From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.gentoo.org (woodpecker.gentoo.org [140.211.166.183]) (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 5B5242116F1 for ; Wed, 9 Apr 2025 21:43:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=140.211.166.183 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744235031; cv=none; b=FuKumdmKJa+OB6xFJfEfuEINsx0+KttFn2hq7W5g+bUaDrCxFfL97bTTN3FATh6tccxLtwlPE7KsUyOrsZwcobwxRqIQ8IOKIo7XjAX95ul0iD9uSj9tI23cHi2ggB7zs165wp67b/S1AkVLnROffrhkrjnMKEJm0KUCiKACJ1c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744235031; c=relaxed/simple; bh=eesypCNmz5sJKsF5KpZG/L0WnupeOJYtqoN4SCn0pyw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=qX5svtsPE2wJo/WS/pRektXRWWKxdE9qz7pygi6lVHm1DsPdJWp9wi1DpdqyBaMWSwvfa19acszxlh/sxsPEHXnp1T462Kwwcm0pETwPmDH5avQu1x7mSsuEkWv2wnhUJTZibraZq5grOegME5tKcWT/pMATnvwQtbM2+/kudOw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gentoo.org; spf=pass smtp.mailfrom=gentoo.org; arc=none smtp.client-ip=140.211.166.183 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gentoo.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gentoo.org Received: from localhost (unknown [116.232.27.72]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (prime256v1) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: dlan) by smtp.gentoo.org (Postfix) with ESMTPSA id 426CB343183; Wed, 09 Apr 2025 21:43:48 +0000 (UTC) Date: Wed, 9 Apr 2025 21:43:45 +0000 From: Yixun Lan To: Alex Elder Cc: gregkh@linuxfoundation.org, jirislaby@kernel.org, robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, benjamin.larsson@genexis.eu, bastien.curutchet@bootlin.com, andriy.shevchenko@linux.intel.com, u.kleine-koenig@baylibre.com, lkundrak@v3.sk, devicetree@vger.kernel.org, linux-serial@vger.kernel.org, spacemit@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 2/2] serial: 8250_of: add support for an optional bus clock Message-ID: <20250409214345-GYA19066@gentoo> References: <20250409192213.1130181-1-elder@riscstar.com> <20250409192213.1130181-3-elder@riscstar.com> Precedence: bulk X-Mailing-List: spacemit@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250409192213.1130181-3-elder@riscstar.com> Hi Alex, On 14:22 Wed 09 Apr , Alex Elder wrote: > The SpacemiT UART requires a bus clock to be enabled, in addition to > it's "normal" core clock. Look up the optional bus clock by name, > and if that's found, look up the core clock using the name "core". > > Supplying a bus clock is optional. If no bus clock is needed, the > the first/only clock is used for the core clock. > > Signed-off-by: Alex Elder > --- > v2: Update logic to more check for the optional bus clock first > > drivers/tty/serial/8250/8250_of.c | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-) > > diff --git a/drivers/tty/serial/8250/8250_of.c b/drivers/tty/serial/8250/8250_of.c > index 11c860ea80f60..a90a5462aa72a 100644 > --- a/drivers/tty/serial/8250/8250_of.c > +++ b/drivers/tty/serial/8250/8250_of.c > @@ -123,7 +123,16 @@ static int of_platform_serial_setup(struct platform_device *ofdev, > > /* Get clk rate through clk driver if present */ > if (!port->uartclk) { > - info->clk = devm_clk_get_enabled(dev, NULL); > + struct clk *bus_clk; we also need to handle clk in suspend/resume procedure, so I think you need to put bus_clk inside struct of_serial_info.. > + > + bus_clk = devm_clk_get_optional_enabled(dev, "bus"); for the 'optional', we can interpret it's optional for other vendor UART, but a must required clk for SpacemiT's k1 UART controller would it better to guard this inside a compatible test or even introduce a flag in compatible data? if (of_device_is_compatible(pdev->dev.of_node, "spacemit,k1-uart")) { bus_clk = devm_clk_get_enabled(dev, "bus"); .. } } > + if (IS_ERR(bus_clk)) { > + ret = dev_err_probe(dev, PTR_ERR(bus_clk), "failed to get bus clock\n"); > + goto err_pmruntime; > + } > + > + /* If the bus clock is required, core clock must be named */ > + info->clk = devm_clk_get_enabled(dev, bus_clk ? "core" : NULL); > if (IS_ERR(info->clk)) { > ret = dev_err_probe(dev, PTR_ERR(info->clk), "failed to get clock\n"); > goto err_pmruntime; > -- > 2.45.2 > -- Yixun Lan (dlan) Gentoo Linux Developer GPG Key ID AABEFD55