FreeCalypso > hg > freecalypso-tools
view target-utils/libbase/abbdrv.c @ 465:003e48f8ebe1
rvinterf/etmsync/fsnew.c: cast 0 to (char *) for execl sentinel
I generally don't use NULL and use plain 0 instead, based on a "NULL
considered harmful" discussion on the classiccmp mailing list many aeons
ago (I couldn't find it, and I reason that it must have been 2005 or
earlier), but a recent complaint by a packager sent me searching, and I
found this:
https://ewontfix.com/11/
While I don't give a @#$% about "modern" systems and code-nazi tools,
I realized that passing a plain 0 as a pointer sentinel in execl is wrong
because it will break on systems where pointers are longer than the plain
int type. Again, I don't give a @#$% about the abomination of x86_64 and
the like, but if anyone ever manages to port my code to something like a
PDP-11 (16-bit int, 32-bit long and pointers), then passing a plain 0
as a function argument where a pointer is expected most definitely won't
work: if the most natural stack slot and SP alignment unit is 16 bits,
fitting an int, with longs and pointers taking up two such slots, then
the call stack will be totally wrong with a plain 0 passed for a pointer.
Casting the 0 to (char *) ought to be the most kosher solution for the
most retro systems possible.
| author | Mychaela Falconia <falcon@freecalypso.org> |
|---|---|
| date | Mon, 11 Feb 2019 00:00:19 +0000 |
| parents | e7502631a0f9 |
| children | 3d73d4d3527f |
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/* Driver for Analog Baseband Circuit (TWL3025) */ /* lifted from OsmocomBB and ported to FreeCalypso target-utils environment */ /* (C) 2010 by Harald Welte <laforge@gnumonks.org> * * All Rights Reserved * * 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., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. * */ #include "types.h" #include "abbdefs.h" /* TWL3025 */ #define REG_PAGE(n) ((n) >> 7) #define REG_ADDR(n) ((n) & 0x1f) #define TWL3025_DEV_IDX 0 /* On the SPI bus */ #define TWL3025_TSP_DEV_IDX 0 /* On the TSP bus */ int abb_state_initdone, abb_state_page; void abb_reg_write(reg, data) { u16 tx; if (reg != PAGEREG && REG_PAGE(reg) != abb_state_page) abb_select_page(REG_PAGE(reg)); tx = ((data & 0x3ff) << 6) | (REG_ADDR(reg) << 1); spi_xfer(TWL3025_DEV_IDX, 16, &tx, 0); } u16 abb_reg_read(reg) { u16 tx, rx; if (REG_PAGE(reg) != abb_state_page) abb_select_page(REG_PAGE(reg)); tx = (REG_ADDR(reg) << 1) | 1; /* A read cycle contains two SPI transfers */ spi_xfer(TWL3025_DEV_IDX, 16, &tx, &rx); osmo_delay_ms(1); spi_xfer(TWL3025_DEV_IDX, 16, &tx, &rx); rx >>= 6; return rx; } /* Switch the register page of the TWL3025 */ abb_select_page(page) { if (page == 0) abb_reg_write(PAGEREG, 1 << 0); else abb_reg_write(PAGEREG, 1 << 1); abb_state_page = page; return(0); } abb_init() { if (abb_state_initdone) return(0); spi_init(); abb_select_page(0); /* CLK13M enable */ abb_reg_write(TOGBR2, TOGBR2_ACTS); osmo_delay_ms(1); /* for whatever reason we need to do this twice */ abb_reg_write(TOGBR2, TOGBR2_ACTS); osmo_delay_ms(1); abb_state_initdone = 1; return(1); } void abb_power_off() { abb_init(); serial_flush(); abb_reg_write(VRPCDEV, 0x01); }