From patchwork Thu Mar 30 07:12:02 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Conor Dooley X-Patchwork-Id: 13193486 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DD12AC6FD1D for ; Thu, 30 Mar 2023 07:13:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-ID:Date:Subject:CC :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=/6n4nvDpMVZtxxC34JBF7uToOWXCKcBN9nKuW8LBdQU=; b=Nw3y3zBvJ+9DZf 7yShQBFMOQsJJ2Ikea48tUf50RtKwZZU5t66HkB5KGPp40PAxDmR0gae81eFwBJgKlfaRi90qAGJ1 mGpbqK0jheBWfssNMjTzUIphyfEJvzlxWwmVQVCW7NZIKa3yALgwcO+nM9V3n1jzsqGTHCd6oRMl5 /dpCidNOLZXVyS8mdOKJI3EAOLFibnByS5Vs3U5/efNsPJwg3BeRAgPORMc4vrhaAy4Hdy5aoIf75 1BKhR/VCYWsQvptC1GcqfiSAGV2ftMC0j2M5Gx2Xd3Kv/ZQyC1iHCpsnPk+9vEKdbtM31QOhP4zM0 vex/gj8/ewkk7RBkbeOQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1phmT1-002rz1-39; Thu, 30 Mar 2023 07:13:03 +0000 Received: from esa.microchip.iphmx.com ([68.232.154.123]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1phmSy-002ruq-0k for linux-riscv@lists.infradead.org; Thu, 30 Mar 2023 07:13:01 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1680160380; x=1711696380; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=Yhc7Flvtw7DygHF2DgeNSHPYJ8ZzS+g4efc4mrx+3WI=; b=Xy4NJYwG2SZzCRGdH5FI+6wG3sxmltPUonzvryHRADPCBIdrOeesGOrX Kqb2XUyLWLCMq3eoOT+uin122kng8q0hCXmMIydDU3LBfD8IQEknnYzwH ATYylrsT0u4VTftavQ5/SiYbijZCz3BStrK5/lMdSJ3bJlJCKsCi5ct41 gIrc8ZlNJukOShHKht51HM4Qe4kVVjmDODSjTIjyVSI9a7OwxddVcDHaH Z8cIqoG/ikJgC7iFPckQ6CxTxbDcNR/uF7rRyXslkjBS0HiLp7U6Y+HtK hkoq1PjNpO/q2nW3UST9O4YC4TavNyw5tZyDvB/AnD42y61vtpNAO/ZIa A==; X-IronPort-AV: E=Sophos;i="5.98,303,1673938800"; d="scan'208";a="144635864" Received: from unknown (HELO email.microchip.com) ([170.129.1.10]) by esa6.microchip.iphmx.com with ESMTP/TLS/AES256-SHA256; 30 Mar 2023 00:12:37 -0700 Received: from chn-vm-ex01.mchp-main.com (10.10.85.143) by chn-vm-ex02.mchp-main.com (10.10.85.144) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.21; Thu, 30 Mar 2023 00:12:35 -0700 Received: from wendy.microchip.com (10.10.115.15) by chn-vm-ex01.mchp-main.com (10.10.85.143) with Microsoft SMTP Server id 15.1.2507.21 via Frontend Transport; Thu, 30 Mar 2023 00:12:34 -0700 From: Conor Dooley To: Thierry Reding , =?utf-8?q?Uwe_Kleine-K=C3=B6n?= =?utf-8?q?ig?= CC: Daire McNamara , , , , Conor Dooley Subject: [PATCH v15 0/2] Microchip Soft IP corePWM driver Date: Thu, 30 Mar 2023 08:12:02 +0100 Message-ID: <20230330071203.286972-1-conor.dooley@microchip.com> X-Mailer: git-send-email 2.39.2 MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=5109; i=conor.dooley@microchip.com; h=from:subject; bh=Yhc7Flvtw7DygHF2DgeNSHPYJ8ZzS+g4efc4mrx+3WI=; b=owGbwMvMwCFWscWwfUFT0iXG02pJDCmqZs7M+sffl+YqNccp2R9ZWMzUv3TuQmXmXzJzchwy3EO5 rrJ1lLIwiHEwyIopsiTe7muRWv/HZYdzz1uYOaxMIEMYuDgFYCI9Zxn+Cofu3t5W8nyKp8Lytj9XAg 8qNYatvmn7PH3F8WXzXoUXVTAyXKo8NTnDNym99USnUvubO73bHQ3P3Qh1/nA9ov2E5KF6PgA= X-Developer-Key: i=conor.dooley@microchip.com; a=openpgp; fpr=F9ECA03CF54F12CD01F1655722E2C55B37CF380C X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230330_001300_299322_93DE2316 X-CRM114-Status: GOOD ( 26.90 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org Hey Uwe, all, Uwe & I had a long back and forth about period calculations on v13, my ultimate conclusion being that, after some testing of the "corrected" calculation in hardware, the original calculation was correct. I think we had gotten sucked into discussion the calculation of the period itself, when we were in fact trying to calculate a bound on the period instead. That discussion is here: https://lore.kernel.org/linux-pwm/Y+ow8tfAHo1yv1XL@wendy/ There was, of course, another chat about the niche bits of this calculation on v14 too: https://lore.kernel.org/linux-pwm/20230322105536.kgt3ffowefqlg6eu@pengutronix.de/ Thanks, Conor. Changes since v14: - change period_steps calculation logic to correctly handle the cases where tmp % (254 + 1) == 0, by swapping implicit truncation for explicit rounding upwards and subtracting zero - special