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Handle (i.e. don't lock up the kernel in hd44780_busy_wait) the case of the

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LCD not being there.
This commit is contained in:
joff 2005-01-09 15:43:56 +00:00
parent 8d65a2e17f
commit 838c742991
2 changed files with 70 additions and 22 deletions
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84
sys/dev/ic/hd44780_subr.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: hd44780_subr.c,v 1.2 2005/01/08 20:17:22 joff Exp $ */
/* $NetBSD: hd44780_subr.c,v 1.3 2005/01/09 15:43:56 joff Exp $ */
/*
* Copyright (c) 2002 Dennis I. Chernoivanov
@ -32,7 +32,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: hd44780_subr.c,v 1.2 2005/01/08 20:17:22 joff Exp $");
__KERNEL_RCSID(0, "$NetBSD: hd44780_subr.c,v 1.3 2005/01/09 15:43:56 joff Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@ -48,8 +48,6 @@ __KERNEL_RCSID(0, "$NetBSD: hd44780_subr.c,v 1.2 2005/01/08 20:17:22 joff Exp $"
#include <dev/ic/hd44780reg.h>
#include <dev/ic/hd44780_subr.h>
static void hd44780_init(struct hd44780_chip *);
/*
* Finish device attach. sc_writereg, sc_readreg and sc_flags must be properly
* initialized prior to this call.
@ -58,6 +56,7 @@ void
hd44780_attach_subr(sc)
struct hd44780_chip *sc;
{
int err = 0;
/* Putc/getc are supposed to be set by platform-dependent code. */
if ((sc->sc_writereg == NULL) || (sc->sc_readreg == NULL))
sc->sc_dev_ok = 0;
@ -69,24 +68,25 @@ hd44780_attach_subr(sc)
sc->sc_dev_ok = 0;
if (sc->sc_dev_ok) {
if ((sc->sc_flags & HD_UP) == 0)
hd44780_init(sc);
if ((sc->sc_flags & HD_UP) == 0)
err = hd44780_init(sc);
if (err != 0)
printf("%s: not responding or unconnected\n", sc->sc_dev->dv_xname);
/* Turn display on and clear it. */
hd44780_ir_write(sc, cmd_dispctl(1, 0, 0));
hd44780_ir_write(sc, cmd_clear());
}
}
/*
* Initialize 4-bit or 8-bit connected device.
*/
static void
int
hd44780_init(sc)
struct hd44780_chip *sc;
{
u_int8_t cmd;
u_int8_t cmd, dat;
sc->sc_flags &= ~(HD_TIMEDOUT|HD_UP);
sc->sc_dev_ok = 1;
cmd = cmd_init(sc->sc_flags & HD_8BIT);
hd44780_ir_write(sc, cmd);
delay(HD_TIMEOUT_LONG);
@ -107,6 +107,28 @@ hd44780_init(sc)
hd44780_ir_write(sc, cmd_dispctl(0, 0, 0));
hd44780_ir_write(sc, cmd_clear());
hd44780_ir_write(sc, cmd_modset(1, 0));
if (sc->sc_flags & HD_TIMEDOUT) {
sc->sc_flags &= ~HD_UP;
return EIO;
}
/* Turn display on and clear it. */
hd44780_ir_write(sc, cmd_clear());
hd44780_ir_write(sc, cmd_dispctl(1, 0, 0));
/* Attempt a simple probe for presence */
hd44780_ir_write(sc, cmd_ddramset(0x5));
hd44780_ir_write(sc, cmd_shift(0, 1));
hd44780_busy_wait(sc);
if ((dat = hd44780_ir_read(sc) & 0x7f) != 0x6) {
sc->sc_dev_ok = 0;
sc->sc_flags &= ~HD_UP;
return EIO;
}
hd44780_ir_write(sc, cmd_ddramset(0));
return 0;
}
/*
@ -163,13 +185,7 @@ hd44780_ioctl_subr(sc, cmd, data)
/* Reset the LCD. */
case HLCD_RESET:
hd44780_ir_write(sc, cmd_init(sc->sc_flags & HD_8BIT));
hd44780_ir_write(sc, cmd_init(sc->sc_flags & HD_8BIT));
hd44780_ir_write(sc, cmd_init(sc->sc_flags & HD_8BIT));
hd44780_ir_write(sc, cmd_init(sc->sc_flags & HD_8BIT));
hd44780_ir_write(sc, cmd_modset(1, 0));
hd44780_ir_write(sc, cmd_dispctl(1, 0, 0));
hd44780_ir_write(sc, cmd_clear());
error = hd44780_init(sc);
break;
/* Get the current cursor position. */
@ -238,6 +254,9 @@ hd44780_ioctl_subr(sc, cmd, data)
error = EINVAL;
}
if (sc->sc_flags & HD_TIMEDOUT)
error = EIO;
return error;
}
@ -308,6 +327,23 @@ hd44780_ddram_redraw(sc, io)
hd44780_dr_write(sc, io->buf[i]);
}
void
hd44780_busy_wait(sc)
struct hd44780_chip *sc;
{
int nloops = 100;
if (sc->sc_flags & HD_TIMEDOUT)
return;
while(nloops-- && (hd44780_ir_read(sc) & BUSY_FLAG) == BUSY_FLAG);
if (nloops == 0) {
sc->sc_flags |= HD_TIMEDOUT;
sc->sc_dev_ok = 0;
}
}
#if defined(HD44780_STD_WIDE)
/*
* Standard 8-bit version of 'sc_writereg' (8-bit port, 8-bit access)
@ -321,6 +357,9 @@ hd44780_writereg(sc, reg, cmd)
bus_space_tag_t iot = sc->sc_iot;
bus_space_handle_t ioh;
if (sc->sc_dev_ok == 0)
return;
if (reg == 0)
ioh = sc->sc_ioir;
else
@ -341,6 +380,9 @@ hd44780_readreg(sc, reg)
bus_space_tag_t iot = sc->sc_iot;
bus_space_handle_t ioh;
if (sc->sc_dev_ok == 0)
return;
if (reg == 0)
ioh = sc->sc_ioir;
else
@ -362,6 +404,9 @@ hd44780_writereg(sc, reg, cmd)
bus_space_tag_t iot = sc->sc_iot;
bus_space_handle_t ioh;
if (sc->sc_dev_ok == 0)
return;
if (reg == 0)
ioh = sc->sc_ioir;
else
@ -385,6 +430,9 @@ hd44780_readreg(sc, reg)
bus_space_handle_t ioh;
u_int8_t rd, dat;
if (sc->sc_dev_ok == 0)
return;
if (reg == 0)
ioh = sc->sc_ioir;
else

