[U-Boot] [PATCH v4 2/2] hwmon: do not init sensors on startup

Heiko Schocher
2011-08-01T11:08:18Z

The U-Boot Design Principles[1] clearly say:

Initialize devices only when they are needed within U-Boot, i.e. don't
initialize the Ethernet interface(s) unless U-Boot performs a download
over Ethernet; don't initialize any IDE or USB devices unless U-Boot
actually tries to load files from these, etc. (and don't forget to
shut down these devices after using them - otherwise nasty things may
happen when you try to boot your OS).

So, do not initialize and read the sensors on startup.

Signed-off-by: Heiko Schocher <hs@denx.de>
cc: Wolfgang Denk <wd@denx.de>
cc: Holger Brunck <holger.brunck@keymile.com>

---
- changes since v1
add comments from Wolfgang Denk
use BUILD_BUG_ON to create a compileerror if there are
defined more than 32 sensors.

- changes since v2
don;t include genutils.h, as macro is now in common.h

- changes since v3
do not initialize static sensor_initialized with 0

arch/powerpc/lib/board.c | 3 ---
common/cmd_dtt.c | 16 ++++++++++++++--
drivers/hwmon/adm1021.c | 27 +++------------------------
drivers/hwmon/adt7460.c | 2 +-
drivers/hwmon/ds1621.c | 19 +------------------
drivers/hwmon/ds1775.c | 19 +------------------
drivers/hwmon/lm63.c | 19 +------------------
drivers/hwmon/lm73.c | 20 ++------------------
drivers/hwmon/lm75.c | 29 ++---------------------------
drivers/hwmon/lm81.c | 21 ++-------------------
include/dtt.h | 2 +-
11 files changed, 28 insertions(+), 149 deletions(-)

diff --git a/arch/powerpc/lib/board.c b/arch/powerpc/lib/board.c
index aaa5add..e84cd52 100644
--- a/arch/powerpc/lib/board.c
+++ b/arch/powerpc/lib/board.c
@@ -946,9 +946,6 @@ void board_init_r (gd_t *id, ulong dest_addr)

WATCHDOG_RESET ();

-#if defined(CONFIG_DTT) /* Digital Thermometers and Thermostats */
- dtt_init ();
-#endif
#if defined(CONFIG_CMD_SCSI)
WATCHDOG_RESET ();
puts ("SCSI: ");
diff --git a/common/cmd_dtt.c b/common/cmd_dtt.c
index 3388e43..31aa420 100644
--- a/common/cmd_dtt.c
+++ b/common/cmd_dtt.c
@@ -28,12 +28,16 @@
#include <dtt.h>
#include <i2c.h>

+static unsigned long sensor_initialized = 0xffffffff;
+
int do_dtt (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
int i;
unsigned char sensors[] = CONFIG_DTT_SENSORS;
int old_bus;

+ /* Force a compilation error, if there are more then 32 sensors */
+ BUILD_BUG_ON(sizeof(sensors) > 32);
/* switch to correct I2C bus */
old_bus = I2C_GET_BUS();
I2C_SET_BUS(CONFIG_SYS_DTT_BUS_NUM);
@@ -42,8 +46,16 @@ int do_dtt (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
* Loop through sensors, read
* temperature, and output it.
*/
- for (i = 0; i < sizeof (sensors); i++)
- printf ("DTT%d: %i C\n", i + 1, dtt_get_temp (sensors[i]));
+ for (i = 0; i < sizeof(sensors); i++) {
+ if ((sensor_initialized & (1 << i)) != 0) {
+ if (dtt_init_one(sensors[i]) != 0) {
+ printf("DTT%d: Failed init!\n", i);
+ continue;
+ }
+ sensor_initialized &= ~(1 << i);
+ }
+ printf("DTT%d: %i C\n", i + 1, dtt_get_temp(sensors[i]));
+ }

/* switch back to original I2C bus */
I2C_SET_BUS(old_bus);
diff --git a/drivers/hwmon/adm1021.c b/drivers/hwmon/adm1021.c
index d753e9a..d074cb7 100644
--- a/drivers/hwmon/adm1021.c
+++ b/drivers/hwmon/adm1021.c
@@ -109,8 +109,8 @@ dtt_write (int sensor, int reg, int val)
return 0;
} /* dtt_write() */

