drivers/twserial: Add protocol driver for "three wire serial" interface.

This pretty unintelligent interface is used on some RTC chips. Signed-off-by: Detlev Zundel <dzu@denx.de>

drivers/twserial: Add protocol driver for "three wire serial" interface.
This pretty unintelligent interface is used on some RTC chips. Signed-off-by: Detlev Zundel <dzu@denx.de>
Detlev Zundel · Wolfgang Denk
1 parent 88685b5f62
Showing 4 changed files with 197 additions and 1 deletions Side-by-side Diff
Makefile
drivers/twserial/Makefile
drivers/twserial/soft_tws.c
include/tws.h
 #
-# (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 @@
 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
+#
+# (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
+
+#########################################################################
+/*
+ * (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;
+}
+/*
+ * (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_ */
1	1	#
2		-# (C) Copyright 2000-2008
	2	+# (C) Copyright 2000-2009
3	3	# Wolfgang Denk, DENX Software Engineering, wd@denx.de.
4	4	#
5	5	# See file CREDITS for list of people who contributed to this
...	...	@@ -262,6 +262,7 @@
262	262	endif
263	263	LIBS += drivers/rtc/librtc.a
264	264	LIBS += drivers/serial/libserial.a
	265	+LIBS += drivers/twserial/libtws.a
265	266	LIBS += drivers/usb/libusb.a
266	267	LIBS += drivers/video/libvideo.a
267	268	LIBS += common/libcommon.a
	1	+#
	2	+# (C) Copyright 2009
	3	+# Detlev Zundel, DENX Software Engineering, dzu@denx.de.
	4	+#
	5	+# See file CREDITS for list of people who contributed to this
	6	+# project.
	7	+#
	8	+# This program is free software; you can redistribute it and/or
	9	+# modify it under the terms of the GNU General Public License as
	10	+# published by the Free Software Foundation; either version 2 of
	11	+# the License, or (at your option) any later version.
	12	+#
	13	+# This program is distributed in the hope that it will be useful,
	14	+# but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	16	+# GNU General Public License for more details.
	17	+#
	18	+# You should have received a copy of the GNU General Public License
	19	+# along with this program; if not, write to the Free Software
	20	+# Foundation, Inc., 59 Temple Place, Suite 330, Boston,
	21	+# MA 02111-1307 USA
	22	+#
	23	+
	24	+include $(TOPDIR)/config.mk
	25	+
	26	+LIB := $(obj)libtws.a
	27	+
	28	+COBJS-$(CONFIG_SOFT_TWS) += soft_tws.o
	29	+
	30	+COBJS := $(COBJS-y)
	31	+SRCS := $(COBJS:.o=.c)
	32	+OBJS := $(addprefix $(obj),$(COBJS))
	33	+
	34	+all: $(LIB)
	35	+
	36	+$(LIB): $(obj).depend $(OBJS)
	37	+ $(AR) $(ARFLAGS) $@ $(OBJS)
	38	+
	39	+#########################################################################
	40	+
	41	+# defines $(obj).depend target
	42	+include $(SRCTREE)/rules.mk
	43	+
	44	+sinclude $(obj).depend
	45	+
	46	+#########################################################################
	1	+/*
	2	+ * (C) Copyright 2009
	3	+ * Detlev Zundel, DENX Software Engineering, dzu@denx.de.
	4	+ *
	5	+ * See file CREDITS for list of people who contributed to this
	6	+ * project.
	7	+ *
	8	+ * This program is free software; you can redistribute it and/or
	9	+ * modify it under the terms of the GNU General Public License as
	10	+ * published by the Free Software Foundation; either version 2 of
	11	+ * the License, or (at your option) any later version.
	12	+ *
	13	+ * This program is distributed in the hope that it will be useful,
	14	+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	16	+ * GNU General Public License for more details.
	17	+ *
	18	+ * You should have received a copy of the GNU General Public License
	19	+ * along with this program; if not, write to the Free Software
	20	+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
	21	+ * MA 02111-1307 USA
	22	+ *
	23	+ */
	24	+
	25	+#define TWS_IMPLEMENTATION
	26	+#include <common.h>
	27	+
	28	+/=====================================================================/
	29	+/* Public Functions */
	30	+/=====================================================================/
	31	+
	32	+/*-----------------------------------------------------------------------
	33	+ * Read bits
	34	+ */
	35	+int tws_read(uchar *buffer, int len)
	36	+{
	37	+ int rem = len;
	38	+ uchar accu, shift;
	39	+
	40	+ debug("tws_read: buffer %p len %d\n", buffer, len);
	41	+
	42	+ /* Configure the data pin for input */
	43	+ tws_data_config_output(0);
	44	+
	45	+ /* Disable WR, i.e. setup a read */
	46	+ tws_wr(0);
	47	+ udelay(1);
	48	+
	49	+ /* Rise CE */
	50	+ tws_ce(1);
	51	+ udelay(1);
	52	+
	53	+ for (; rem > 0; ) {
	54	+ for (shift = 0, accu = 0;
	55	+ (rem > 0) && (shift < 8);
	56	+ rem--, shift++) {
	57	+ tws_clk(1);
	58	+ udelay(10);
	59	+ accu \|= (tws_data_read() << shift); /* LSB first */
	60	+ tws_clk(0);
	61	+ udelay(10);
	62	+ }
	63	+ *buffer++ = accu;
	64	+ }
	65	+
	66	+ /* Lower CE */
	67	+ tws_ce(0);
	68	+
	69	+ return len - rem;
	70	+}
	71	+
	72	+
	73	+/*-----------------------------------------------------------------------
	74	+ * Write bits
	75	+ */
	76	+int tws_write(uchar *buffer, int len)
	77	+{
	78	+ int rem = len;
	79	+ uchar accu, shift;
	80	+
	81	+ debug("tws_write: buffer %p len %d\n", buffer, len);
	82	+
	83	+ /* Configure the data pin for output */
	84	+ tws_data_config_output(1);
	85	+
	86	+ /* Enable WR, i.e. setup a write */
	87	+ tws_wr(1);
	88	+ udelay(1);
	89	+
	90	+ /* Rise CE */
	91	+ tws_ce(1);
	92	+ udelay(1);
	93	+
	94	+ for (; rem > 0; ) {
	95	+ for (shift = 0, accu = *buffer++;
	96	+ (rem > 0) && (shift < 8);
	97	+ rem--, shift++) {
	98	+ tws_data(accu & 0x01); /* LSB first */
	99	+ tws_clk(1);
	100	+ udelay(10);
	101	+ tws_clk(0);
	102	+ udelay(10);
	103	+ accu >>= 1;
	104	+ }
	105	+ }
	106	+
	107	+ /* Lower CE */
	108	+ tws_ce(0);
	109	+
	110	+ return len - rem;
	111	+}