From mboxrd@z Thu Jan 1 00:00:00 1970 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 EAFB4C433FE for ; Fri, 30 Sep 2022 13:50:01 +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:In-Reply-To:MIME-Version:References: Message-ID:Subject:CC:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=xgPhR0Kiwv/OBFiK6vC6yL+BYdLVUZahOoFSi5aRi8U=; b=2DT3R4cpgd2Gms HYP+wLtCQAACwgj/elnN5X9XoYNmu5k/SG6qmeexXql3GEDgqLgZ6g7Hte/T1276OJoyM+Sqp/zhw bK+xPqpBi6dBFQOpVfwRT060xdYQ8+Z6ZnkeYD8M8b6z7v1gruCephZFKNs2RuX453RarnmkHCRoW 296yACq+nEUzDmNAKBvDFe4yJBr0Z5SFoNWT6JEg0mnGY3lHRVSVSLU+pf7G3+645asvhpVzivoj3 KWfH8qzmc1qNtENFrFvVMRq06lbWK2NgiURSrxiftqtCraGcLhrRJvsCt7ekJRVRwlfcQ9ulSIrFl KqAAK6jX30Bdry4OyAlQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oeGOm-009U0X-DK; Fri, 30 Sep 2022 13:49:52 +0000 Received: from esa.microchip.iphmx.com ([68.232.154.123]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1oeGOj-009Tz6-A0 for linux-riscv@lists.infradead.org; Fri, 30 Sep 2022 13:49:51 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1664545789; x=1696081789; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=n9ebYPlj7qybcpG08KXmsqxmGM43O0sG2jH9VygklZk=; b=XXhz7gJ2RNpV0AVGSfbMS2rh2WaFa2yvORh04F1LpWyqE8o5Uh85sRQH CLYv/7zKsrvJtkTVPHgyOvKZD4musCJjuwx8KvWC6677RyEwA3dzS5wEA QCvO10qrtGZqWMLpsQjaY0RWMjWY26V4JaUvlooMj1SgsFkfDcNokLTzJ TuuhaIafMkIvqkZEmJn6HBooQOi6PROzYC1kBqyuQKfzQ9iXfOoBNztdS opdocckN4UNbJRdPIpbZgZ/rCn4ENj08LOCVu4Fs3BOv9VeuFRKCUnCcI T2cxRvIi9Xxsb2JYboa0Gt10h67IwBmHJBRUZRoqboAp7qPewGukybD/Y Q==; X-IronPort-AV: E=Sophos;i="5.93,358,1654585200"; d="scan'208";a="179788492" Received: from unknown (HELO email.microchip.com) ([170.129.1.10]) by esa2.microchip.iphmx.com with ESMTP/TLS/AES256-SHA256; 30 Sep 2022 06:49:41 -0700 Received: from chn-vm-ex04.mchp-main.com (10.10.85.152) 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 15.1.2507.12; Fri, 30 Sep 2022 06:49:35 -0700 Received: from wendy (10.10.115.15) by chn-vm-ex04.mchp-main.com (10.10.85.152) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.12 via Frontend Transport; Fri, 30 Sep 2022 06:49:33 -0700 Date: Fri, 30 Sep 2022 14:49:12 +0100 From: Conor Dooley To: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= CC: Thierry Reding , Rob Herring , Krzysztof Kozlowski , Daire McNamara , , , , Subject: Re: [PATCH v10 3/4] pwm: add microchip soft ip corePWM driver Message-ID: References: <20220824091215.141577-1-conor.dooley@microchip.com> <20220824091215.141577-4-conor.dooley@microchip.com> <20220915072152.y346csakn7wetpz5@pengutronix.de> <20220919135008.sahwmwbfwvgplji4@pengutronix.de> <20220930091316.kdkf4oeu6uvxzqa6@pengutronix.de> <20220930133933.br5kanbh3clvahvr@pengutronix.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20220930133933.br5kanbh3clvahvr@pengutronix.de> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220930_064949_473625_4821D379 X-CRM114-Status: GOOD ( 29.32 ) 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: , Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On Fri, Sep 30, 2022 at 03:39:33PM +0200, Uwe Kleine-K=F6nig wrote: > On Fri, Sep 30, 2022 at 10:45:56AM +0100, Conor Dooley wrote: > > On Fri, Sep 30, 2022 at 11:13:16AM +0200, Uwe Kleine-K=F6nig wrote: > > > On Mon, Sep 19, 2022 at 03:29:19PM +0100, Conor Dooley wrote: > > > > Hey Uwe, > > > > = > > > > On Mon, Sep 19, 2022 at 03:50:08PM +0200, Uwe Kleine-K=F6nig wrote: > > > > > On Mon, Sep 19, 2022 at 01:53:56PM +0100, Conor Dooley wrote: > > > > > > Because I was running into conflicts between the reporting here= and some > > > > > > of the checks that I have added to prevent the PWM being put in= to an > > > > > > invalid state. On boot both negedge and posedge will be zero & = this was > > > > > > preventing me from setting the period at all. > > > > > = > > > > > I don't understood that. > > > > = > > > > On startup, (negedge =3D=3D posedge) is true as both are zero, but = the reset > > > > values for prescale and period are actually 0x8. If on reset I try = to > > > > set a small period, say "echo 1000 > period" apply() returns -EINVAL > > > > because of a check in the pwm core in pwm_apply_state() as I am > > > > attempting to set the period to lower than the out-of-reset duty cy= cle. > > > = > > > You're supposed to keep the period for pwm#1 untouched while configur= ing > > > pwm#0 only if pwm#1 already has a consumer. So if pwm#1 isn't request= ed, > > > you can change the period for pwm#0. > > = > > I must have done a bad job of explaining here, as I don't think this is > > an answer to my question. > > = > > On reset, the prescale and period_steps registers are set to 0x8. If I > > attempt to set the period to do "echo 1000 > period", I get -EINVAL back > > from pwm_apply_state() (in next-20220928 it's @ L562 in pwm/core.c) as > > the duty cycle is computed as twice the period as, on reset, we have > > posedge =3D negedge =3D 0x0. The check of state->duty_cycle > state->pe= riod > > fails in pwm_apply_state() as a result. > = > So set duty_cycle to 0 first? > = > A problem of the sysfs interface is that you can only set one parameter > after the other. So there you have to find a sequence of valid > pwm_states that only differ in a single parameter between the initial > and the desired state. > = > That's nothing a "normal" pwm consumer would be affected by. (IMHO we > should have a userspace API that benefits from the properties of > pwm_apply().) Right, so I guess I will drop the check so. That's good to know, thanks. Would you rather I waited until after the mw to send v11? Thanks, Conor. _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv