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regulator: Disable unused regulator

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bootloaders such as u-boot might enable regulators, or simply regulators could
be enabled by default by the PMIC, even if we don't have a driver for
the device or subsystem.
Disable unused regulators just before going to userland.
A tunable hw.regulator.disable_unused is added to not disable them in case
this causes problems on some board but the default behavior is to disable
everything unused.
I prefer to break thinks now and fix them rather than never switch to the
case were we disable regulators.

Tested on : Pine64-LTS (an idle board goes from ~0.33A to ~0.27A)
Tested on : BananaPi M2
Differential Revision:	https://reviews.freebsd.org/D14781
This commit is contained in:
Emmanuel Vadot 2018-04-04 06:44:24 +00:00
parent 9f6fffc731
commit 3f01401236
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=331989
1 changed files with 31 additions and 0 deletions
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31
sys/dev/extres/regulator/regulator.c
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@ -71,6 +71,7 @@ static int regnode_method_status(struct regnode *regnode, int *status);
static int regnode_method_set_voltage(struct regnode *regnode, int min_uvolt,
int max_uvolt, int *udelay);
static int regnode_method_get_voltage(struct regnode *regnode, int *uvolt);
static void regulator_shutdown(void *dummy);
/*
* Regulator controller methods.
@ -151,6 +152,36 @@ SX_SYSINIT(regulator_topology, &regnode_topo_lock, "Regulator topology lock");
#define REGNODE_XLOCK(_sc) sx_xlock(&((_sc)->lock))
#define REGNODE_UNLOCK(_sc) sx_unlock(&((_sc)->lock))
SYSINIT(regulator_shutdown, SI_SUB_LAST, SI_ORDER_ANY, regulator_shutdown,
NULL);
/*
* Disable unused regulator
* We run this function at SI_SUB_LAST which mean that every driver that needs
* regulator should have already enable them.
* All the remaining regulators should be those left enabled by the bootloader
* or enable by default by the PMIC.
*/
static void
regulator_shutdown(void *dummy)
{
struct regnode *entry;
int disable = 1;
REG_TOPO_SLOCK();
TUNABLE_INT_FETCH("hw.regulator.disable_unused", &disable);
TAILQ_FOREACH(entry, &regnode_list, reglist_link) {
if (entry->enable_cnt == 0 &&
entry->std_param.always_on == 0 && disable) {
if (bootverbose)
printf("regulator: shuting down %s\n",
entry->name);
regnode_stop(entry, 0);
}
}
REG_TOPO_UNLOCK();
}
/*
* sysctl handler
*/