Re: [RFC/RFT PATCH 1/3] Input: ad7879 - convert to use regmap

From: Michael Hennerich
Date: Mon Feb 20 2017 - 11:08:47 EST

On 18.02.2017 00:31, Dmitry Torokhov wrote:
Instead of rolling our own infrastructure to provide uniform access to I2C
and SPI buses, let's switch to using regmap.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>


I am a bit (actually a lot) confused how this driver was working with SPI
and Blackfin, which is, as far as I understand, little-endian, because from
my reading of the spec the data on wire is big-endian. If this is not
correct we need to change spi regmap config to be:

static const struct regmap_config ad7879_spi_regmap_config = {
.reg_bits = 16,
.val_bits = 16,
.max_register = 15,
.read_flag_mask = AD7879_CMD_MAGIC | AD7879_CMD_READ,
.write_flag_mask = AD7879_CMD_MAGIC,
.reg_format_endian_default = REGMAP_ENDIAN_LITTLE,
.val_format_endian_default = REGMAP_ENDIAN_LITTLE,

Also, the original ad7879_spi_xfer was funky to tell the least. We
allocated n+2 spi_transfer structures, then smashed the beginning of the
first one with u16 command, then basically "restored" it???

Anyway, if you could try it out (and fix ;) ), that would be great.

Hi Dimitry,

Thanks for doing this.
Overall looks great, but i definitely need to test this.
Your right this xfer functions looks awkward.
I'll review and get back to you.


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