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[155.4.129.234]) by smtp.gmail.com with ESMTPSA id j19sm3342054lfb.15.2021.03.17.02.31.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 17 Mar 2021 02:31:37 -0700 (PDT) From: Ulf Hansson To: Shawn Guo , Dong Aisheng , Sascha Hauer Cc: Liu Ying , Peng Fan , NXP Linux Team , Ulf Hansson , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH] firmware: imx: scu-pd: Update comments for single global power domain Date: Wed, 17 Mar 2021 10:31:17 +0100 Message-Id: <20210317093117.16091-1-ulf.hansson@linaro.org> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Since the introduction of the PM domain support for the scu-pd, the genpd framework has been continuously improved. More preciously, using a single global power domain can quite easily be deployed for imx platforms. To avoid confusions, let's therefore make an update to the comments about the missing pieces. Signed-off-by: Ulf Hansson --- drivers/firmware/imx/scu-pd.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/firmware/imx/scu-pd.c b/drivers/firmware/imx/scu-pd.c index 08533ee67626..6e178a63442d 100644 --- a/drivers/firmware/imx/scu-pd.c +++ b/drivers/firmware/imx/scu-pd.c @@ -29,6 +29,10 @@ * The framework needs some proper extension to support multi power * domain cases. * + * Update: Genpd assigns the ->of_node for the virtual device before it + * invokes ->attach_dev() callback, hence parsing for device resources via + * DT should work fine. + * * 2. It also breaks most of current drivers as the driver probe sequence * behavior changed if removing ->power_on|off() callback and use * ->start() and ->stop() instead. genpd_dev_pm_attach will only power @@ -39,8 +43,11 @@ * domain enabled will trigger a HW access error. That means we need fix * most drivers probe sequence with proper runtime pm. * - * In summary, we need fix above two issue before being able to switch to - * the "single global power domain" way. + * Update: Runtime PM support isn't necessary. Instead, this can easily be + * fixed in drivers by adding a call to dev_pm_domain_start() during probe. + * + * In summary, the second part needs to be addressed via minor updates to the + * relevant drivers, before the "single global power domain" model can be used. * */ -- 2.25.1