diff options
author | Maciej Purski <m.purski@samsung.com> | 2018-04-23 16:33:40 +0200 |
---|---|---|
committer | Mark Brown <broonie@kernel.org> | 2018-05-17 16:05:49 +0900 |
commit | d3d64537c33956c94cfa2376b87d8917868a0f5e (patch) | |
tree | a3f1856e09922e4afc9467d091df7d4096d2ea76 /drivers/regulator/core.c | |
parent | a085a31af566254fb8f7721911c828c8fa797894 (diff) | |
download | linux-d3d64537c33956c94cfa2376b87d8917868a0f5e.tar.bz2 |
regulator: core: Resolve coupled regulators
On Odroid XU3/4 and other Exynos5422 based boards there is a case, that
different devices on the board are supplied by different regulators
with non-fixed voltages. If one of these devices temporarily requires
higher voltage, there might occur a situation that the spread between
two devices' voltages is so high, that there is a risk of changing
'high' and 'low' states on the interconnection between devices powered
by those regulators.
Fill coupling descriptor with data obtained from DTS using previously
defined of_functions. Fail to register a regulator, if some data
inconsistency occurs. If some coupled regulators are not yet registered,
don't fail to register, but try to resolve them in late init call.
Signed-off-by: Maciej Purski <m.purski@samsung.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/regulator/core.c')
-rw-r--r-- | drivers/regulator/core.c | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index 0ca941b53571..6ed568b96c0e 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -4129,6 +4129,96 @@ static int regulator_register_resolve_supply(struct device *dev, void *data) return 0; } +static int regulator_fill_coupling_array(struct regulator_dev *rdev) +{ + struct coupling_desc *c_desc = &rdev->coupling_desc; + int n_coupled = c_desc->n_coupled; + struct regulator_dev *c_rdev; + int i; + + for (i = 1; i < n_coupled; i++) { + /* already resolved */ + if (c_desc->coupled_rdevs[i]) + continue; + + c_rdev = of_parse_coupled_regulator(rdev, i - 1); + + if (c_rdev) { + c_desc->coupled_rdevs[i] = c_rdev; + c_desc->n_resolved++; + } + } + + if (rdev->coupling_desc.n_resolved < n_coupled) + return -1; + else + return 0; +} + +static int regulator_register_fill_coupling_array(struct device *dev, + void *data) +{ + struct regulator_dev *rdev = dev_to_rdev(dev); + + if (!IS_ENABLED(CONFIG_OF)) + return 0; + + if (regulator_fill_coupling_array(rdev)) + rdev_dbg(rdev, "unable to resolve coupling\n"); + + return 0; +} + +static int regulator_resolve_coupling(struct regulator_dev *rdev) +{ + int n_phandles; + + if (!IS_ENABLED(CONFIG_OF)) + n_phandles = 0; + else + n_phandles = of_get_n_coupled(rdev); + + if (n_phandles + 1 > MAX_COUPLED) { + rdev_err(rdev, "too many regulators coupled\n"); + return -EPERM; + } + + /* + * Every regulator should always have coupling descriptor filled with + * at least pointer to itself. + */ + rdev->coupling_desc.coupled_rdevs[0] = rdev; + rdev->coupling_desc.n_coupled = n_phandles + 1; + rdev->coupling_desc.n_resolved++; + + /* regulator isn't coupled */ + if (n_phandles == 0) + return 0; + + /* regulator, which can't change its voltage, can't be coupled */ + if (!regulator_ops_is_valid(rdev, REGULATOR_CHANGE_VOLTAGE)) { + rdev_err(rdev, "voltage operation not allowed\n"); + return -EPERM; + } + + if (rdev->constraints->max_spread <= 0) { + rdev_err(rdev, "wrong max_spread value\n"); + return -EPERM; + } + + if (!of_check_coupling_data(rdev)) + return -EPERM; + + /* + * After everything has been checked, try to fill rdevs array + * with pointers to regulators parsed from device tree. If some + * regulators are not registered yet, retry in late init call + */ + regulator_fill_coupling_array(rdev); + + return 0; +} + /** * regulator_register - register regulator * @regulator_desc: regulator to register @@ -4262,6 +4352,13 @@ regulator_register(const struct regulator_desc *regulator_desc, if (ret < 0) goto wash; + mutex_lock(®ulator_list_mutex); + ret = regulator_resolve_coupling(rdev); + mutex_unlock(®ulator_list_mutex); + + if (ret != 0) + goto wash; + /* add consumers devices */ if (init_data) { mutex_lock(®ulator_list_mutex); @@ -4756,6 +4853,9 @@ static int __init regulator_init_complete(void) class_for_each_device(®ulator_class, NULL, NULL, regulator_late_cleanup); + class_for_each_device(®ulator_class, NULL, NULL, + regulator_register_fill_coupling_array); + return 0; } late_initcall_sync(regulator_init_complete); |