Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755859Ab3C0Jz1 (ORCPT ); Wed, 27 Mar 2013 05:55:27 -0400 Received: from mail-ob0-f172.google.com ([209.85.214.172]:35425 "EHLO mail-ob0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755833Ab3C0JzZ (ORCPT ); Wed, 27 Mar 2013 05:55:25 -0400 MIME-Version: 1.0 In-Reply-To: References: <1364368183-24420-1-git-send-email-mturquette@linaro.org> Date: Wed, 27 Mar 2013 15:25:24 +0530 Message-ID: Subject: Re: [PATCH v4] clk: allow reentrant calls into the clk framework From: Viresh Kumar To: Thomas Gleixner Cc: Mike Turquette , linaro-kernel@lists.linaro.org, patches@linaro.org, linux-kernel@vger.kernel.org, Laurent Pinchart , David Brown , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1256 Lines: 34 On 27 March 2013 15:10, Thomas Gleixner wrote: > On Wed, 27 Mar 2013, Mike Turquette wrote: > >> Reentrancy into the clock framework from the clk.h api is necessary >> for clocks that are prepared and unprepared via i2c_transfer (which >> includes many PMICs and discrete audio chips) as well as for several >> other use cases. > > That explanation sucks. > > Why does an i2c clock need reentrancy? Just because it's i2c or what? I am noway connected to this development but was just going through your mail and i think i might know the answer why is this required. Consider an example where an external chip has clock controller and has bits which can be programmed to enable/disable clock. And this chip is connected via spi/i2c to SoC. clk_prepare(peripheral on external chip) -> i2c_xfer(to write to external chips register) -> clk_enable(i2c controller) ->controller-xfer-routine.. and finally we enable clk here... Sorry if i am on the wrong side :) -- viresh -- 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/