-static int
-_dtt_init (int sensor)
+int
+dtt_init_one(int sensor)
{
dtt_cfg_t *dcp = &dttcfg[sensor >> 1];
int reg, val;
@@ -164,28 +164,7 @@ _dtt_init (int sensor)
return 1;

return 0;
-} /* _dtt_init() */
-
-int
-dtt_init (void)
-{
- int i;
- unsigned char sensors[] = CONFIG_DTT_SENSORS;
- const char *const header = "DTT: ";
-
- /* switch to correct I2C bus */
- I2C_SET_BUS(CONFIG_SYS_DTT_BUS_NUM);
-
- for (i = 0; i < sizeof(sensors); i++) {
- if (_dtt_init(sensors[i]) != 0)
- printf ("%s%d FAILED INIT\n", header, i+1);
- else
- printf ("%s%d is %i C\n", header, i+1,
- dtt_get_temp(sensors[i]));
- }
-
- return (0);
-} /* dtt_init() */
+} /* dtt_init_one() */

int
dtt_get_temp (int sensor)
diff --git a/drivers/hwmon/adt7460.c b/drivers/hwmon/adt7460.c
index caef70a..b7e36fe 100644
--- a/drivers/hwmon/adt7460.c
+++ b/drivers/hwmon/adt7460.c
@@ -50,7 +50,7 @@ int dtt_write(int sensor, int reg, int val)
return 0;
}

-int dtt_init(void)
+int dtt_init_one(int sensor)
{
printf("ADT7460@I2C address 0x%2x\n", ADT7460_ADDRESS);

diff --git a/drivers/hwmon/ds1621.c b/drivers/hwmon/ds1621.c
index 5a2ea62..4e1db6d 100644
--- a/drivers/hwmon/ds1621.c
+++ b/drivers/hwmon/ds1621.c
@@ -126,7 +126,7 @@ int dtt_write(int sensor, int reg, int val)
}

-static int _dtt_init(int sensor)
+int dtt_init_one(int sensor)
{
int val;

@@ -155,23 +155,6 @@ static int _dtt_init(int sensor)
return 0;
}

-
-int dtt_init (void)
-{
- int i;
- unsigned char sensors[] = CONFIG_DTT_SENSORS;
-
- for (i = 0; i < sizeof(sensors); i++) {
- if (_dtt_init(sensors[i]) != 0)
- printf("DTT%d: FAILED\n", i + 1);
- else
- printf("DTT%d: %i C\n", i + 1, dtt_get_temp(sensors[i]));
- }
-
- return (0);
-}
-
-
int dtt_get_temp(int sensor)
{
int i;
diff --git a/drivers/hwmon/ds1775.c b/drivers/hwmon/ds1775.c
index 80fb26f..feabdf2 100644
--- a/drivers/hwmon/ds1775.c
+++ b/drivers/hwmon/ds1775.c
@@ -98,7 +98,7 @@ int dtt_write(int sensor, int reg, int val)
}

-static int _dtt_init(int sensor)
+int dtt_init_one(int sensor)
{
int val;

@@ -133,23 +133,6 @@ static int _dtt_init(int sensor)
return 0;
}

-
-int dtt_init (void)
-{
- int i;
- unsigned char sensors[] = CONFIG_DTT_SENSORS;
-
- for (i = 0; i < sizeof(sensors); i++) {
- if (_dtt_init(sensors[i]) != 0)
- printf("DTT%d: FAILED\n", i+1);
- else
- printf("DTT%d: %i C\n", i+1, dtt_get_temp(sensors[i]));
- }
-
- return (0);
-}
-
-
int dtt_get_temp(int sensor)
{
return (dtt_read(sensor, DTT_READ_TEMP) / 256);
diff --git a/drivers/hwmon/lm63.c b/drivers/hwmon/lm63.c
index 2f1f3cf..f3adf64 100644
--- a/drivers/hwmon/lm63.c
+++ b/drivers/hwmon/lm63.c
@@ -101,7 +101,7 @@ static int is_lm64(int sensor)
return sensor && (sensor != DTT_I2C_LM63_ADDR);
}

-static int _dtt_init(int sensor)
+int dtt_init_one(int sensor)
{
int i;
int val;
@@ -175,20 +175,3 @@ int dtt_get_temp(int sensor)
/* Ignore LSB for now, U-Boot only prints natural numbers */
return temp >> 8;
}
-
-int dtt_init(void)
-{
- int i;
- unsigned char sensors[] = CONFIG_DTT_SENSORS;
- const char *const header = "DTT: ";
-
- for (i = 0; i < sizeof(sensors); i++) {
- if (_dtt_init(sensors[i]) != 0)
- printf("%s%d FAILED INIT\n", header, i + 1);
- else
- printf("%s%d is %i C\n", header, i + 1,
- dtt_get_temp(sensors[i]));
- }
-
- return 0;
-}
diff --git a/drivers/hwmon/lm73.c b/drivers/hwmon/lm73.c
index 7b5d893..45cc6db 100644
--- a/drivers/hwmon/lm73.c
+++ b/drivers/hwmon/lm73.c
@@ -112,7 +112,7 @@ int dtt_write(int const sensor, int const reg, int const val)
dlen);
} /* dtt_write() */

