On Tue, 24 Oct 2017, Steve Twiss wrote: > Hi Lee, > > On 24 October 2017 11:25, Lee Jones wrote: > > > Subject: Re: [PATCH 2/6] mfd: da9062: make register CONFIG_I writable > > > > On Tue, 17 Oct 2017, Michael Grzeschik wrote: > > > From: Stefan Christ <s.christ@xxxxxxxxx> > > > > > > Make the config register CONFIG_I writable to change the watchdog mode. > > > The datasheet does not mention exactly whether these registers should be > > > read-only or writeable. But writing to those registers works at runtime. > > > Only on reset they are reseted. > > > > > > Signed-off-by: Stefan Christ <s.christ@xxxxxxxxx> > > > Signed-off-by: Christian Hemp <c.hemp@xxxxxxxxx> > > > --- > > > drivers/mfd/da9062-core.c | 4 ++++ > > > 1 file changed, 4 insertions(+) > > > > For my own reference: > > Acked-for-MFD-by: Lee Jones <lee.jones@xxxxxxxxxx> > > Setting CONFIG_I to be writable (and allowing WATCHDOG_SD bit changes to that register) > is probably not a great idea. On the face of it, the change is fairly innocuous but it will > allow the PMIC's behaviour to be modified during kernel run-time. > > That change can be done, but making it a permanent change in the general Linux kernel driver > would indicate it is okay to change the CONFIG_I registers during normal run-time operation, > and generally I do not think this is okay. > > - [PATCH 3/6] watchdog: da9062: reset board on watchdog timeout > https://www.spinics.net/lists/linux-watchdog/msg12680.html > > I suggested if CONFIG_I is to be altered, then this register could be modified before the > Linux kernel driver has started, e.g. early in the bootloader; or the change chould be done > in hardware by writing the persistent OTP in the device. If necessary, the Linux kernel driver > can read the CONFIG_I register and modify its behaviour accordingly. In both cases, a write > access change to CONFIG_I would not be needed. Understood. Thanks Steve. Ack revoked. -- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog -- To unsubscribe from this list: send the line "unsubscribe linux-watchdog" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
