From patchwork Thu Jun 6 14:50:54 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Thomas_Wei=C3=9Fschuh?= X-Patchwork-Id: 802224 Received: from todd.t-8ch.de (todd.t-8ch.de [159.69.126.157]) (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 9E9661A2544; Thu, 6 Jun 2024 14:51:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=159.69.126.157 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717685467; cv=none; b=Vjji2MktD9UQrnoxPEUOUhbSZZ6fOn76p0y9hVjT4X2dDaVtkCwbdU0AgC35VZUBmawuYEW0ND6p3SFwd9Oi++OW9j9ltpBmX3Fqs4wAxq45X3KgNSRSKvOdaGAX1FSRV/tJDbhzo4hivYC918f+QH2mtyp7ZGjT5qIb9YVJANo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717685467; c=relaxed/simple; bh=bdXFxi8tnEgbfjdU5btF0ytSOB3GTwGldFvQDL6lPaU=; h=From:Subject:Date:Message-Id:MIME-Version:Content-Type:To:Cc; b=XbfUdi38O/S/Tz27749PqBV9mFVu02/Stqj9cgzzuLX1DgCGpVyBGieQ8EUnPUPiSrZz2sLFzfPVDLBhKtijrN3DlZW0HntVCdTXUI8dGXUOx74yc1Osq+Ho74rfxkWjRjJX1XN8a51BgHOXw+WEQ1EsrUWrRjV/L05Q+8uFxC4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=weissschuh.net; spf=pass smtp.mailfrom=weissschuh.net; dkim=pass (1024-bit key) header.d=weissschuh.net header.i=@weissschuh.net header.b=ECxqKI+m; arc=none smtp.client-ip=159.69.126.157 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=weissschuh.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=weissschuh.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=weissschuh.net header.i=@weissschuh.net header.b="ECxqKI+m" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=weissschuh.net; s=mail; t=1717685463; bh=bdXFxi8tnEgbfjdU5btF0ytSOB3GTwGldFvQDL6lPaU=; h=From:Subject:Date:To:Cc:From; b=ECxqKI+mk0WDSHshu3UnOyOOpTrdOykq2TzeANMawHE4o9iHVz+meClLJTAxcQhBi X+HVbqZzB892lJhHedLw8sucAbvM6FpF7CJQGugMyJnlqTOMayU7XBUm5LcT7zKWO4 i8bHz1OwzW4AGeFz51gVXOA2s08XQTWHzq+L86m0= From: =?utf-8?q?Thomas_Wei=C3=9Fschuh?= Subject: [PATCH RFC 0/6] power: supply: extension API Date: Thu, 06 Jun 2024 16:50:54 +0200 Message-Id: <20240606-power-supply-extensions-v1-0-b45669290bdc@weissschuh.net> Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-B4-Tracking: v=1; b=H4sIAM7MYWYC/6tWKk4tykwtVrJSqFYqSi3LLM7MzwNyDHUUlJIzE vPSU3UzU4B8JSMDIxMDMwMj3YL88tQi3eLSgoKcSt3UipLUPJCWYl0D8xRLE8s0UwPLFEsloO6 CotS0zAqwydFKQW7OSrG1tQBcwKYubgAAAA== To: Sebastian Reichel , Jeremy Soller , System76 Product Development , Hans de Goede , =?utf-8?q?Ilpo_J=C3=A4rvinen?= Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, platform-driver-x86@vger.kernel.org, =?utf-8?q?Thomas_Wei=C3=9Fschuh?= X-Mailer: b4 0.13.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1717685463; l=3433; i=linux@weissschuh.net; s=20221212; h=from:subject:message-id; bh=bdXFxi8tnEgbfjdU5btF0ytSOB3GTwGldFvQDL6lPaU=; b=AxoBqHX/LVFjRTc3+iH+Ep8JhFgtL3uiKsc7KN6uCaTsZjrAigmZ7ItvJJaYeMVpK36qytGBy 8BzYFJ520I1BqEvWgqXunFdUcKUQNM2NKwzvUqIHeknJpeSxPMOqpkf X-Developer-Key: i=linux@weissschuh.net; a=ed25519; pk=KcycQgFPX2wGR5azS7RhpBqedglOZVgRPfdFSPB1LNw= Introduce a mechanism for drivers to extend the properties implemented by a power supply. Motivation ---------- Various drivers, mostly in platform/x86 extend the ACPI battery driver with additional sysfs attributes to implement more UAPIs than are exposed through ACPI by using various side-channels, like WMI, nonstandard ACPI or EC communication. While the created sysfs attributes look similar to the attributes provided by the powersupply core, there are various deficiencies: * They don't show up in uevent payload. * They can't be queried with the standard in-kernel APIs. * They don't work with triggers. * The extending driver has to reimplement all of the parsing, formatting and sysfs display logic. * Writing a extension driver is completely different from writing a normal power supply driver. * Properties can not be properly overriden. The proposed extension API avoids all of these issues. An extension is just a "struct power_supply_ext" with the same kind of callbacks as in a normal "struct power_supply_desc". The API is meant to be used via battery_hook_register(), the same way as the current extensions. For example my upcoming cros_ec charge control driver[0] saves 80 lines of code with this patchset. Contents -------- * Patch 1 and 2 are generic preparation patches, that probably make sense without this series. * Patch 3 implements the extension API itself. * Patch 4 implements a PoC locking scheme for the extension API. * Patch 5 adds extension support to test_power.c * Patch 6 converts the in-tree platform/x86/system76 driver to the extension API. Open issues ----------- * Newly registered properties will not show up in hwmon. To do that properly would require some changes in the hwmon core. As far as I know, no current driver would extend the hwmon properties anyways. * As this is only useful with the hooks of CONFIG_ACPI_BATTERY, should it also be gated behind this or another config? * Only one extension can be used at a time. So far this should be enough, having more would complicate the implementation. * Is an rw_semaphore acceptable? [0] https://lore.kernel.org/lkml/20240528-cros_ec-charge-control-v2-0-81fb27e1cff4@weissschuh.net/ Signed-off-by: Thomas Weißschuh --- Thomas Weißschuh (6): power: supply: sysfs: use power_supply_property_is_writeable() power: supply: core: avoid iterating properties directly power: supply: core: implement extension API power: supply: core: add locking around extension access power: supply: test-power: implement a power supply extension platform/x86: system76: Use power_supply extension API drivers/platform/x86/system76_acpi.c | 83 +++++++++--------- drivers/power/supply/power_supply.h | 9 ++ drivers/power/supply/power_supply_core.c | 136 ++++++++++++++++++++++++++++-- drivers/power/supply/power_supply_hwmon.c | 48 +++++------ drivers/power/supply/power_supply_sysfs.c | 39 ++++++--- drivers/power/supply/test_power.c | 102 ++++++++++++++++++++++ include/linux/power_supply.h | 25 ++++++ 7 files changed, 357 insertions(+), 85 deletions(-) --- base-commit: 2df0193e62cf887f373995fb8a91068562784adc change-id: 20240602-power-supply-extensions-07d949f509d9 Best regards,