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device: Add i2c read/write register field API 

i2c_read_field() - read the value from the specific register field
i2c_write_field() - write the value to the specific register field

BRANCH=none
BUG=none
TEST=none

Change-Id: I2098715b4583c1936c93b3ff45ec330910964304
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: 0817fc76d07491b39c066f1393a6435f0831b50c
Original-Change-Id: I92c187a89d10cfcecf3dfd9291e0bc015459c393
Original-Signed-off-by: Yidi Lin <yidi.lin@mediatek.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/332712
Original-Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/14105
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-by: Martin Roth <martinroth@google.com>
This commit is contained in:
Yidi Lin 2016-03-15 14:38:44 +08:00 committed by Martin Roth
parent f7d4f73053
commit d33ebd1374
3 changed files with 56 additions and 0 deletions
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5
src/device/Makefile.inc
View File

@ -31,3 +31,8 @@ bootblock-$(CONFIG_SOFTWARE_I2C) += software_i2c.c
verstage-$(CONFIG_SOFTWARE_I2C) += software_i2c.c
romstage-$(CONFIG_SOFTWARE_I2C) += software_i2c.c
ramstage-$(CONFIG_SOFTWARE_I2C) += software_i2c.c
bootblock-y += i2c.c
verstage-y += i2c.c
romstage-y += i2c.c
ramstage-y += i2c.c

46
src/device/i2c.c Normal file
View File

@ -0,0 +1,46 @@
/*
* This file is part of the coreboot project.
*
* Copyright 2016 MediaTek Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <device/i2c.h>
int i2c_read_field(unsigned bus, uint8_t chip, uint8_t reg, uint8_t *data,
uint8_t mask, uint8_t shift)
{
int ret;
uint8_t buf = 0;
ret = i2c_readb(bus, chip, reg, &buf);
buf &= (mask << shift);
*data = (buf >> shift);
return ret;
}
int i2c_write_field(unsigned bus, uint8_t chip, uint8_t reg, uint8_t data,
uint8_t mask, uint8_t shift)
{
int ret;
uint8_t buf = 0;
ret = i2c_readb(bus, chip, reg, &buf);
buf &= ~(mask << shift);
buf |= (data << shift);
ret |= i2c_writeb(bus, chip, reg, buf);
return ret;
}

5
src/include/device/i2c.h
View File

@ -45,6 +45,11 @@ void software_i2c_wedge_ack(unsigned bus, u8 chip);
void software_i2c_wedge_read(unsigned bus, u8 chip, u8 reg, int bit_count);
void software_i2c_wedge_write(unsigned bus, u8 chip, u8 reg, int bit_count);
int i2c_read_field(unsigned bus, uint8_t chip, uint8_t reg, uint8_t *data,
uint8_t mask, uint8_t shift);
int i2c_write_field(unsigned bus, uint8_t chip, uint8_t reg, uint8_t data,
uint8_t mask, uint8_t shift);
/*
* software_i2c is supposed to be a debug feature. It's usually not compiled in,
* but when it is it can be dynamically enabled at runtime for certain busses.