This pretty unintelligent interface is used on some RTC chips. Signed-off-by: Detlev Zundel <dzu@denx.de>master
parent
88685b5f62
commit
572e6179ad
@ -0,0 +1,46 @@ |
||||
#
|
||||
# (C) Copyright 2009
|
||||
# Detlev Zundel, DENX Software Engineering, dzu@denx.de.
|
||||
#
|
||||
# See file CREDITS for list of people who contributed to this
|
||||
# project.
|
||||
#
|
||||
# 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; either version 2 of
|
||||
# the License, or (at your option) any later version.
|
||||
#
|
||||
# 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.
|
||||
#
|
||||
# You should have received a copy of the GNU General Public License
|
||||
# along with this program; if not, write to the Free Software
|
||||
# Foundation, Inc., 59 Temple Place, Suite 330, Boston,
|
||||
# MA 02111-1307 USA
|
||||
#
|
||||
|
||||
include $(TOPDIR)/config.mk |
||||
|
||||
LIB := $(obj)libtws.a
|
||||
|
||||
COBJS-$(CONFIG_SOFT_TWS) += soft_tws.o
|
||||
|
||||
COBJS := $(COBJS-y)
|
||||
SRCS := $(COBJS:.o=.c)
|
||||
OBJS := $(addprefix $(obj),$(COBJS))
|
||||
|
||||
all: $(LIB) |
||||
|
||||
$(LIB): $(obj).depend $(OBJS) |
||||
$(AR) $(ARFLAGS) $@ $(OBJS)
|
||||
|
||||
#########################################################################
|
||||
|
||||
# defines $(obj).depend target
|
||||
include $(SRCTREE)/rules.mk |
||||
|
||||
sinclude $(obj).depend |
||||
|
||||
#########################################################################
|
@ -0,0 +1,111 @@ |
||||
/*
|
||||
* (C) Copyright 2009 |
||||
* Detlev Zundel, DENX Software Engineering, dzu@denx.de. |
||||
* |
||||
* See file CREDITS for list of people who contributed to this |
||||
* project. |
||||
* |
||||
* 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; either version 2 of |
||||
* the License, or (at your option) any later version. |
||||
* |
||||
* 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. |
||||
* |
||||
* You should have received a copy of the GNU General Public License |
||||
* along with this program; if not, write to the Free Software |
||||
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, |
||||
* MA 02111-1307 USA |
||||
* |
||||
*/ |
||||
|
||||
#define TWS_IMPLEMENTATION |
||||
#include <common.h> |
||||
|
||||
/*=====================================================================*/ |
||||
/* Public Functions */ |
||||
/*=====================================================================*/ |
||||
|
||||
/*-----------------------------------------------------------------------
|
||||
* Read bits |
||||
*/ |
||||
int tws_read(uchar *buffer, int len) |
||||
{ |
||||
int rem = len; |
||||
uchar accu, shift; |
||||
|
||||
debug("tws_read: buffer %p len %d\n", buffer, len); |
||||
|
||||
/* Configure the data pin for input */ |
||||
tws_data_config_output(0); |
||||
|
||||
/* Disable WR, i.e. setup a read */ |
||||
tws_wr(0); |
||||
udelay(1); |
||||
|
||||
/* Rise CE */ |
||||
tws_ce(1); |
||||
udelay(1); |
||||
|
||||
for (; rem > 0; ) { |
||||
for (shift = 0, accu = 0; |
||||
(rem > 0) && (shift < 8); |
||||
rem--, shift++) { |
||||
tws_clk(1); |
||||
udelay(10); |
||||
accu |= (tws_data_read() << shift); /* LSB first */ |
||||
tws_clk(0); |
||||
udelay(10); |
||||
} |
||||
*buffer++ = accu; |
||||
} |
||||
|
||||
/* Lower CE */ |
||||
tws_ce(0); |
||||
|
||||
return len - rem; |
||||
} |
||||
|
||||
|
||||
/*-----------------------------------------------------------------------
|
||||
* Write bits |
||||
*/ |
||||
int tws_write(uchar *buffer, int len) |
||||
{ |
||||
int rem = len; |
||||
uchar accu, shift; |
||||
|
||||
debug("tws_write: buffer %p len %d\n", buffer, len); |
||||
|
||||
/* Configure the data pin for output */ |
||||
tws_data_config_output(1); |
||||
|
||||
/* Enable WR, i.e. setup a write */ |
||||
tws_wr(1); |
||||
udelay(1); |
||||
|
||||
/* Rise CE */ |
||||
tws_ce(1); |
||||
udelay(1); |
||||
|
||||
for (; rem > 0; ) { |
||||
for (shift = 0, accu = *buffer++; |
||||
(rem > 0) && (shift < 8); |
||||
rem--, shift++) { |
||||
tws_data(accu & 0x01); /* LSB first */ |
||||
tws_clk(1); |
||||
udelay(10); |
||||
tws_clk(0); |
||||
udelay(10); |
||||
accu >>= 1; |
||||
} |
||||
} |
||||
|
||||
/* Lower CE */ |
||||
tws_ce(0); |
||||
|
||||
return len - rem; |
||||
} |
@ -0,0 +1,38 @@ |
||||
/*
|
||||
* (C) Copyright 2009 |
||||
* Detlev Zundel, DENX Software Engineering, dzu@denx.de. |
||||
* |
||||
* See file CREDITS for list of people who contributed to this |
||||
* project. |
||||
* |
||||
* 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; either version 2 of |
||||
* the License, or (at your option) any later version. |
||||
* |
||||
* 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. |
||||
* |
||||
* You should have received a copy of the GNU General Public License |
||||
* along with this program; if not, write to the Free Software |
||||
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, |
||||
* MA 02111-1307 USA |
||||
* |
||||
*/ |
||||
|
||||
#ifndef _TWS_H_ |
||||
#define _TWS_H_ |
||||
|
||||
/*
|
||||
* Read/Write interface: |
||||
* buffer: Where to read/write the data |
||||
* len: How many bits to read/write |
||||
* |
||||
* Returns: 0 on success, not 0 on failure |
||||
*/ |
||||
int tws_read(uchar *buffer, int len); |
||||
int tws_write(uchar *buffer, int len); |
||||
|
||||
#endif /* _TWS_H_ */ |
Loading…
Reference in new issue