Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752567AbdI0Ktt (ORCPT ); Wed, 27 Sep 2017 06:49:49 -0400 Received: from lelnx193.ext.ti.com ([198.47.27.77]:41563 "EHLO lelnx193.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752455AbdI0Ktr (ORCPT ); Wed, 27 Sep 2017 06:49:47 -0400 Subject: Re: [PATCH v3 5/5] mtd: spi-nor: cadence-quadspi: Add runtime PM support To: CC: Marek Vasut , Cyrille Pitchen , David Woodhouse , Brian Norris , Boris Brezillon , Rob Herring , , , , linux-arm-kernel References: <20170924105924.23923-1-vigneshr@ti.com> <20170924105924.23923-6-vigneshr@ti.com> <3a1160f9-a0ae-c84c-d209-af97c3c3b0f6@gmail.com> <4ee69ea4-14cc-4305-bf3f-8fe76d43bf6b@ti.com> <038919d3-ff32-d0a7-4c0a-3be16436052d@ti.com> From: Vignesh R Message-ID: <7237fa9e-4d3a-8a82-10c6-76737c23ed6f@ti.com> Date: Wed, 27 Sep 2017 16:18:49 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 8bit X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1718 Lines: 55 Hi Matthew, On Tuesday 26 September 2017 05:19 AM, Marek Vasut wrote: [...] >>>> Ok thanks! Do you know if pm_runtime_get_sync() can enable clocks for >>>> QSPI on SoCFPGA or if clk_prepare_enable() is needed? Just trying to see >>>> if its possible to get rid of clk_*() calls in favor of pm_*() calls. >>> >>> Not of the top of my head, sorry. +CC Matthew, he should know. >> >> I am not an expert at the clock framework nor the power management, but I >> did ask around a bit.  No one I asked was planning to change the clk_*() >> calls to pm_*() call, but the feedback was that it would be a good idea. > > The question is, if we do the replacement, will it break on socfpga ? > A quick test might be useful. > yes, a quick qspi test with clk_prepare_enable() replaced by pm_*() calls like below patch would be helpful: diff --git a/drivers/mtd/spi-nor/cadence-quadspi.c b/drivers/mtd/spi-nor/cadence-quadspi.c index 53c7d8e0327a..7ad3e176cc88 100644 --- a/drivers/mtd/spi-nor/cadence-quadspi.c +++ b/drivers/mtd/spi-nor/cadence-quadspi.c @@ -34,6 +34,7 @@ #include #include #include +#include #define CQSPI_NAME "cadence-qspi" #define CQSPI_MAX_CHIPSELECT 16 @@ -1206,11 +1207,8 @@ static int cqspi_probe(struct platform_device *pdev) return -ENXIO; } - ret = clk_prepare_enable(cqspi->clk); - if (ret) { - dev_err(dev, "Cannot enable QSPI clock.\n"); - return ret; - } + pm_runtime_enable(dev); + pm_runtime_get_sync(dev); cqspi->master_ref_clk_hz = clk_get_rate(cqspi->clk); -- Regards Vignesh