This pretty unintelligent interface is used on some RTC chips.
Signed-off-by: Detlev Zundel dzu@denx.de --- Makefile | 3 +- drivers/twserial/Makefile | 46 ++++++++++++++++++ drivers/twserial/soft_tws.c | 110 +++++++++++++++++++++++++++++++++++++++++++ include/tws.h | 47 ++++++++++++++++++ 4 files changed, 205 insertions(+), 1 deletions(-) create mode 100644 drivers/twserial/Makefile create mode 100644 drivers/twserial/soft_tws.c create mode 100644 include/tws.h
diff --git a/Makefile b/Makefile index 63b9909..7c37845 100644 --- a/Makefile +++ b/Makefile @@ -1,5 +1,5 @@ # -# (C) Copyright 2000-2008 +# (C) Copyright 2000-2009 # Wolfgang Denk, DENX Software Engineering, wd@denx.de. # # See file CREDITS for list of people who contributed to this @@ -262,6 +262,7 @@ TAG_SUBDIRS += cpu/mpc8xxx endif LIBS += drivers/rtc/librtc.a LIBS += drivers/serial/libserial.a +LIBS += drivers/twserial/libtws.a LIBS += drivers/usb/libusb.a LIBS += drivers/video/libvideo.a LIBS += common/libcommon.a diff --git a/drivers/twserial/Makefile b/drivers/twserial/Makefile new file mode 100644 index 0000000..0b059f3 --- /dev/null +++ b/drivers/twserial/Makefile @@ -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 + +######################################################################### diff --git a/drivers/twserial/soft_tws.c b/drivers/twserial/soft_tws.c new file mode 100644 index 0000000..f63fc3f --- /dev/null +++ b/drivers/twserial/soft_tws.c @@ -0,0 +1,110 @@ +/* + * (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; +} diff --git a/include/tws.h b/include/tws.h new file mode 100644 index 0000000..bfa8d58 --- /dev/null +++ b/include/tws.h @@ -0,0 +1,47 @@ +/* + * (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_ + +#ifndef TWS_SOFT_DECLARATIONS +# if defined(CONFIG_MPC5xxx) +# define TWS_SOFT_DECLARATIONS \ + volatile ioport_t *iop = ioport_addr((immap_t *)CONFIG_SYS_IMMR, I2C_PORT); +# else +# define TWS_SOFT_DECLARATIONS +# endif +#endif + +/* + * 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_ */