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 CB97FCCD1AB for ; Wed, 22 Oct 2025 11:35:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=yO34qPsn7QHCTVDfDKcQas0jsSh3wLko8YufcBfx8as=; b=JzG9Kefcs2yi5pZTtWlSwPkNu6 /w3USL7AZEgk8qpDyOn/2zXISzq25fzNjH/rRoaDZw53+IUgDCTeGQMugcL66VsrN3dVpbEJU701g 3Ffxr9VY/LhZWMNEPqfwp2rERFMn06ZmI3uPS6wQgnfkLwLiC/amqHB4uVltgdFA0UiQGMHNTO17I qZx5Rd+FRq3ZGx1Tf6MmQs1hpwZGv3Woaa+VgobKB4uu+e1YNASROFE5+MQIHnKcMfg6W9CqTpo/9 nZRbvr5kAYr8TbmcnZGDvTA/1J2pg8K/zZnOFlbg9joCCOXJa5cNKPcg4VZGIxAb4Ql8dneukuncn UlyM3uXw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vBX7Y-00000002fVM-2FND; Wed, 22 Oct 2025 11:35:12 +0000 Received: from mail-ej1-x633.google.com ([2a00:1450:4864:20::633]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vBX7Q-00000002fRD-2g7X for linux-arm-kernel@lists.infradead.org; Wed, 22 Oct 2025 11:35:07 +0000 Received: by mail-ej1-x633.google.com with SMTP id a640c23a62f3a-b5e19810703so1098919266b.2 for ; Wed, 22 Oct 2025 04:35:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1761132903; x=1761737703; darn=lists.infradead.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=yO34qPsn7QHCTVDfDKcQas0jsSh3wLko8YufcBfx8as=; b=PrQ5zmIjkbY9LjbceJEt+mxQ+/cBFuwUzKZl9iYPm6tzBDUQbCHt5IxC7WJ5M5XtFj DnsuPDin1zMGfz0jvMeIDGLQgSF6RGTpY1bnJMmAls+sCt/UvwjCjimPdTCJrTOR0HQB lOZDXicFvFXYo8tR9VVzmj6e/1J4+PSOWco1lt9CXYozzvlMp421Fl4L+wy8xj+8VG4Q 0Lb7hW0uXqtw8WkZSwYUZ0U0YS5c1z0Yr7SPz5YZ8FOCri/3ypDQI/aE3wsyZKznQ9Zr LufTBlSR3su0ItAL6sSRQcgwu0CE1sFOHGAn6Vqte9JtAXzL/M+NYcZbvoIl3Qo33I2J rVCg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1761132903; x=1761737703; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=yO34qPsn7QHCTVDfDKcQas0jsSh3wLko8YufcBfx8as=; b=m42cyUbfKi9FOVZf4BuhoyKDbXwfjl1LC7Ancr+bZ/D0RL1enTu+DA9udNoUknOs0p zBG15mnyGwmNiLwY/kWUnoDv1Lfrl+7Mn637hoUxP/2MtA+EgbjypcDmwOcVtKo39qeV XKgHmtHj1rzosWnQmFA1xfB+/Pf7ryI5LVt05AgCrPUVmdq4pXCX1gbGGEomQaWQrrpN 1OKT875oSnM7ldjyBRoU4taIy9L7l2hZKNNVGtjBtgWIaPtAGMMprUU4A7QDtEP00iVI kL0JHZvhO9iK287crppm0iBuOHJxguOHIH838E/ObS+1tkNZUYigcz4UtNAXfhhJBKjR WRig== X-Forwarded-Encrypted: i=1; AJvYcCXqOd3LaU7qDmn6O0swK1OzBsJ/dnXY9/iwGfS6SxJ1ohhRaIFovg2F7HYjXWNikYr9BZlXuWwJEcDlgxtd1F4s@lists.infradead.org X-Gm-Message-State: AOJu0YyQYxH/XD6/rLvFzH9iWGBNY7TKT/GTGOU6fem5KlmIHeoXBq+n i+jLvFMa5YS5UR900CV4E/uWQXNfdKtFkccEf3u8UCYDwn/Vxp1w4kLE X-Gm-Gg: ASbGncsZMGnCvBcpmUwmyFoD/f1bV5LZxvQfUK2beXfgSBedydOGkAKzjuGEXOBy7rf aWaR6EDfrdQMhIe4UXFIUL9S2nNNke5KgeRebOTpv3InSR8DUDWIfGR9TRH+0uI3yTCxdqguY3p On/yOBkVWpOJ99QNgwYdCibzohbh+aMC1NzSXWW730EgeN/eIMRg3F3JaJt4tSjqKc+gYuvQHtg vH9tDjrTJnyGEfq5pHjTfZQNekCbkRIVUQnzHqcSeZ94ckhhxh1d1vTacIDRGJPxEsLLQzdzAkK KKdZnx1A0Nh7JQchz6FLgIOT4UNEr9nJ9KEyzno+e2R9sdSIQmNk3+Eo/fj60t0oTPmJ3TiMjr2 WCVcS+inEpMEyWiKgrBolxrdAl/xFOZmdYYCwre9EqyOuSj9uARQPCVYFG+woiF/LiWXCEu7A/u QMtrA3DYwgpQJZvw/rEfxL+4rBzrovJOIlx8QKxhkCt/A= X-Google-Smtp-Source: AGHT+IHfqiWBy7zfGoCqLQpI11jm6dwQ/WE7NiaPb8Gr8GzjB9HYaKJgVjiXf/jFs4wJwPRiCS9gYA== X-Received: by 2002:a17:907:1c82:b0:b4e:a47f:715d with SMTP id a640c23a62f3a-b6472a6a145mr2430377866b.17.1761132902443; Wed, 22 Oct 2025 04:35:02 -0700 (PDT) Received: from [10.25.209.134] ([128.77.115.157]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-b65ebb4dcf2sm1303250766b.75.2025.10.22.04.35.