On Wed, Mar 28, 2018 at 8:14 AM, Tim Harvey <tharvey@xxxxxxxxxxxxx> wrote: > The Gateworks System Controller (GSC) is an I2C slave controller > implemented with an MSP430 micro-controller whose firmware embeds the > following features: > - I/O expander (16 GPIO's) using PCA955x protocol > - Real Time Clock using DS1672 protocol > - User EEPROM using AT24 protocol > - HWMON using custom protocol > - Interrupt controller with tamper detect, user pushbotton > - Watchdog controller capable of full board power-cycle > - Power Control capable of full board power-cycle > > see http://trac.gateworks.com/wiki/gsc for more details > <snip> > + > +/* > + * gsc_powerdown - API to use GSC to power down board for a specific time > + * > + * secs - number of seconds to remain powered off > + */ > +static int gsc_powerdown(struct gsc_dev *gsc, unsigned long secs) > +{ > + int ret; > + unsigned char regs[4]; > + > + dev_info(&gsc->i2c->dev, "GSC powerdown for %ld seconds\n", > + secs); > + regs[0] = secs & 0xff; > + regs[1] = (secs >> 8) & 0xff; > + regs[2] = (secs >> 16) & 0xff; > + regs[3] = (secs >> 24) & 0xff; > + ret = regmap_bulk_write(gsc->regmap, GSC_TIME_ADD, regs, 4); > + > + return ret; > +} Any feedback on the 'powerdown' sysfs attribute that hooks to this function? This allows the GSC to disable the board primary power supply for 2^32 seconds and is often used to 'reset' the board although it could also be used to put the board in a power down state longer. I'm wondering if there is a more appropriate API for this in the kernel that I don't know about. I would also like to register a restart handler using this but I believe that ARM restart handlers currently can not use I2C - is that correct? Regards, Tim -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
