Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964902AbbGHQyz (ORCPT ); Wed, 8 Jul 2015 12:54:55 -0400 Received: from mail-pa0-f44.google.com ([209.85.220.44]:36415 "EHLO mail-pa0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933005AbbGHQyt convert rfc822-to-8bit (ORCPT ); Wed, 8 Jul 2015 12:54:49 -0400 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT To: Leo Yan , "Jassi Brar" From: Michael Turquette In-Reply-To: <20150707140424.GA12992@leoy-linaro> Cc: "Russell King , Linux Kernel Mailing List" , linux-clk@vger.kernel.org, sboyd@codeaurora.org References: <20150706113355.GA6967@leoy-linaro> <20150707140424.GA12992@leoy-linaro> Message-ID: <20150708165429.9112.88891@quantum> User-Agent: alot/0.3.5 Subject: Re: Query: Clock driver requests mailbox channel Date: Wed, 08 Jul 2015 09:54:29 -0700 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2745 Lines: 66 Cc'ing linux-clk and Stephen Boyd Quoting Leo Yan (2015-07-07 07:04:25) > On Tue, Jul 07, 2015 at 10:54:55AM +0530, Jassi Brar wrote: > > On Mon, Jul 6, 2015 at 5:03 PM, Leo Yan wrote: > > > Hi all, > > > > > > i'm working with one clock driver, which will invoke mailbox API to > > > request the mailbox channel and send message. > > > > > > Usually clock driver will init with devicetree, below is the example: > > > CLK_OF_DECLARE(hi6220_clk_power, "hisilicon,hi6220-clock-power", > > > hi6220_clk_power_init); > > > > > > Clock init function it will pass the pointer of struct device_node > > > but not the pointer of struct device. So finally it's difficult to > > > invoke mailbox API *mbox_request_channel()*, due it need use the > > > struct device to search DT's property "mboxes". > > > > > > I want to find which is the best way to resolve this issue, so do you > > > suggest clock driver to manually register one device? Or can we add > > > one more API to request the mailbox channel directly with device_node? > > > > > IIUC, such clocks (that require platform resources) should be > > populated from the platform_device's probe()? > > Thanks for response, Jassi. If we use general platform_device's probe() > function, then we can smoothly to get device poiner. > > But if we use the method with CLK_OF_DECLARE, then i tried to get device > pointer with the function of_find_device_by_node(), it will return the > device pointer is NULL. But this is the common case in many clock drivers. Using platform_device is the right approach. Stephen has been trying to encourage use of that and discourage use of CLK_OF_DECLARE where possible. If your clock driver needs to register some early clocks then perhaps those can be handled separately with CLK_OF_DECLARE and the rest can be managed through a proper platform_driver? > > So i just wander if can provide another mailbox API for this case, > which will only need to pass device node pointer? I can't comment on the mailbox API question, but I think the Right Thing is to use a platform_driver for your clock driver, which would solve your particular issue. This is something we are encouraging in Clock Land ;) Regards, Mike > > Thanks, > Leo Yan > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/