From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta1.migadu.com (out-38.mta1.migadu.com [95.215.58.38]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DC07912C534 for ; Thu, 24 Sep 2026 01:25:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.38 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790213138; cv=none; b=GDVBFu7ScyR3s4W6GRp37odo7cd+PHKWs0Go2suOg2vdstWy9GiaEbPOxEtJjqF/amjtFIeZI1fLtx6sNih000jo0W1HZ101hE60x7i6OPkK2lqvysV/pyN0gyPtxLjPID+Z7OUPs5TPOioc4RZNoDASIhZr+rQ0rewWJ7sGons= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790213138; c=relaxed/simple; bh=DeMHDh3uSjVrxgU96xYeFj/2pU456l46kIvtq+IJU28=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=qx86gFkjraol+9CZfu3RFFvEyeF7St4FMFA4vGDdSDTkqiWunVzpetog8H5kSc4V8+FeReWkR7DqmhlmHV+QuQkb4SA9GyQyjtDH/j8jRuylpNxU9SXD4WuFMf8E7FqsYw/Hj6xBBC1htuM2KOeltIbODFRnZyRWfqEFcl6lTF8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=dbgw8NUk; arc=none smtp.client-ip=95.215.58.38 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="dbgw8NUk" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=DeMHDh3uSjVrxgU96xYeFj/2pU456l46kIvtq+IJU28=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1790213135; v=1; x=1790817935; b=dbgw8NUkAscS+FN3V5JCakI3PZGbtafKdWoCj382lOxe6Jz18aHVm1DNUPJby86D2AV/8SRS vayumL/e7csfewXpzm81T4PM26xe0BR/tDovvoyJWX5CI++hRxzxO/Or3dKMeV7kccVZhI4Ora3 58Vnf5sCyXt9YAG1kEj4VOE4= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id f81bd399fb250b99; Thu, 24 Sep 2026 01:25:34 +0000 X-Mizu-Trace-ID: f81bd399fb250b99 X-Migadu-Flow: FLOW_OUT Message-ID: Date: Thu, 24 Sep 2026 09:25:27 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [net-next,PATCH v1] enetc: Increase eMDIO MDC rate to 1.2 MHz To: Marek Vasut Cc: "David S. Miller" , Andrew Lunn , Clark Wang , Claudiu Manoil , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Vladimir Oltean , Wei Fang , imx@lists.linux.dev, linux-kernel@vger.kernel.org, netdev@vger.kernel.org References: <20260924003132.580306-1-marex@nabladev.com> From: Qingfang Deng In-Reply-To: <20260924003132.580306-1-marex@nabladev.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Hi, On 2026/9/24 8:30, Marek Vasut wrote: > The current eMDIO MDC rate is 558 kHz on i.MX95 B0. This is very low, > but also very compatible. However, for example NXP TJA1120 PHY needs > at minimum 1 MHz MDC clock and 558 kHz does not work with that PHY. > > As a minimum change, increase the MDC clock to 1.2 MHz which should be > equally very compatible, since even old PHYs like LAN8210Ai, KSZ8794, > DP83822 support up to 2.5 MHz MDC clock frequency, and it covers the > NXP TJA1120 as well. There is no known rationale for why the 558 kHz > was picked when the eMDIO driver was added. > > Signed-off-by: Marek Vasut > --- > Cc: "David S. Miller" > Cc: Andrew Lunn > Cc: Clark Wang > Cc: Claudiu Manoil > Cc: Eric Dumazet > Cc: Jakub Kicinski > Cc: Paolo Abeni > Cc: Vladimir Oltean > Cc: Wei Fang > Cc: imx@lists.linux.dev > Cc: linux-kernel@vger.kernel.org > Cc: netdev@vger.kernel.org > --- > NOTE: Alternatively, I can either add a DT property to configure the > clock rate, or model the clock as clock hw divider and then use > assigned-clock-rates DT property to configure the desired rate? There's a documented DT property, at Documentation/devicetree/bindings/net/mdio.yaml :   clock-frequency:     description:       Desired MDIO bus clock frequency in Hz. Values greater than IEEE 802.3       defined 2.5MHz should only be used when all devices on the bus support       the given clock speed. If the property is absent, you should configure the standard 2.5MHz rate by default, instead of 1.2MHz. > --- > drivers/net/ethernet/freescale/enetc/enetc_mdio.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/freescale/enetc/enetc_mdio.c b/drivers/net/ethernet/freescale/enetc/enetc_mdio.c > index 998aaa394e9c4..30ea91cea00e5 100644 > --- a/drivers/net/ethernet/freescale/enetc/enetc_mdio.c > +++ b/drivers/net/ethernet/freescale/enetc/enetc_mdio.c > @@ -24,7 +24,7 @@ > > #define ENETC_EMDIO_CFG \ > (MDIO_CFG_HOLD(2) | \ > - MDIO_CFG_CLKDIV(258) | \ > + MDIO_CFG_CLKDIV(138) | \ > MDIO_CFG_NEG) > > #define MDIO_CTL_DEV_ADDR(x) ((x) & 0x1f)