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 22 Oct 2025 04:35:02 -0700 (PDT) Message-ID: <804dd1f5-7e79-4bfa-b777-c97bb89a713a@gmail.com> Date: Wed, 22 Oct 2025 04:35:00 -0700 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 5/8] reset: imx8mp-audiomix: Switch to using regmap API To: Frank Li Cc: Abel Vesa , Peng Fan , Michael Turquette , Stephen Boyd , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Shawn Guo , Fabio Estevam , Philipp Zabel , Daniel Baluta , Shengjiu Wang , linux-clk@vger.kernel.org, imx@lists.linux.dev, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Pengutronix Kernel Team References: <20251017112025.11997-1-laurentiumihalcea111@gmail.com> <20251017112025.11997-6-laurentiumihalcea111@gmail.com> Content-Language: en-US From: Laurentiu Mihalcea In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251022_043504_748930_3BE42947 X-CRM114-Status: GOOD ( 32.00 ) X-BeenThere: linux-arm-kernel@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-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 10/17/2025 7:49 AM, Frank Li wrote: > On Fri, Oct 17, 2025 at 04:20:22AM -0700, Laurentiu Mihalcea wrote: >> From: Laurentiu Mihalcea >> >> As far as the Linux kernel is concerned, block devices such as i.MX8MP's >> AUDIOMIX block control or i.MX8ULP's SIM LPAV can simultaneously act as >> clock controllers, reset controllers or mux controllers. Since these IPs >> offer different functionalities through different subsystem APIs, it's >> important to make sure that the register R-M-W cycles are performed under >> the same lock across all subsystem APIs. This will ensure that registers >> will not end up with the wrong values because of race conditions (e.g. >> clock consumer tries to update block control register A, while, at the >> same time, reset consumer tries to update the same block control register). >> >> However, the aforementioned race conditions will only impact block control >> IPs which use the same register for multiple functionalities. For example, >> i.MX8MP's AUDIOMIX block control IP provides clock gating functionalities >> and reset control functionalities through different registers. This is why >> the current approach (i.e. clock control and reset control work using >> different locks) has worked well so far. >> >> Since we want to extend this driver to be usable for i.MX8ULP's SIM LPAV >> block control IP, we need to make sure that clock control, reset control, >> and mux control APIs use the same lock since all of these functionalities >> are performed using the SYSCTRL0 register. >> >> To do so, we need to switch to the regmap API and, if possible, use the >> parent device's regmap, which, in the case of i.MX8ULP, will be the clock >> controller. This way, we can make sure that the clock gates and the reset >> controller will use the same lock to perform the register R-M-W cycles. >> >> This change will also work fine for cases where we don't really need to >> share the lock across multiple APIs (e.g. i.MX8MP's AUDIOMIX block >> control) since regmap will take care of the locking we were previously >> explicitly performing in the driver. >> >> The transition to the regmap API also involves some cleanup. Specifically, >> we