From nobody Sun Dec 28 04:39:26 2025 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A7B0DC4332F for ; Tue, 12 Dec 2023 21:46:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1377459AbjLLVp4 (ORCPT ); Tue, 12 Dec 2023 16:45:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57730 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1377344AbjLLVph (ORCPT ); Tue, 12 Dec 2023 16:45:37 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B539EAB for ; Tue, 12 Dec 2023 13:45:43 -0800 (PST) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CFDE0C433C7; Tue, 12 Dec 2023 21:45:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1702417543; bh=61xu+OcPj5V/1U8yttDpwKsOSr89T9ROKbwgf4LauZA=; h=From:To:Cc:Subject:Date:From; b=T3TKEoD2DFoTDRZykH5hmLSR6hlqT0AnBgKiI3oIuSwoqnWxisE4jV/vsLrsRXeEK 0WZtTjZAjZYgIYHeFiTT6MIU2qeh0t8gVZ0/oco5JFhrqOFVIjTSoeQNoQVqzFKqbk elZeBAu284TS6ifRfnpUQjTqccQO9uuxZM4P0IJ+QVYDnm2MYgYYU/QZ3etN4oPOVY NLgzc8OcdUVl3a+jVOD2dXqNTDKTZLDSfwS3V7zvb8dnY6bAboBZ8Tu3wcUnHnRYz+ 1vo7iRWVaKZ6M/VqexWF3wTR8ah4R0yZZ0lg45/S2pFBrVNkSpLF2TQDTqEElGPxPM rTZwO2qzO3u/w== From: Arnd Bergmann To: Pavel Machek , Lee Jones , Chen-Yu Tsai , Jernej Skrabec , Samuel Holland , Nathan Chancellor , Guo Ren , Palmer Dabbelt Cc: Arnd Bergmann , Nick Desaulniers , Bill Wendling , Justin Stitt , linux-leds@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-sunxi@lists.linux.dev, linux-kernel@vger.kernel.org, llvm@lists.linux.dev Subject: [PATCH] leds: sun50i-a100: avoid division-by-zero warning Date: Tue, 12 Dec 2023 22:45:22 +0100 Message-Id: <20231212214536.175327-1-arnd@kernel.org> X-Mailer: git-send-email 2.39.2 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Arnd Bergmann When CONFIG_COMMON_CLK is disabled, e.g. on an x86 randconfig compile test, clang reports a field overflow from propagating the result of a division by zero: drivers/leds/leds-sun50i-a100.c:309:12: error: call to '__compiletime_asser= t_265' declared with 'error' attribute: FIELD_PREP: value too large for the= field control =3D FIELD_PREP(LEDC_T01_TIMING_CTRL_REG_T1H, timing->t1h_ns= / cycle_ns) | Avoid the problem by adding an explicit check for the zero value here. Alte= rnatively the assertion could be avoided with a Kconfig dependency on COMMON_CLK. Fixes: 090a25ad9798 ("leds: sun50i-a100: New driver for the A100 LED contro= ller") Signed-off-by: Arnd Bergmann Reviewed-by: Guo Ren --- drivers/leds/leds-sun50i-a100.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/leds/leds-sun50i-a100.c b/drivers/leds/leds-sun50i-a10= 0.c index e4a7e692a908..171cefd1ea0d 100644 --- a/drivers/leds/leds-sun50i-a100.c +++ b/drivers/leds/leds-sun50i-a100.c @@ -303,9 +303,13 @@ static void sun50i_a100_ledc_set_timing(struct sun50i_= a100_ledc *priv) { const struct sun50i_a100_ledc_timing *timing =3D &priv->timing; unsigned long mod_freq =3D clk_get_rate(priv->mod_clk); - u32 cycle_ns =3D NSEC_PER_SEC / mod_freq; + u32 cycle_ns; u32 control; =20 + if (!mod_freq) + return; + + cycle_ns =3D NSEC_PER_SEC / mod_freq; control =3D FIELD_PREP(LEDC_T01_TIMING_CTRL_REG_T1H, timing->t1h_ns / cyc= le_ns) | FIELD_PREP(LEDC_T01_TIMING_CTRL_REG_T1L, timing->t1l_ns / cycle_ns) | FIELD_PREP(LEDC_T01_TIMING_CTRL_REG_T0H, timing->t0h_ns / cycle_ns) | --=20 2.39.2