[PATCH V3 2/2] nvmem: add generic driver for devices with MMIO access

Rafał Miłecki rafal at milecki.pl
Mon Feb 20 14:05:01 PST 2023


On 2023-02-20 20:55, Randy Dunlap wrote:
> On 2/20/23 09:49, Rafał Miłecki wrote:
>> +static int mmio_nvmem_write(void *context, unsigned int offset, void 
>> *val, size_t bytes)
>> +{
>> +	struct mmio_nvmem *priv = context;
>> +
>> +	switch (priv->io_width) {
>> +	case 1:
>> +	case 2:
>> +	case 4:
>> +		return -EOPNOTSUPP;
> 
> I'm just curious: (since read supports those cases)
> 
> what size writes are typically used here?
> And what value for priv->io_width?

Sorry, I really don't have any statistics on this or any real overview
of hardware that supports MMIO writes. It's probably a minority of
devices that allows it.



More information about the linux-arm-kernel mailing list