8
sys/dev/ic/hd44780_subr.h
View File

@ -1,4 +1,4 @@
/* $NetBSD: hd44780_subr.h,v 1.2 2005/01/08 20:17:22 joff Exp $ */
/* $NetBSD: hd44780_subr.h,v 1.3 2005/01/09 15:43:56 joff Exp $ */
/*
* Copyright (c) 2002 Dennis I. Chernoivanov
@ -81,6 +81,7 @@ struct hd44780_chip {
#define HD_BIGFONT 0x04 /* 5x10 if set, 5x8 otherwise */
#define HD_KEYPAD 0x08 /* if set, keypad is connected */
#define HD_UP 0x10 /* if set, lcd has been initialized */
#define HD_TIMEDOUT 0x20 /* lcd has recently stopped talking */
u_char sc_flags;
u_char sc_rows; /* visible rows */
@ -99,9 +100,6 @@ struct hd44780_chip {
u_int8_t (* sc_readreg)(struct hd44780_chip *, u_int32_t);
};
#define hd44780_busy_wait(sc) \
while((hd44780_ir_read(sc) & BUSY_FLAG) == BUSY_FLAG)
#define hd44780_ir_write(sc, dat) \
do { \
hd44780_busy_wait(sc); \
@ -118,6 +116,8 @@ struct hd44780_chip {
(sc)->sc_readreg((sc), 1)
void hd44780_attach_subr(struct hd44780_chip *);
void hd44780_busy_wait(struct hd44780_chip *);
int hd44780_init(struct hd44780_chip *);
int hd44780_ioctl_subr(struct hd44780_chip *, u_long, caddr_t);
void hd44780_ddram_redraw(struct hd44780_chip *, struct hd44780_io *);