func__); return ERR_PTR(err); --=20 2.47.1