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author | fishsoupisgood <github@madingley.org> | 2019-04-29 01:17:54 +0100 |
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committer | fishsoupisgood <github@madingley.org> | 2019-05-27 03:43:43 +0100 |
commit | 3f2546b2ef55b661fd8dd69682b38992225e86f6 (patch) | |
tree | 65ca85f13617aee1dce474596800950f266a456c /roms/u-boot/drivers/twserial/soft_tws.c | |
download | qemu-master.tar.gz qemu-master.tar.bz2 qemu-master.zip |
Diffstat (limited to 'roms/u-boot/drivers/twserial/soft_tws.c')
-rw-r--r-- | roms/u-boot/drivers/twserial/soft_tws.c | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/roms/u-boot/drivers/twserial/soft_tws.c b/roms/u-boot/drivers/twserial/soft_tws.c new file mode 100644 index 00000000..d0bf93d9 --- /dev/null +++ b/roms/u-boot/drivers/twserial/soft_tws.c @@ -0,0 +1,94 @@ +/* + * (C) Copyright 2009 + * Detlev Zundel, DENX Software Engineering, dzu@denx.de. + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#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; +} |