From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <benh@kernel.crashing.org>
Authentication-Results: lists.ozlabs.org; spf=permerror (mailfrom)
 smtp.mailfrom=kernel.crashing.org (client-ip=63.228.1.57;
 helo=gate.crashing.org; envelope-from=benh@kernel.crashing.org;
 receiver=<UNKNOWN>)
Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none)
 header.from=kernel.crashing.org
Received: from gate.crashing.org (gate.crashing.org [63.228.1.57])
 (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits))
 (No client certificate requested)
 by lists.ozlabs.org (Postfix) with ESMTPS id 41VFl73kT5zF3Hf
 for <openbmc@lists.ozlabs.org>; Tue, 17 Jul 2018 19:45:39 +1000 (AEST)
Received: from localhost (localhost.localdomain [127.0.0.1])
 by gate.crashing.org (8.14.1/8.14.1) with ESMTP id w6H9jDEC003617;
 Tue, 17 Jul 2018 04:45:14 -0500
Message-ID: <dea1363bae3cfaa7c8244b64bfab7dfddaae8e4a.camel@kernel.crashing.org>
Subject: Re: [PATCH linux dev-4.17 1/7] clk: Aspeed: Modify clk-aspeed.c
 driver probe sequence
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Ryan Chen <ryanchen.aspeed@gmail.com>
Cc: openbmc@lists.ozlabs.org, joel@jms.id.au, andrew@aj.id.au,
 ryan_chen@aspeedtech.com, mine260309@gmail.com
Date: Tue, 17 Jul 2018 19:45:13 +1000
In-Reply-To: <20180717060411.GA10750@ryan-ubuntu>
References: <1531286230-28453-1-git-send-email-ryanchen.aspeed@gmail.com>
 <1531286230-28453-2-git-send-email-ryanchen.aspeed@gmail.com>
 <84064771141b017e5fe3cafef8dc8307f5d97eba.camel@kernel.crashing.org>
 <20180717060411.GA10750@ryan-ubuntu>
Content-Type: text/plain; charset="UTF-8"
X-Mailer: Evolution 3.28.3 (3.28.3-1.fc28) 
Mime-Version: 1.0
Content-Transfer-Encoding: 7bit
X-BeenThere: openbmc@lists.ozlabs.org
X-Mailman-Version: 2.1.27
Precedence: list
List-Id: Development list for OpenBMC <openbmc.lists.ozlabs.org>
List-Unsubscribe: <https://lists.ozlabs.org/options/openbmc>,
 <mailto:openbmc-request@lists.ozlabs.org?subject=unsubscribe>
List-Archive: <http://lists.ozlabs.org/pipermail/openbmc/>
List-Post: <mailto:openbmc@lists.ozlabs.org>
List-Help: <mailto:openbmc-request@lists.ozlabs.org?subject=help>
List-Subscribe: <https://lists.ozlabs.org/listinfo/openbmc>,
 <mailto:openbmc-request@lists.ozlabs.org?subject=subscribe>
X-List-Received-Date: Tue, 17 Jul 2018 09:45:40 -0000

On Tue, 2018-07-17 at 14:04 +0800, Ryan Chen wrote:
> On Wed, Jul 11, 2018 at 03:47:56PM +1000, Benjamin Herrenschmidt wrote:
> > On Wed, 2018-07-11 at 13:17 +0800, Ryan Chen wrote:
> > > In Aspeed's SoC, all IP clk gating and pll parameter is in scu
> > > controller, before IP driver probe, scu driver need prepare for it.
> > > So buildin_platform_driver to core_initcall.
> > > 
> > > Signed-off-by: Ryan Chen <ryanchen.aspeed@gmail.com>
> > > ---
> > >  drivers/clk/clk-aspeed.c | 7 ++++++-
> > >  1 file changed, 6 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/clk/clk-aspeed.c b/drivers/clk/clk-aspeed.c
> > > index 8796b8a..9e55743 100644
> > > --- a/drivers/clk/clk-aspeed.c
> > > +++ b/drivers/clk/clk-aspeed.c
> > > @@ -573,7 +573,12 @@ static struct platform_driver aspeed_clk_driver = {
> > >  		.suppress_bind_attrs = true,
> > >  	},
> > >  };
> > > -builtin_platform_driver(aspeed_clk_driver);
> > > +
> > > +static int __init aspeed_clk_init(void)
> > > +{
> > > +	return platform_driver_register(&aspeed_clk_driver);
> > > +}
> > > +core_initcall(aspeed_clk_init);
> > >  
> > >  static void __init aspeed_ast2400_cc(struct regmap *map)
> > >  {
> > 
> > It's generally considered dangerous to register drivers at core
> > initcall time.
> 
> Understand. 
> 
> But if interrupt controller have clk gating. 
> the scu driver should be eraly than irq chip driver probe. 
> Is this point is reasonable? 

I'm not sure I understand what you are trying to solve other than
making sure the clock driver is loaded before everything else. Joel, do
we have a way to ensure that ? I noticed all other clock drivers use
that macro to be initialized at of_clk_init, any reason we don't ?
> 
> > 
> > Any reason we don't use the generic clock driver registration mechanism
> > that runs at of_clk_init() time ?
> 
> I will use "if (gate->reset_idx == aspeed_resets[ASPEED_RESET_SDHCI])", 
> is it suitable ?  

I'm on holiday, I don't have the code at hand to check. Joel ? What do
you reckon ?

> 
> Ryan Chen
> 
> > 
> > Cheers,
> > Ben.
> >