From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751992AbaCFJCc (ORCPT ); Thu, 6 Mar 2014 04:02:32 -0500 Received: from mailout2.samsung.com ([203.254.224.25]:13196 "EHLO mailout2.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750828AbaCFJC0 (ORCPT ); Thu, 6 Mar 2014 04:02:26 -0500 X-AuditID: cbfee691-b7efc6d0000039d3-2e-5318399f84dc From: Anton Tikhomirov To: "'Kishon Vijay Abraham I'" , "'Kamil Debski'" , linux-kernel@vger.kernel.org, linux-samsung-soc@vger.kernel.org, linux-usb@vger.kernel.org, devicetree@vger.kernel.org Cc: kyungmin.park@samsung.com, t.figa@samsung.com, s.nawrocki@samsung.com, m.szyprowski@samsung.com, gautam.vivek@samsung.com, mat.krawczuk@gmail.com, yulgon.kim@samsung.com, p.paneri@samsung.com, jg1.han@samsung.com, galak@codeaurora.org, matt.porter@linaro.org, tjakobi@math.uni-bielefeld.de, stern@rowland.harvard.edu, sander@humilis.net References: <1394033288-5551-1-git-send-email-k.debski@samsung.com> <1394033288-5551-4-git-send-email-k.debski@samsung.com> <005c01cf3915$c53476c0$4f9d6440$%tikhomirov@samsung.com> <53183220.3040606@ti.com> <006201cf3919$5f760750$1e6215f0$%tikhomirov@samsung.com> <5318384B.7020009@ti.com> In-reply-to: <5318384B.7020009@ti.com> Subject: RE: [PATCH v9 3/4] phy: Add new Exynos USB 2.0 PHY driver Date: Thu, 06 Mar 2014 18:02:22 +0900 Message-id: <006301cf391a$c99c7280$5cd55780$%tikhomirov@samsung.com> MIME-version: 1.0 Content-type: text/plain; charset=Windows-1252 Content-transfer-encoding: 7bit X-Mailer: Microsoft Office Outlook 12.0 Thread-index: Ac85GgmZfoxLgW4rTLqFe8gqPp77bwAACVdg Content-language: en-us X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFtrBKsWRmVeSWpSXmKPExsVy+t8zY935lhLBBk0XVCzmHznHatH/ZiGr RduVg+wWlxdeYrX48foCm8WFpz1sFmeb3gDFds1hs5hxfh+TxaJlrcwWa4/cZbc423+bzWJi 0zR2i/NbOpksDr9pZ7VYcW83u8WE30C962e8ZrFoW/2B1aLj7EF2BxGPy329TB47Z91l9/j0 djGzx51re9g8/h1j95h99wejR9+WVYwex29sZ/L4vEkugDOKyyYlNSezLLVI3y6BK2PhrUVs BU8kK2ZP+87cwLhPpIuRk0NCwERiw8I1jBC2mMSFe+vZuhi5OIQEljFKLNr5nR2maM2NPWBF QgLTGSVOftCGKPrHKPHx9ApWkASbgJHEy4MbmUESIgIXGSWmTt/LCOIwC9xhkvgyfx8TRMtq Jom3y6YzgbRwCqhJHNxwlgXEFhZwkrjwvBEsziKgKnFz2iWwfbwCLhKveldD2YISPybfA6tn FtCT+PjnNiOELS+xec1boNUcQLeqSzz6qwsSFgG66PjeOcwQJeISkx48ZAe5QULgDYfEzD6I +SwCAhLfJh9igeiVldh0gBniZUmJgytusExglJiFZPMsJJtnIdk8C8mKBYwsqxhFUwuSC4qT 0otM9YoTc4tL89L1kvNzNzFCUs3EHYz3D1gfYkwGWj+RWUo0OR+YqvJK4g2NzYwsTE1MjY3M Lc1IE1YS501/lBQkJJCeWJKanZpakFoUX1Sak1p8iJGJg1OqgTF4XtmBbw7BaR1nb66X8bP9 pZMSy2xTMy3f7OTCBpOav8vPv9wZEMkjHMnudf5xa8S2Nbs2OPF1HmUzkf6id9f1VgG/cnm4 2oRpHvcFIg13u62d/1VgjebVkggPiaRb13QZ6tgfrtwRGZd+cY2tSsA1tg2yV7lenW9V70vc 66Nvc0fo3aYn9UosxRmJhlrMRcWJADAl1tNLAwAA X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFprKJsWRmVeSWpSXmKPExsVy+t9jQd35lhLBBksPyVnMP3KO1aL/zUJW i7YrB9ktLi+8xGrx4/UFNosLT3vYLM42vQGK7ZrDZjHj/D4mi0XLWpkt1h65y25xtv82m8XE pmnsFue3dDJZHH7Tzmqx4t5udosJv4F61894zWLRtvoDq0XH2YPsDiIel/t6mTx2zrrL7vHp 7WJmjzvX9rB5/DvG7jH77g9Gj74tqxg9jt/YzuTxeZNcAGdUA6NNRmpiSmqRQmpecn5KZl66 rZJ3cLxzvKmZgaGuoaWFuZJCXmJuqq2Si0+ArltmDtBvSgpliTmlQKGAxOJiJX07TBNCQ9x0 LWAaI3R9Q4LgeowM0EDCOsaMhbcWsRU8kayYPe07cwPjPpEuRk4OCQETiTU39jBC2GISF+6t ZwOxhQSmM0qc/KDdxcgFZP9jlPh4egUrSIJNwEji5cGNzCAJEYGLjBJTp+9lBHGYBe4wSXyZ v48JomU1k8TbZdOZQFo4BdQkDm44ywJiCws4SVx43ggWZxFQlbg57RLYbl4BF4lXvauhbEGJ H5PvgdUzC+hJfPxzmxHClpfYvOYt0GoOoFvVJR791QUJiwBddHzvHGaIEnGJSQ8esk9gFJqF ZNIsJJNmIZk0C0nLAkaWVYyiqQXJBcVJ6blGesWJucWleel6yfm5mxjBieyZ9A7GVQ0WhxgF