From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754108Ab3LQN0n (ORCPT ); Tue, 17 Dec 2013 08:26:43 -0500 Received: from mailout4.w1.samsung.com ([210.118.77.14]:25250 "EHLO mailout4.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752162Ab3LQN0k (ORCPT ); Tue, 17 Dec 2013 08:26:40 -0500 X-AuditID: cbfec7f5-b7f6f6d000005b3b-c4-52b0510f6edb From: Kamil Debski To: "'Anton Tikhomirov'" , 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, kishon@ti.com, Tomasz Figa , Sylwester Nawrocki , Marek Szyprowski , 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 References: <1386246579-25141-1-git-send-email-k.debski@samsung.com> <1386246579-25141-4-git-send-email-k.debski@samsung.com> <006a01cef551$7fb4e240$7f1ea6c0$%tikhomirov@samsung.com> In-reply-to: <006a01cef551$7fb4e240$7f1ea6c0$%tikhomirov@samsung.com> Subject: RE: [PATCH v4 3/9] phy: Add new Exynos USB PHY driver Date: Tue, 17 Dec 2013 14:26:37 +0100 Message-id: <02d201cefb2b$9e04e710$da0eb530$%debski@samsung.com> MIME-version: 1.0 Content-type: text/plain; charset=us-ascii Content-transfer-encoding: 7bit X-Mailer: Microsoft Office Outlook 12.0 Thread-index: Ac7xtb/TcbT2JoEKQI6IBVag+SxyjgDmHfwwAXcg4IA= Content-language: pl X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFprFIsWRmVeSWpSXmKPExsVy+t/xy7r8gRuCDOb+57ZYsvsGq8X8I+dY LfrfLGS1aLtykN3i8sJLrBYXnvawWZxtegPk7prDZjHj/D4mi0XLWpkt1h65y25xtv82m8XE pmnsFue3dDJZHH7TzmqxfsZrFouOswfZHQQ9Lvf1MnnsnHWX3ePOtT1sHn1bVjF6HL+xncnj 8ya5ALYoLpuU1JzMstQifbsEroyL63rYCh6zVbRPn8HawLietYuRk0NCwETifU8/lC0mceHe erYuRi4OIYGljBIn9lxkh3AamCT+/1zC2MXIwcEmoCmx6p4HSFxEYB2jxNYns1hAHGaBy0wS R+6/ZYXo2MUosaV5EzvIXE4BV4nHO1cwg9jCAnYS57d3MYLYLAKqEoc6toLFeQUcJN5c/MwE YQtK/Jh8jwXEZhbQkli/8zgThC0vsXnNW2aQKyQE1CUe/dUFCYsIWEn8m9kDVS4icbfhOesE RqFZSCbNQjJpFpJJs5C0LGBkWcUomlqaXFCclJ5rpFecmFtcmpeul5yfu4kREp9fdzAuPWZ1 iFGAg1GJh/fAsvVBQqyJZcWVuYcYJTiYlUR4v3lsCBLiTUmsrEotyo8vKs1JLT7EyMTBKdXA mPbxVlVdwd/3ly9t7zx+XD9n6d/Y0qQ9f5nu5XaGyWwXvTzV5saXtM4zD+5ESafznq7hXskg w/Nw1ZTde1alv2q5+f1AelHqbXHXqzz9xV8mLGTJPfn55LEjAgUrdAJYD/3zX3UuUWSuZau2 tYznPRv2EE3uhwLWjyLCvzqkXXigtvW1f+kOYSWW4oxEQy3mouJEACO/jf6tAgAA Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Anton, > From: Anton Tikhomirov [mailto:av.tikhomirov@samsung.com] > Sent: Tuesday, December 10, 2013 3:43 AM > > Hi Kamil, > > Same USB2.0 PHY may be used by several HCDs, for example EHCI and OHCI. > Consider the situation, when EHCI stops using the PHY and calls > power_off, then OHCI becomes non-operational. In other words, PHY > power_on and power_off calls must be balanced. > > Shall we handle it in your driver? (usage count?) Please look in the drivers/phy/phy-core.c file. Usage count is handled there - see phy_power_on and phy_power_off functions. I understand that after both EHCI and OHCI power on the phy, the usage count is 2. So powering off one of them (EHCI for instance) the usage count is still 1, so the OHCI should still work properly. [snip] Best wishes, -- Kamil Debski Samsung R&D Institute Poland