From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751293AbdA2V5f (ORCPT ); Sun, 29 Jan 2017 16:57:35 -0500 Received: from mail-out.m-online.net ([212.18.0.9]:41916 "EHLO mail-out.m-online.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750855AbdA2VzI (ORCPT ); Sun, 29 Jan 2017 16:55:08 -0500 X-Auth-Info: pTRTpxllZPjRHbS+6JcL891PmiPyUf+1nXOgZkI5SwQ= From: Lukasz Majewski To: Thierry Reding , Sascha Hauer , Stefan Agner , Boris Brezillon , linux-pwm@vger.kernel.org, Bhuvanchandra DV , linux-kernel@vger.kernel.org Cc: Lothar Wassmann , kernel@pengutronix.de, Fabio Estevam , Philipp Zabel Subject: [PATCH v5 02/11] pwm: imx: remove ipg clock and enable per clock when required Date: Sun, 29 Jan 2017 22:54:06 +0100 Message-Id: <1485726855-16236-3-git-send-email-lukma@denx.de> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1485726855-16236-1-git-send-email-lukma@denx.de> References: <1485726855-16236-1-git-send-email-lukma@denx.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sascha Hauer 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. On 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 driver was working fine for the i.MX 7 IP so far because the ipg and peripheral clock use the same hardware clock gate, 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 Reviewed-by: Stefan Agner Tested-by: Stefan Agner --- Changes in v5: - Minor edit of commmit message 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; -- 2.1.4