From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Courbot Date: Fri, 17 Aug 2012 08:54:32 +0000 Subject: Re: [PATCH v4 0/3] Runtime Interpreted Power Sequences Message-Id: <502E06C8.8090508@nvidia.com> List-Id: References: <1345097337-24170-1-git-send-email-acourbot@nvidia.com> <201208162347.34810.rjw@sisk.pl> In-Reply-To: <201208162347.34810.rjw@sisk.pl> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: "Rafael J. Wysocki" Cc: Stephen Warren , Thierry Reding , Simon Glass , Grant Likely , Rob Herring , Mark Brown , Anton Vorontsov , David Woodhouse , Arnd Bergmann , Leela Krishna Amudala , "linux-tegra@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-fbdev@vger.kernel.org" , "devicetree-discuss@lists.ozlabs.org" , "linux-doc@vger.kernel.org" On 08/17/2012 06:47 AM, Rafael J. Wysocki wrote: > On Thursday, August 16, 2012, Alexandre Courbot wrote: >> Overdue revision of this new feature, some changes required additional thought >> and rework. >> >> The most important change is in the way power sequences are expressed in the >> device tree. In order to avoid having to specify #address-cells, #size-cells and >> reg properties, the @ notation in the step names is dropped, and instead a >> fixed, sequential naming is adopted. The type of the resource used by a step is >> decided by the presence of some recognized properties: >> >> power-on-sequence { >> step0 { >> regulator = "power"; >> enable; >> }; >> step1 { >> delay = <10000>; >> }; >> step2 { >> pwm = "backlight"; >> enable; >> }; >> ... >> >> To me this looks safe, clear and close to the platform data representation, but >> needs approval from DT experts. >> >> Resources are still referenced by name instead of having their phandles defined >> directly inside the sequences, as previous discussion came to the conclusion >> that doing so would require controversial changes to the regulator and PWM >> frameworks, and that having the resources declared at the device level was >> making sense logically speaking. >> >> Other changes/fixes since last revision: >> * Move to drivers/power/ (hope this is ok with the maintainers?) >> * Use microseconds for delay >> * Use devm for PWM resources and remove cleanup function as all resources are >> devm-managed >> * Remove "-gpio" suffix for GPIO reference in the driver >> * Remove params structure >> * Make power_seq structure private >> * Number of steps in a sequence is explicitly stated instead of resorting to a >> "stop" sequence step >> * Delays are a step instead of being a step parameter >> * Use flexible member arrays to limit number of memory allocations >> * Add documentation to DT bindings >> >> There was a lot of feedback on the previous version (thanks!) so if I forgot >> to address some important point, please bring it to my attention again. >> >> Alexandre Courbot (3): >> Runtime Interpreted Power Sequences >> pwm_backlight: use power sequences >> tegra: add pwm backlight device tree nodes > > May I ask that the next version of this patchset be CCed to > linux-pm@vger.kernel.org? Will do. Alex.