case periods < 1/clk_rate & add a note in limitations about this, although I think this issue wasn't present prior to v15's changes - check for smaller suitable values of prescale, which picks the "more correct" value in about half of all cases, particularly those where tmp is large. - explain what I mean by the "optimal" values for prescale/period steps re-fix use of defines - add a comment about how sync_upd mode works - make the use of period_steps and prescale consistently refer to the register values rather than, in comments, using these to mean the resulting values after 1 has been added - drop the PREG_TO_VAL() macro, as most of its users are now gone & it only added to the register value versus "real" value problem - report pwmchip_add() failures Changes since v13: - couple bits of cleanup to apply_locked(), suggested by Uwe - move the overhead waiting for a change to be applied, for channels with shadow registers, to subsequent calls to apply(). This has the benefit of only waiting when two calls to apply() are close in time rather than eating the delay in every call. Changes since v11: - swap a "bare" multiply & divide for the corresponding helper to prevent overflow - factor out duplicate clk rate acquisition & period calculation - make the period calculation return void by checking the validity of the clock rate in the caller - drop the binding & dt patch, they're on-track for v6.2 via my tree Changes since v10: - reword some comments - try to assign the period if a disable is requested - drop a cast around a u8 -> u16 conversion - fix a check on period_steps that should be on the hw_ variant - split up the period calculation in get_state() to fix the result on 32 bit - add a rate variable in get_state() to only call get_rate() once - redo the locking as suggested to make it more straightforward. - stop checking for enablement in get_state() that was working around intended behaviour of the sysfs interface Changes since v9: - fixed the missing unlock that Dan reported Changes since v8: - fixed a(nother) raw 64 bit division (& built it for riscv32!) - added a check to make sure we don't try to sleep for 0 us Changes since v7: - rebased on 6.0-rc1 - reworded comments you highlighted in v7 - fixed the overkill sleeping - removed the unused variables in calc_duty - added some extra comments to explain behaviours you questioned in v7 - make the mutexes un-interruptible - fixed added the 1s you suggested for the if(period_locked) logic - added setup of the channel_enabled shadowing - fixed the period reporting for the negedge == posedge case in get_state() I had to add the enabled check, as otherwise it broke setting the period for the first time out of reset. - added a test for invalid PERIOD_STEPS values, in which case we abort if we cannot fix the period Changes from v6: - Dropped an unused variable that I'd missed - Actually check the return values of the mutex lock()s - Re-rebased on -next for the MAINTAINERS patch (again...) Changes from v5: - switched to a mutex b/c we must sleep with the lock taken - simplified the locking in apply() and added locking to get_state() - reworked apply() as requested - removed the loop in the period calculation (thanks Uwe!) - add a copy of the enable registers in the driver to save on reads. - remove the second (useless) write to sync_update - added some missing rounding in get_state() - couple other minor cleanups as requested in: https://lore.kernel.org/linux-riscv/20220709160206.cw5luo7kxdshoiua@pengutronix.de/ Changes from v4: - dropped some accidentally added files Changes before v4: https://lore.kernel.org/linux-pwm/20220721172109.941900-1-mail@conchuod.ie Conor Dooley (2): pwm: add microchip soft ip corePWM driver MAINTAINERS: add pwm to PolarFire SoC entry MAINTAINERS | 1 + drivers/pwm/Kconfig | 10 + drivers/pwm/Makefile | 1 + drivers/pwm/pwm-microchip-core.c | 507 +++++++++++++++++++++++++++++++ 4 files changed, 519 insertions(+) create mode 100644 drivers/pwm/pwm-microchip-core.c