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dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=renesas.com; Received: from TYYPR01MB15118.jpnprd01.prod.outlook.com (2603:1096:405:1a1::11) by OSOPR01MB12410.jpnprd01.prod.outlook.com (2603:1096:604:2d6::11) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.546.15; Tue, 20 Oct 2026 14:13:20 +0000 Received: from TYYPR01MB15118.jpnprd01.prod.outlook.com ([fe80::1116:d56:8164:63b4]) by TYYPR01MB15118.jpnprd01.prod.outlook.com ([fe80::1116:d56:8164:63b4%6]) with mapi id 15.21.0522.017; Tue, 20 Oct 2026 14:13:19 +0000 Message-ID: Date: Tue, 20 Oct 2026 15:13:07 +0100 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/8] i3c: renesas: Fix zero I2C SCL rate on pure I3C buses To: Geert Uytterhoeven Cc: Wolfram Sang , Tommaso Merciai , Alexandre Belloni , Frank Li , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Magnus Damm , Stephen Boyd , Brian Masney , Jerome Brunet , Linus Walleij , linux-i3c@lists.infradead.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-clk@vger.kernel.org, linux-gpio@vger.kernel.org, stable@vger.kernel.org References: <20261020-divo-ssgrlpcsrc-2966-i3c-v1-0-30a47f25e515@renesas.com> <20261020-divo-ssgrlpcsrc-2966-i3c-v1-1-30a47f25e515@renesas.com> Content-Language: en-US From: Diogo Ivo In-Reply-To: Content-Type: text/plain; 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>> >> - i2c_total_ticks = DIV_ROUND_UP(i3c->rate, bus->scl_rate.i2c); >> + /* >> + * A pure I3C bus has no I2C devices, so the I3C core leaves >> + * scl_rate.i2c at zero if not explicitly defined in DT. The >> + * open-drain SCL fields of STDBR, which are used for the DAA >> + * pending read, are derived from it though, so fall back to >> + * the 1 MHz FM+ limit instead of programming a zero-width clock. >> + */ >> + if (!bus->scl_rate.i2c) >> + i2c_total_ticks = DIV_ROUND_UP(i3c->rate, I3C_BUS_I2C_FM_PLUS_SCL_MAX_RATE); >> + else >> + i2c_total_ticks = DIV_ROUND_UP(i3c->rate, bus->scl_rate.i2c); >> + >> i3c_total_ticks = DIV_ROUND_UP(i3c->rate, bus->scl_rate.i3c); > > This looks like a good opportunity to use the shortened tertiary ?:-operator: > > bus->scl_rate.i2c ?: I3C_BUS_I2C_FM_PLUS_SCL_MAX_RATE Ack, will change in v2. Thanks for the review, Diogo >> >> i2c_parse_fw_timings(&m->dev, &t, true); > > Gr{oetje,eeting}s, > > Geert > > -- > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org > > In personal conversations with technical people, I call myself a hacker. But > when I'm talking to journalists I just say "programmer" or something like that. > -- Linus Torvalds