hello
I'm not sure if this is the correct place to be asking this, if there is
a better place please redirect me.
I'm currently working on a kernel driver for the Texas Instruments
tps92518-Q1 and tps92518HV-Q1.
This device uses 16-bit SPI Frames (7-bit control, 9-bit data).
is "Command Frame"
|1-bit command bit 5-bit Address 1-bit parity 9-bit data|
requires a parity bit
|PARITY = XNOR(CMD, A4..A0, D8..D0)|
I'm trying to use regmaps where possible and I can define a regmap, e.g.
|static struct regmap_config tps92518_regmap_config = { .reg_bits = 6,
.pad_bits = 1, // parity bit .val_bits = 9, .max_register =
tps92518_RESET, }; |
however so far i cannot currently see how to automatically calculate it
without replacing large chunks of code
e.g replacing chunks of /drivers/base/regmap/regmap-spi.c with a new
regmap_bus
some where i need to be able to calculate and insert a parity bit
is there anywhere i can setup a callback that preprocesses the spi
frames before sending?
I'm working up the chain an i can see a potential patch to regmaps that
would fix this if nothing better already exists
with regmap_config exists /@read_flag_mask/ and /@write_flag_mask/,
along the same line there could be added a "@read_parity_mask" and
"@write_parity_mask"
and an optional "@reg_parity" callback that calculates the parity
from/reg/ and /val/ similar/@reg_read/ and /@reg_write/ but without
replacing the entire read/write operations
I may even be able to write this but that is outside the spi-subsystem,
and i'm currently not sure what list regmaps fall under
i apologise if this is the wrong list and, thankyou for any responses
kind regards
christopher tyerman
