linux-kernel - [RFC PATCH v2 0/5] regmap: Add Parity bit Calculation to regmaps

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Message-Id: <20211222184340.1907240-1-linuxkernel@fbautosys.co.uk>
Date:   Wed, 22 Dec 2021 18:43:35 +0000
From:   linuxkernel@...utosys.co.uk
To:     linux-kernel@...r.kernel.org
Cc:     broonie@...nel.org
Subject: [RFC PATCH v2 0/5] regmap: Add Parity bit Calculation to regmaps

From: Christopher Tyerman <c.tyerman@...ebladeautomationsystems.co.uk>

this patch set adds parity bit calculation to regmaps

this allow support for devices that require parity bits in their
communications.

e.g. the texas instruments TPS92518-Q1 which requires a parity bit in the
7th bit of a 16 bit spi frame
or the TPS92518-Q1 which requires a parity bit in the 1st bit of a 16 bit
spi frame

parity aimed to work devices where parity in reg block
e.g. TPS65311-Q1 and TPS92518-Q1

TPS65311-Q1 frame format	[PWRRRRRRDDDDDDDD]
TPS92518-Q1	frame format	[WRRRRRPDDDDDDDDD]
P - parity bit, W - Read/Write bit, R - register, D -register data

TPS65311-Q1 parity mask 0x8000 (1000000000000000)
TPS92518-Q1	parity mask	0x0200 (0000001000000000)


calculates parity bit based up parity function defined by
regmap_config->parity_calc

regmap_config->parity_calc defaults to regmap_parity_calc_even()

adds alternate parity function regmap_parity_calc_odd()

calculates parity bit for writes if regmap_config->parity_write_mask is > 0
calculates parity bit for reads if regmap_config->parity_read_mask is > 0

parity is not calculated when bus implements reg_update_bits()


Altered the regmap_format_X_X_write functions to account for padding bits
allowing masks to write to either end of register address for formatted writes

Altered formatted_write to apply write and parity masks

Added parsers for 9 bit data format which are written by formatted write

Christopher Tyerman (5):
  Add Parity bit Calculation to regmaps
  Altered regmap_format_X_X_write functions to account for padding bits
  Added setting of writemap to formatted write
  Add Parity Calculation to formatted write
  Add parser for X_9 formats

 drivers/base/regmap/internal.h |   6 +
 drivers/base/regmap/regmap.c   | 259 +++++++++++++++++++++++++++++++--
 include/linux/regmap.h         |  32 ++++
 3 files changed, 287 insertions(+), 10 deletions(-)


base-commit: 02d6fdecb9c38de19065f6bed8d5214556fd061d
-- 
2.25.1