Messages in this thread | | | Date | Wed, 5 Nov 2014 12:41:34 +0100 | From | Mike Looijmans <> | Subject | Re: [PATCH v3] Add ltc3562 voltage regulator driver |
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On 11/04/2014 09:26 PM, Mark Brown wrote: > On Tue, Nov 04, 2014 at 07:50:45AM +0100, Mike Looijmans wrote: > >> v3: Add .of_match_table and prefix lltc >> Clarify why regmap cannot be used >> Add lltc,operating-mode (0..3) DT property >> regulator child nodes are optional > > Leave out the mode setting in the DT for now please, Javier was looking > at adding a standard property for this with a driver defined mapping to > modes - you should implement the standard get_mode() and set_mode() (but > can always do that as a followup). > >> +/* the LTC3562 does not have a register map, instead it receives a two-byte >> + * command set. The first byte sets the mask for the output(s) to be programmed >> + * and the second byte hold the "enable" bit and the DAC code. */ >> +struct ltc3562_status { >> + u8 addr_mode; /* sub-address byte: program mask an operating mode */ >> + u8 enable_daccode; /* data byte: Enable bit and DAC code */ >> +}; > > So, I managed to find a datasheet[1] and this does actually seem to be a > standard register map. It looks like this is a 4x12 register map with > the program bytes being essentially register addresses (called sub > addresses in the datasheet), two pad bits (normally we'd include these > in the data for convenience) and the rest of the bits data. What am I > missing here? > > Otherwise this looks good. > > [1] http://cds.linear.com/docs/en/datasheet/3562fa.pdf >
Things that makes me think it's NOT a register map: - You cannot read from the device - You always have to send a complete command set (two bytes) - There is data (the regulator mode) in the address byte - The 'address' is not an index but a bitmask in bits 4..7
Yeah, I think you can force-feed this to regmap. It will just make the code considerably bigger and harder to understand, and as far as I know, the one and only advantage this will bring is that you can dump the current "registers" (4x10 bits of data) via /sys/kernel/debug/regmap.
I fail to see the use for regmap here, but if your view on this is "regmap or burst" then I'll implement it.
Mike.
Met vriendelijke groet / kind regards,
Mike Looijmans System Expert
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