From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030559AbdAEH0a convert rfc822-to-8bit (ORCPT ); Thu, 5 Jan 2017 02:26:30 -0500 Received: from mail-out.m-online.net ([212.18.0.10]:49289 "EHLO mail-out.m-online.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S967039AbdAEH0Q (ORCPT ); Thu, 5 Jan 2017 02:26:16 -0500 X-Auth-Info: fAMBDkFswH6I8SBBz3iH1MT9aJV/tPvYV0QmwQIHtfI= Date: Thu, 5 Jan 2017 08:26:09 +0100 From: Lukasz Majewski To: Boris Brezillon Cc: Thierry Reding , Sascha Hauer , Stefan Agner , linux-pwm@vger.kernel.org, Bhuvanchandra DV , linux-kernel@vger.kernel.org, Lothar Wassmann , kernel@pengutronix.de, Fabio Estevam , Philipp Zabel Subject: Re: [PATCH v4 02/11] pwm: imx: remove ipg clock and enable per clock when required Message-ID: <20170105082609.0bd2e884@jawa> In-Reply-To: <20170105081429.32909fe1@bbrezillon> References: <1483573014-13185-1-git-send-email-lukma@denx.de> <1483573014-13185-3-git-send-email-lukma@denx.de> <20170105081429.32909fe1@bbrezillon> Organization: denx.de X-Mailer: Claws Mail 3.11.1 (GTK+ 2.24.25; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Boris, > On Thu, 5 Jan 2017 00:36:45 +0100 > Lukasz Majewski wrote: > > > From: Boris Brezillon > > Can you keep Sascha as the author of this patch? But the patch differs from the original one - and that change was sent by you - so I assume that you made the modifications. Apparently there are two authors and we only have one "Author" field :-) so I took the patch as it was sent by you. Is the rest of the series correct? Best regards, Łukasz Majewski > > > > > The use of the ipg clock was introduced with commit 7b27c160c681 > > ("pwm: i.MX: fix clock lookup"). > > In the commit message it was claimed that the ipg clock is enabled > > for register accesses. This is true for the ->config() callback, > > but not for the ->set_enable() callback. Given that the ipg clock > > is not consistently enabled for all register accesses we can assume > > that either it is not required at all or that the current code does > > not work. Remove the ipg clock code for now so that it's no longer > > in the way of refactoring the driver. > > > > In the other hand, the imx7 IP requires the peripheral clock to be > > enabled before accessing its registers. Since ->config() can be > > called when the PWM is disabled (in which case, the peripheral > > clock is also disabled), we need to surround the imx->config() with > > clk_prepare_enable(per_clk)/clk_disable_unprepare(per_clk) calls. > > > > Note that the imx7 IP was working fine so far because the ipg clock > > was actually pointing to the peripheral clock, which guaranteed > > peripheral clock activation even when ->config() was called when > > the PWM was disabled. > > > > Signed-off-by: Sascha Hauer > > Signed-off-by: Boris Brezillon > > Cc: Philipp Zabel > > --- > > Changes in v4: > > - Enable per clk before calling imx->config() > > > > Changes in v3: > > - New patch > > --- > > drivers/pwm/pwm-imx.c | 12 ++---------- > > 1 file changed, 2 insertions(+), 10 deletions(-) > > > > diff --git a/drivers/pwm/pwm-imx.c b/drivers/pwm/pwm-imx.c > > index d600fd5..b1d1e50 100644 > > --- a/drivers/pwm/pwm-imx.c > > +++ b/drivers/pwm/pwm-imx.c > > @@ -49,7 +49,6 @@ > > > > struct imx_chip { > > struct clk *clk_per; > > - struct clk *clk_ipg; > > > > void __iomem *mmio_base; > > > > @@ -206,13 +205,13 @@ static int imx_pwm_config(struct pwm_chip > > *chip, struct imx_chip *imx = to_imx_chip(chip); > > int ret; > > > > - ret = clk_prepare_enable(imx->clk_ipg); > > + ret = clk_prepare_enable(imx->clk_per); > > if (ret) > > return ret; > > > > ret = imx->config(chip, pwm, duty_ns, period_ns); > > > > - clk_disable_unprepare(imx->clk_ipg); > > + clk_disable_unprepare(imx->clk_per); > > > > return ret; > > } > > @@ -293,13 +292,6 @@ static int imx_pwm_probe(struct > > platform_device *pdev) return PTR_ERR(imx->clk_per); > > } > > > > - imx->clk_ipg = devm_clk_get(&pdev->dev, "ipg"); > > - if (IS_ERR(imx->clk_ipg)) { > > - dev_err(&pdev->dev, "getting ipg clock failed with > > %ld\n", > > - PTR_ERR(imx->clk_ipg)); > > - return PTR_ERR(imx->clk_ipg); > > - } > > - > > imx->chip.ops = &imx_pwm_ops; > > imx->chip.dev = &pdev->dev; > > imx->chip.base = -1; > Best regards, Lukasz Majewski -- DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd@denx.de