can make use of devres to unmap the device's memory and get rid of the >> memory mapping-related error paths and the remove() function altogether. >> >> Signed-off-by: Laurentiu Mihalcea >> --- >> drivers/reset/reset-imx8mp-audiomix.c | 95 +++++++++++++++++---------- >> 1 file changed, 61 insertions(+), 34 deletions(-) >> >> diff --git a/drivers/reset/reset-imx8mp-audiomix.c b/drivers/reset/reset-imx8mp-audiomix.c >> index e9643365a62c..c74ce6e04177 100644 >> --- a/drivers/reset/reset-imx8mp-audiomix.c >> +++ b/drivers/reset/reset-imx8mp-audiomix.c >> @@ -11,6 +11,7 @@ >> #include >> #include >> #include >> +#include >> #include >> >> #define IMX8MP_AUDIOMIX_EARC_RESET_OFFSET 0x200 >> @@ -19,6 +20,7 @@ >> struct imx8mp_reset_map { >> unsigned int offset; >> unsigned int mask; >> + unsigned int shift; >> bool active_low; >> }; >> >> @@ -26,24 +28,27 @@ static const struct imx8mp_reset_map reset_map[] = { >> [IMX8MP_AUDIOMIX_EARC_RESET] = { >> .offset = IMX8MP_AUDIOMIX_EARC_RESET_OFFSET, >> .mask = BIT(0), >> + .shift = 0, >> .active_low = true, >> }, >> [IMX8MP_AUDIOMIX_EARC_PHY_RESET] = { >> .offset = IMX8MP_AUDIOMIX_EARC_RESET_OFFSET, >> .mask = BIT(1), >> + .shift = 1, >> .active_low = true, >> }, >> [IMX8MP_AUDIOMIX_DSP_RUNSTALL] = { >> .offset = IMX8MP_AUDIOMIX_DSP_RUNSTALL_OFFSET, >> .mask = BIT(5), >> + .shift = 5, > why need shift? you can use ffs(mask) to get shift. > >> .active_low = false, >> }, >> }; >> >> struct imx8mp_audiomix_reset { >> struct reset_controller_dev rcdev; >> - spinlock_t lock; /* protect register read-modify-write cycle */ >> void __iomem *base; >> + struct regmap *regmap; >> }; >> >> static struct imx8mp_audiomix_reset *to_imx8mp_audiomix_reset(struct reset_controller_dev *rcdev) >> @@ -55,26 +60,15 @@ static int imx8mp_audiomix_update(struct reset_controller_dev *rcdev, >> unsigned long id, bool assert) >> { >> struct imx8mp_audiomix_reset *priv = to_imx8mp_audiomix_reset(rcdev); >> - void __iomem *reg_addr = priv->base; >> - unsigned int mask, offset, active_low; >> - unsigned long reg, flags; >> + unsigned int mask, offset, active_low, shift, val; >> >> mask = reset_map[id].mask; >> offset = reset_map[id].offset; >> active_low = reset_map[id].active_low; >> + shift = reset_map[id].shift; >> + val = (active_low ^ assert) << shift; >> >> - spin_lock_irqsave(&priv->lock, flags); >> - >> - reg = readl(reg_addr + offset); >> - if (active_low ^ assert) >> - reg |= mask; >> - else >> - reg &= ~mask; >> - writel(reg, reg_addr + offset); >> - >> - spin_unlock_irqrestore(&priv->lock, flags); >> - >> - return 0; >> + return regmap_update_bits(priv->regmap, offset, mask, val); >> } >> >> static int imx8mp_audiomix_reset_assert(struct reset_controller_dev *rcdev, >> @@ -94,6 +88,50 @@ static const struct reset_control_ops imx8mp_audiomix_reset_ops = { >> .deassert = imx8mp_audiomix_reset_deassert, >> }; >> >> +static const struct regmap_config regmap_config = { >> + .reg_bits = 32, >> + .val_bits = 32, >> + .reg_stride = 4, >> +}; >> + >> +/* assumption: registered only if not using parent regmap */ >> +static void imx8mp_audiomix_reset_iounmap(void *data) >> +{ >> + struct imx8mp_audiomix_reset *priv = dev_get_drvdata(data); >> + >> + iounmap(priv->base); >> +} >> + >> +/* assumption: