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 86D7FD11183 for ; Thu, 27 Nov 2025 13:22:57 +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:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=P6FXAJgkkzG4zg/OhYkDtMBzoiFKim//OBB3h/UAam8=; b=C/j5ihQSo7IjlZfK3OD6k33MRs /ZdRalkucnkUdH2hBSD6ivLCWTox/GNaoT7hHmD8iT0bCWfEBZe5slYVrhRW12nzK4XGz4tU80XEr yXW3l8GajmDM/YAmZxxfO+K5PjRo5hQnKgof4PEeq7Pvf7vHL2mTSQwBHtae/GwVzGmAmMumkZ3vS EitadwtqMzZ42tmHiCNWmIhF6FBCkwxRxt9YyjCACcbDZx6WiMcJdWNXkmyHUvH0ySggy0qQA3l2i ruxNGwfx6yUJAIshgbYdxYN23acu1Gc2a+xlKrsbnPh0RsmeUN26IKq4/W4TOPPcmiRCYrBLJRHle B/rtd5og==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vObxV-0000000Gf6O-1p3K; Thu, 27 Nov 2025 13:22:53 +0000 Received: from akranes.kaiser.cx ([2a0a:4cc0:1:11ef:4484:ccff:febf:ddfa]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vObxS-0000000Gf5v-3wsP for linux-arm-kernel@lists.infradead.org; Thu, 27 Nov 2025 13:22:52 +0000 Received: from martin by akranes.kaiser.cx with local (Exim 4.96) (envelope-from ) id 1vObxC-0007Pt-0N; Thu, 27 Nov 2025 14:22:34 +0100 Date: Thu, 27 Nov 2025 14:22:34 +0100 From: Martin Kaiser To: Geert Uytterhoeven Cc: Jean-Michel Hautbois via B4 Relay , Greg Ungerer , Olivia Mackall , Herbert Xu , Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , linux-m68k@lists.linux-m68k.org, linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org, imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org, Jean-Michel Hautbois , Frank Li Subject: Re: [PATCH v4 1/2] hwrng: imx-rngc: Use optional clock Message-ID: References: <20251126-b4-m5441x-add-rng-support-v4-0-5309548c9555@yoseli.org> <20251126-b4-m5441x-add-rng-support-v4-1-5309548c9555@yoseli.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251127_052251_009720_489D44FB X-CRM114-Status: GOOD ( 23.05 ) 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 Hi Geert, Thus wrote Geert Uytterhoeven (geert@linux-m68k.org): > Hi Martin, > On Wed, 26 Nov 2025 at 21:30, Martin Kaiser wrote: > > Thus wrote Jean-Michel Hautbois via B4 Relay (devnull+jeanmichel.hautbois.yoseli.org@kernel.org): > > > From: Jean-Michel Hautbois > > > Change devm_clk_get() to devm_clk_get_optional() to support platforms > > > where the RNG clock is always enabled and not exposed via the clock > > > framework (such as ColdFire MCF54418). > > > Reviewed-by: Frank Li > > > Signed-off-by: Jean-Michel Hautbois > > > --- > > > drivers/char/hw_random/imx-rngc.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > diff --git a/drivers/char/hw_random/imx-rngc.c b/drivers/char/hw_random/imx-rngc.c > > > index 241664a9b5d9..d6a847e48339 100644 > > > --- a/drivers/char/hw_random/imx-rngc.c > > > +++ b/drivers/char/hw_random/imx-rngc.c > > > @@ -259,7 +259,7 @@ static int __init imx_rngc_probe(struct platform_device *pdev) > > > if (IS_ERR(rngc->base)) > > > return PTR_ERR(rngc->base); > > > - rngc->clk = devm_clk_get(&pdev->dev, NULL); > > > + rngc->clk = devm_clk_get_optional(&pdev->dev, NULL); > > > if (IS_ERR(rngc->clk)) > > > return dev_err_probe(&pdev->dev, PTR_ERR(rngc->clk), "Cannot get rng_clk\n"); > > The clock is not optional on a standard imx25 system. If it's missing in the > > device tree, the rngb will not work and we should not load the driver. > As the clocks property is marked required in > Documentation/devicetree/bindings/rng/imx-rng.yaml, "make dtbs_check" > should flag a missing clock. > > Should we call devm_clk_get or devm_clk_get_optional, depending on the > > detected device? > That can quickly lead to complex code. Nowadays it is fine to rely on > "make dtbs_check" for some part of the validation. ok, understood. With this clarification, I'm happy with the patch. Reviewed-by: Martin Kaiser Thanks, Martin