Re: NVMEM usage question
On Mon, 14 Mar 2016, Eddie Huang wrote: > > Mediatek PMIC chip have some spare registers used to store information. > The value of these registers will exist until user unplug battery or > battery depletion. One of our usage example is store battery utilization i.e. like battery-backed raid caches. > in these spare registers. We want to implement NVMEM driver to > read/write sparse registers, but binding document describe NVMEM is for > "Non-volatile memory", and for hardware like eeprom, efuse. Since the Users will expect nvmem to not go away on battery drain, so I don't think it would be the best fit, semantically speaking. Unless this is common enough that it would make sense to have a generic quasi-non-volatile profile for nvmem, and publish that constraint to userspace in a standard way... -- "One disk to rule them all, One disk to find them. One disk to bring them all and in the darkness grind them. In the Land of Redmond where the shadows lie." -- The Silicon Valley Tarot Henrique Holschuh
Re: NVMEM usage question
On Mon, 14 Mar 2016, Eddie Huang wrote: > > Mediatek PMIC chip have some spare registers used to store information. > The value of these registers will exist until user unplug battery or > battery depletion. One of our usage example is store battery utilization i.e. like battery-backed raid caches. > in these spare registers. We want to implement NVMEM driver to > read/write sparse registers, but binding document describe NVMEM is for > "Non-volatile memory", and for hardware like eeprom, efuse. Since the Users will expect nvmem to not go away on battery drain, so I don't think it would be the best fit, semantically speaking. Unless this is common enough that it would make sense to have a generic quasi-non-volatile profile for nvmem, and publish that constraint to userspace in a standard way... -- "One disk to rule them all, One disk to find them. One disk to bring them all and in the darkness grind them. In the Land of Redmond where the shadows lie." -- The Silicon Valley Tarot Henrique Holschuh
Re: NVMEM usage question
On 14/03/16 12:01, Eddie Huang wrote: Hi, Mediatek PMIC chip have some spare registers used to store information. The value of these registers will exist until user unplug battery or battery depletion. One of our usage example is store battery utilization in these spare registers. We want to implement NVMEM driver to read/write sparse registers, but binding document describe NVMEM is for "Non-volatile memory", and for hardware like eeprom, efuse. Since the usage here is some kind of "battery backup memory", but not real non-volatile memory, is NVMEM driver suitable for this case ? If this battery usage information can be retrieved after full power cycle, then there should be some sort of non volatile memory involved. If that's the case then you can use the nvmem. --srini Eddie
Re: NVMEM usage question
On 14/03/16 12:01, Eddie Huang wrote: Hi, Mediatek PMIC chip have some spare registers used to store information. The value of these registers will exist until user unplug battery or battery depletion. One of our usage example is store battery utilization in these spare registers. We want to implement NVMEM driver to read/write sparse registers, but binding document describe NVMEM is for "Non-volatile memory", and for hardware like eeprom, efuse. Since the usage here is some kind of "battery backup memory", but not real non-volatile memory, is NVMEM driver suitable for this case ? If this battery usage information can be retrieved after full power cycle, then there should be some sort of non volatile memory involved. If that's the case then you can use the nvmem. --srini Eddie
NVMEM usage question
Hi, Mediatek PMIC chip have some spare registers used to store information. The value of these registers will exist until user unplug battery or battery depletion. One of our usage example is store battery utilization in these spare registers. We want to implement NVMEM driver to read/write sparse registers, but binding document describe NVMEM is for "Non-volatile memory", and for hardware like eeprom, efuse. Since the usage here is some kind of "battery backup memory", but not real non-volatile memory, is NVMEM driver suitable for this case ? Eddie
NVMEM usage question
Hi, Mediatek PMIC chip have some spare registers used to store information. The value of these registers will exist until user unplug battery or battery depletion. One of our usage example is store battery utilization in these spare registers. We want to implement NVMEM driver to read/write sparse registers, but binding document describe NVMEM is for "Non-volatile memory", and for hardware like eeprom, efuse. Since the usage here is some kind of "battery backup memory", but not real non-volatile memory, is NVMEM driver suitable for this case ? Eddie
