From patchwork Fri Dec 11 16:47:49 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nicolas Saenz Julienne X-Patchwork-Id: 11968641 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5FD89C4167B for ; Fri, 11 Dec 2020 16:50:12 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 16A512310E for ; Fri, 11 Dec 2020 16:50:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 16A512310E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:Message-Id:Date:Subject:To:From: Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender :Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=oXPJRgJS/BnzVN16icWNcpHnLY4MpL5n+fhfcYoTFPY=; b=0bIDd5ezqyTH6M059VlbPDizoZ tJhwd3ipZEBs8EIItpS89jksG5ewwREvTWC1JLG1WQRRI0mVpKzyx+JMDF+B7FVpjlJu0wKT/7773 iaVrFfeYCbLCnCjigz/7XCczirb270kcpe8cmKRsKLBlpfbFxw/p9Kddyf2gZACOzEy5yvKaydTV2 VszOF2XSVGLJbqSVSLL1qhj/MqobwDjlcsop6KtKRrkhdDlXbkCHHzU2ceyUWKUGl4YXE20BGpXWS yo34gNe3pxlbx+2+okDl204pUtpQBO+IDSY/985i2Z5uefeHfUDNd7pblHU5LYGEy/X/kC2SHt+9T s11MR/WA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1knlav-0008W1-AW; Fri, 11 Dec 2020 16:48:37 +0000 Received: from mx2.suse.de ([195.135.220.15]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1knlaV-0008Mz-Bo; Fri, 11 Dec 2020 16:48:18 +0000 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id B06C2ADCD; Fri, 11 Dec 2020 16:48:07 +0000 (UTC) From: Nicolas Saenz Julienne To: u.kleine-koenig@pengutronix.de, linux-kernel@vger.kernel.org Subject: [PATCH v6 00/11] Raspberry Pi PoE HAT fan support Date: Fri, 11 Dec 2020 17:47:49 +0100 Message-Id: <20201211164801.7838-1-nsaenzjulienne@suse.de> X-Mailer: git-send-email 2.29.2 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201211_114811_626032_48B4D66F X-CRM114-Status: GOOD ( 24.47 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devel@driverdev.osuosl.org, linux-pwm@vger.kernel.org, f.fainelli@gmail.com, devicetree@vger.kernel.org, sboyd@kernel.org, gregkh@linuxfoundation.org, linus.walleij@linaro.org, dmitry.torokhov@gmail.com, Eric Anholt , linux-gpio@vger.kernel.org, andy.shevchenko@gmail.com, bcm-kernel-feedback-list@broadcom.com, wahrenst@gmx.net, p.zabel@pengutronix.de, linux-input@vger.kernel.org, Nicolas Saenz Julienne , bgolaszewski@baylibre.com, linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rpi-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org The aim of this series is to add support to the fan found on RPi's PoE HAT. Some commentary on the design can be found below. But the imporant part to the people CC'd here not involved with PWM is that, in order to achieve this properly, we also have to fix the firmware interface the driver uses to communicate with the PWM bus (and many other low level functions). Specifically, we have to make sure the firmware interface isn't unbound while consumers are still up. So, patch #1 & #2 introduce reference counting in the firwmware interface driver and patches #3 to #8 update all firmware users. Patches #9 to #11 introduce the new PWM driver. I sent everything as a single series as the final version of the PWM drivers depends on the firwmare fixes, but I'll be happy to split this into two separate series if you think it's better. --- Original cover letter below --- This series aims at adding support to RPi's official PoE HAT fan[1]. The HW setup is the following: | Raspberry Pi | PoE HAT | arm core -> Mailbox -> RPi co-processor -> I2C -> Atmel MCU -> PWM -> FAN The arm cores have only access to the mailbox interface, as i2c0, even if physically accessible, is to be used solely by the co-processor (VideoCore 4/6). This series implements a PWM bus, and has pwm-fan sitting on top of it as per this discussion: https://lkml.org/lkml/2018/9/2/486. Although this design has a series of shortcomings: - It depends on a DT binding: it's not flexible if a new hat shows up with new functionality, we're not 100% sure we'll be able to expand it without breaking backwards compatibility. But without it we can't make use of DT thermal-zones, which IMO is overkill. - We're using pwm-fan, writing a hwmon driver would, again, give us more flexibility, but it's not really needed at the moment. I personally think that it's not worth the effort, it's unlikely we'll get things right in advance. And ultimately, if the RPi people come up with something new, we can always write a new driver/bindings from scratch (as in not reusing previous code). That said, I'm more than happy to change things if there is a consensus that another design will do the trick. [1] https://www.raspberrypi.org/blog/introducing-power-over-ethernet-poe-hat/ --- Changes since v5: - Small cleanups - Add extra code comments Changes since v4: - Cleanup devm calls - Rename compatible string so it's unique to the PoE HAT Changes since v3: - Split first patch, #1 introduces refcount, then #2 the devm function - Fix touchscreen function - Use kref Changes since v2: - Introduce devm_rpi_firmware_get() - Small cleanups in PWM driver Changes since v1: - Address PWM driver changes - Fix binding, now with 2 cells Nicolas Saenz Julienne (11): firmware: raspberrypi: Keep count of all consumers firmware: raspberrypi: Introduce devm_rpi_firmware_get() clk: bcm: rpi: Release firmware handle on unbind gpio: raspberrypi-exp: Release firmware handle on unbind reset: raspberrypi: Release firmware handle on unbind soc: bcm: raspberrypi-power: Release firmware handle on unbind staging: vchiq: Release firmware handle on unbind input: raspberrypi-ts: Release firmware handle when not needed dt-bindings: pwm: Add binding for RPi firmware PWM bus DO NOT MERGE: ARM: dts: Add RPi's official PoE hat support pwm: Add Raspberry Pi Firmware based PWM bus .../arm/bcm/raspberrypi,bcm2835-firmware.yaml | 20 ++ arch/arm/boot/dts/bcm2711-rpi-4-b.dts | 54 +++++ drivers/clk/bcm/clk-raspberrypi.c | 2 +- drivers/firmware/raspberrypi.c | 69 +++++- drivers/gpio/gpio-raspberrypi-exp.c | 2 +- drivers/input/touchscreen/raspberrypi-ts.c | 2 +- drivers/pwm/Kconfig | 9 + drivers/pwm/Makefile | 1 + drivers/pwm/pwm-raspberrypi-poe.c | 216 ++++++++++++++++++ drivers/reset/reset-raspberrypi.c | 2 +- drivers/soc/bcm/raspberrypi-power.c | 2 +- .../interface/vchiq_arm/vchiq_arm.c | 2 +- .../pwm/raspberrypi,firmware-poe-pwm.h | 13 ++ include/soc/bcm2835/raspberrypi-firmware.h | 10 + 14 files changed, 395 insertions(+), 9 deletions(-) create mode 100644 drivers/pwm/pwm-raspberrypi-poe.c create mode 100644 include/dt-bindings/pwm/raspberrypi,firmware-poe-pwm.h