From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Agner Subject: Re: [PATCH v2 1/3] power: reset: read priority from device tree Date: Mon, 01 Dec 2014 18:24:37 +0100 Message-ID: References: <1417453389-1588-1-git-send-email-stefan@agner.ch> <1417453389-1588-2-git-send-email-stefan@agner.ch> <20141201171126.GB22708@leverpostej> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20141201171126.GB22708@leverpostej> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Mark Rutland Cc: shawn.guo-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org, linux-0h96xk9xTtrk1uMJSBkQmQ@public.gmane.org, arnd-r2nGTMty4D4@public.gmane.org, sre-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, fkan-qTEPVZfXA3Y@public.gmane.org, grant.likely-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, dbaryshkov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: devicetree@vger.kernel.org On 2014-12-01 18:11, Mark Rutland wrote: > On Mon, Dec 01, 2014 at 05:03:07PM +0000, Stefan Agner wrote: >> This patch adds an optional property which allows to specify the >> reset source priority. This priority is used by the kernel restart >> handler call chain to sort out the proper reset/restart method. >> Depending on the power design of a board or other machine/board >> specific peculiarity, it is not possible to pick a generic priority. >> >> Signed-off-by: Stefan Agner >> --- >> Documentation/devicetree/bindings/power/reset/syscon-reboot.txt | 3 +++ >> drivers/power/reset/syscon-reboot.c | 5 ++++- >> 2 files changed, 7 insertions(+), 1 deletion(-) >> >> diff --git a/Documentation/devicetree/bindings/power/reset/syscon-reboot.txt b/Documentation/devicetree/bindings/power/reset/syscon-reboot.txt >> index 1190631..ee41d9c 100644 >> --- a/Documentation/devicetree/bindings/power/reset/syscon-reboot.txt >> +++ b/Documentation/devicetree/bindings/power/reset/syscon-reboot.txt >> @@ -11,6 +11,9 @@ Required properties: >> - offset: offset in the register map for the reboot register (in bytes) >> - mask: the reset value written to the reboot register (32 bit access) >> >> +Optional properties: >> +- priority: define the priority of the reset (0-255, defaults to 128) >> + > > NAK. This is a leak of Linux-internal details. > > What is this necessary for? > > Mark. Hi Mark, In my case, it is necessary to be called ahead of the watchdog, which has a priority of 128. This syscon-reboot driver currently has a default priority of 128 too. I could live with a higher default priority for the syscon-reboot driver, in fact I proposed that in the discussion of v1 of that patch: https://lkml.org/lkml/2014/11/28/484 IMHO, this priority might make sense for most cases, I guess that dedicated "syscon" capabilities are usually better suited as a reboot source than watchdog. If dt, then the question which arises: If there are different capabilities to reset/reboot a whole system, how do we reflect which is the best suited one in dt? -- Stefan > >> Default will be little endian mode, 32 bit access only. >> >> Examples: >> diff --git a/drivers/power/reset/syscon-reboot.c b/drivers/power/reset/syscon-reboot.c >> index 815b901..3060d6b 100644 >> --- a/drivers/power/reset/syscon-reboot.c >> +++ b/drivers/power/reset/syscon-reboot.c >> @@ -67,8 +67,11 @@ static int syscon_reboot_probe(struct platform_device *pdev) >> if (of_property_read_u32(pdev->dev.of_node, "mask", &ctx->mask)) >> return -EINVAL; >> >> - ctx->restart_handler.notifier_call = syscon_restart_handle; >> ctx->restart_handler.priority = 128; >> + of_property_read_u32(pdev->dev.of_node, "priority", >> + &ctx->restart_handler.priority); >> + >> + ctx->restart_handler.notifier_call = syscon_restart_handle; >> err = register_restart_handler(&ctx->restart_handler); >> if (err) >> dev_err(dev, "can't register restart notifier (err=%d)\n", err); >> -- >> 2.1.3 >> >> -- >> To unsubscribe from this list: send the line "unsubscribe devicetree" in >> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html