OBiVeHg3+IkHC7EmlhVX5h5ilOBgVhLh3WIoESzEm5JYWZValB9fVJqTWnyIMRno0YnMUqLJ +cAkm1cSb2hsYmZkaWRmYWRibk6asJI478FW60AhgfTEktTs1NSC1CKYLUwcnFINjC1dKt0q 3RPi6wVLglVOv9yXuv5I/4X8iL6MTStWnJ//hvVj7cbzU19OjM6qujhzikXzJfkylYuT/OWC Nf+90twQ9Psyz5N9jeru1vMMy75+ydnMFm/jH/hzSsOBRaw6hZ0bjY1ft70uuPtzz5XNR4yb j9R9e6i08vJyM9kTOofOCXwrt7Uyy1BiKc5INNRiLipOBACguJMCqAMAAA== DLP-Filter: Pass X-MTR: 20000000000000000@CPGS X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, > Subject: Re: [PATCH v9 3/4] phy: Add new Exynos USB 2.0 PHY driver > > Hi, > > On Thursday 06 March 2014 02:22 PM, Anton Tikhomirov wrote: > > Hello, > > > >> Subject: Re: [PATCH v9 3/4] phy: Add new Exynos USB 2.0 PHY driver > >> > >> > >> > >> On Thursday 06 March 2014 01:56 PM, Anton Tikhomirov wrote: > >>> Hi Kamil, > >>> > >>> ... > >>> > >>>> +| 3. Supporting SoCs > >>>> ++-------------------- > >>>> + > >>>> +To support a new SoC a new file should be added to the > drivers/phy > >>>> +directory. Each SoC's configuration is stored in an instance of > the > >>>> +struct samsung_usb2_phy_config. > >>>> + > >>>> +struct samsung_usb2_phy_config { > >>>> + const struct samsung_usb2_common_phy *phys; > >>>> + unsigned int num_phys; > >>>> + bool has_mode_switch; > >>> > >>> You missed rate_to_clk here. > >>> > >>>> +}; > >>>> + > >>> > >>> ... > >>> > >>>> diff --git a/drivers/phy/phy-samsung-usb2.c b/drivers/phy/phy- > >> samsung- > >>>> usb2.c > >>>> new file mode 100644 > >>>> index 0000000..c3b7719 > >>>> --- /dev/null > >>>> +++ b/drivers/phy/phy-samsung-usb2.c > >>>> @@ -0,0 +1,222 @@ > >>>> +/* > >>>> + * Samsung SoC USB 1.1/2.0 PHY driver > >>>> + * > >>>> + * Copyright (C) 2013 Samsung Electronics Co., Ltd. > >>>> + * Author: Kamil Debski > >>>> + * > >>>> + * This program is free software; you can redistribute it and/or > >>>> modify > >>>> + * it under the terms of the GNU General Public License version 2 > >> as > >>>> + * published by the Free Software Foundation. > >>>> + */ > >>>> + > >>>> +#include > >>>> +#include > >>>> +#include > >>>> +#include > >>>> +#include > >>>> +#include > >>>> +#include > >>>> +#include > >>>> +#include "phy-samsung-usb2.h" > >>>> + > >>>> +static int samsung_usb2_phy_power_on(struct phy *phy) > >>>> +{ > >>>> + struct samsung_usb2_phy_instance *inst = > phy_get_drvdata(phy); > >>>> + struct samsung_usb2_phy_driver *drv = inst->drv; > >>>> + int ret; > >>>> + > >>>> + dev_dbg(drv->dev, "Request to power_on \"%s\" usb phy\n", > >>>> + inst->cfg->label); > >>>> + ret = clk_prepare_enable(drv->clk); > >>> > >>> clk_prepare_enable() can sleep, and therefore doesn't allow > >>> samusng_usb2_phy_power_on() to be used in atomic context > >>> (e.g. inside spin_lock-ed area), what sometimes may be desirable. > >>> What about to prepare clock in probe, and just enable it here > >>> (note: clk_enable() doesn't sleep). > >> > >> The PHY power-on callback is anyway called with mutex held, so I > guess > >> it's fine to have clk_prepare_enable() here. > > > > If we rely totally on generic PHY functions such as phy_power_on() > > and friends, why do we need to use locking in callbacks at all. > > Didn't get you.. We don't want to invoke power_on when init is getting > executed or you don't want power on or power off to get executed > simultaneously right? So we need to protect it. I mean callbacks such as samsung_usb2_phy_power_on() which uses spin_lock. It's already protected by mutex in phy_power_on(). > > Cheers > Kishon