-static int _dtt_init(int const sensor)
+int dtt_init_one(int const sensor)
{
int val;

@@ -148,23 +148,7 @@ static int _dtt_init(int const sensor)

dtt_read(sensor, DTT_CONTROL); /* clear temperature flags */
return 0;
-} /* _dtt_init() */
-
-int dtt_init(void)
-{
- int i;
- unsigned char sensors[] = CONFIG_DTT_SENSORS;
- const char *const header = "DTT: ";
-
- for (i = 0; i < sizeof(sensors); i++) {
- if (0 != _dtt_init(sensors[i]))
- printf("%s%d FAILED INIT\n", header, i + 1);
- else
- printf("%s%d is %i C\n", header, i + 1,
- dtt_get_temp(sensors[i]));
- }
- return 0;
-} /* dtt_init() */
+} /* dtt_init_one() */

int dtt_get_temp(int const sensor)
{
diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c
index 8119821..29c1a39 100644
--- a/drivers/hwmon/lm75.c
+++ b/drivers/hwmon/lm75.c
@@ -119,7 +119,7 @@ int dtt_write(int sensor, int reg, int val)
} /* dtt_write() */

-static int _dtt_init(int sensor)
+int dtt_init_one(int sensor)
{
int val;

@@ -145,32 +145,7 @@ static int _dtt_init(int sensor)
return 1;

return 0;
-} /* _dtt_init() */
-
-
-int dtt_init (void)
-{
- int i;
- unsigned char sensors[] = CONFIG_DTT_SENSORS;
- const char *const header = "DTT: ";
- int old_bus;
-
- /* switch to correct I2C bus */
- old_bus = I2C_GET_BUS();
- I2C_SET_BUS(CONFIG_SYS_DTT_BUS_NUM);
-
- for (i = 0; i < sizeof(sensors); i++) {
- if (_dtt_init(sensors[i]) != 0)
- printf("%s%d FAILED INIT\n", header, i+1);
- else
- printf("%s%d is %i C\n", header, i+1,
- dtt_get_temp(sensors[i]));
- }
- /* switch back to original I2C bus */
- I2C_SET_BUS(old_bus);
-
- return (0);
-} /* dtt_init() */
+} /* dtt_init_one() */

int dtt_get_temp(int sensor)
{
diff --git a/drivers/hwmon/lm81.c b/drivers/hwmon/lm81.c
index afe5b0d..f1572ba 100644
--- a/drivers/hwmon/lm81.c
+++ b/drivers/hwmon/lm81.c
@@ -89,7 +89,7 @@ int dtt_write(int sensor, int reg, int val)
#define DTT_CONFIG 0x40
#define DTT_ADR 0x48

-static int _dtt_init(int sensor)
+int dtt_init_one(int sensor)
{
int man;
int adr;
@@ -111,26 +111,9 @@ static int _dtt_init(int sensor)

debug ("DTT: Found LM81@%x Rev: %d\n", adr, rev);
return 0;
-} /* _dtt_init() */
+} /* dtt_init_one() */

-int dtt_init (void)
-{
- int i;
- unsigned char sensors[] = CONFIG_DTT_SENSORS;
- const char *const header = "DTT: ";
-
- for (i = 0; i < sizeof(sensors); i++) {
- if (_dtt_init(sensors[i]) != 0)
- printf("%s%d FAILED INIT\n", header, i+1);
- else
- printf("%s%d is %i C\n", header, i+1,
- dtt_get_temp(sensors[i]));
- }
-
- return (0);
-} /* dtt_init() */
-
#define TEMP_FROM_REG(temp) \
((temp)<256?((((temp)&0x1fe) >> 1) * 10) + ((temp) & 1) * 5: \
((((temp)&0x1fe) >> 1) -255) * 10 - ((temp) & 1) * 5) \
diff --git a/include/dtt.h b/include/dtt.h
index 399b64a..9e6c08c 100644
--- a/include/dtt.h
+++ b/include/dtt.h
@@ -52,7 +52,7 @@
#endif
#endif /* CONFIG_DTT_ADM1021 */

-extern int dtt_init (void);
+extern int dtt_init_one(int);
extern int dtt_read(int sensor, int reg);
extern int dtt_write(int sensor, int reg, int val);
extern int dtt_get_temp(int sensor);
--
1.7.6