dev_set_drvdata() is called before this */ >> +static int imx8mp_audiomix_reset_get_regmap(struct device *dev) >> +{ >> + struct imx8mp_audiomix_reset *priv; >> + int ret; >> + >> + priv = dev_get_drvdata(dev); >> + >> + /* try to use the parent's regmap */ >> + priv->regmap = dev_get_regmap(dev->parent, NULL); >> + if (priv->regmap) >> + return 0; >> + >> + /* ... if that's not possible then initialize the regmap right now */ >> + priv->base = of_iomap(dev->parent->of_node, 0); >> + if (!priv->base) >> + return dev_err_probe(dev, -ENOMEM, "failed to iomap address space\n"); >> + >> + ret = devm_add_action_or_reset(dev, imx8mp_audiomix_reset_iounmap, dev); >> + if (ret) >> + return dev_err_probe(dev, ret, "failed to register action\n"); >> + >> + priv->regmap = devm_regmap_init_mmio(dev, priv->base, ®map_config); >> + if (IS_ERR(priv->regmap)) >> + return dev_err_probe(dev, PTR_ERR(priv->regmap), >> + "failed to initialize regmap\n"); >> + >> + return 0; >> +} >> + >> static int imx8mp_audiomix_reset_probe(struct auxiliary_device *adev, >> const struct auxiliary_device_id *id) >> { >> @@ -105,36 +143,26 @@ static int imx8mp_audiomix_reset_probe(struct auxiliary_device *adev, >> if (!priv) >> return -ENOMEM; >> >> - spin_lock_init(&priv->lock); >> - >> priv->rcdev.owner = THIS_MODULE; >> priv->rcdev.nr_resets = ARRAY_SIZE(reset_map); >> priv->rcdev.ops = &imx8mp_audiomix_reset_ops; >> priv->rcdev.of_node = dev->parent->of_node; >> priv->rcdev.dev = dev; >> priv->rcdev.of_reset_n_cells = 1; >> - priv->base = of_iomap(dev->parent->of_node, 0); >> - if (!priv->base) >> - return -ENOMEM; >> >> + /* keep before call to imx8mp_audiomix_reset_init_regmap() */ >> dev_set_drvdata(dev, priv); >> >> + ret = imx8mp_audiomix_reset_get_regmap(dev); >> + if (ret) >> + return dev_err_probe(dev, ret, "failed to get regmap\n"); >> + >> ret = devm_reset_controller_register(dev, &priv->rcdev); >> if (ret) >> - goto out_unmap; >> + return dev_err_probe(dev, ret, >> + "failed to register reset controller\n"); >> >> return 0; >> - >> -out_unmap: >> - iounmap(priv->base); >> - return ret; >> -} >> - >> -static void imx8mp_audiomix_reset_remove(struct auxiliary_device *adev) >> -{ >> - struct imx8mp_audiomix_reset *priv = dev_get_drvdata(&adev->dev); >> - >> - iounmap(priv->base); >> } >> >> static const struct auxiliary_device_id imx8mp_audiomix_reset_ids[] = { >> @@ -147,7 +175,6 @@ MODULE_DEVICE_TABLE(auxiliary, imx8mp_audiomix_reset_ids); >> >> static struct auxiliary_driver imx8mp_audiomix_reset_driver = { >> .probe = imx8mp_audiomix_reset_probe, >> - .remove = imx8mp_audiomix_reset_remove, > cleanup imx8mp_audiomix_reset_remove need seperate patch. as things stand now, this bit belongs in the same patch as the switch to the regmap API because of the introduction of imx8mp_audiomix_reset_get_regmap(), which uses devres. This makes the remove() function incorrect and, thus, needs to be dropped. since the cleanup is quite trivial, I don't think this would justify purposely making imx8mp_audiomix_reset_get_regmap() not use devres in this patch and then transitioning to it in a subsequent patch. > > Frank > >> .id_table = imx8mp_audiomix_reset_ids, >> }; >> >> -- >> 2.43.0 >>