[RFC PATCH v1 1/6] regulator: core: Introduce API for machine-specific regulators coupling

Dmitry Osipenko
2019-04-14T18:06:00Z

Right now regulator core supports only one type of regulators coupling,
the "voltage max-spread" which keeps voltages of coupled regulators in a
given range. A more sophisticated coupling may be required in practice,
one example is the NVIDIA Tegra SoC's which besides the max-spreading
have other restrictions that must be adhered. Introduce API that allow
platforms to provide their own custom coupling algorithms.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
drivers/regulator/core.c | 18 ++++++++++++++++++
include/linux/regulator/machine.h | 19 +++++++++++++++++++
2 files changed, 37 insertions(+)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 186a37675b50..a98af47e0feb 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -59,6 +59,8 @@ static bool has_full_constraints;

static struct dentry *debugfs_root;

+static struct regulators_coupler *machine_regulators_coupler;
+
/*
* struct regulator_map
*
@@ -3596,6 +3598,12 @@ static int regulator_balance_voltage(struct regulator_dev *rdev,
return -EPERM;
}

+ if (n_coupled > 1 &&
+ machine_regulators_coupler &&
+ machine_regulators_coupler->balance_voltage)
+ return machine_regulators_coupler->balance_voltage(
+ machine_regulators_coupler, rdev, state);
+
for (i = 0; i < n_coupled; i++)
c_rdev_done[i] = false;

@@ -4706,6 +4714,16 @@ static int regulator_register_resolve_supply(struct device *dev, void *data)
return 0;
}

+int regulators_coupler_register(struct regulators_coupler *coupler)
+{
+ if (WARN_ON(machine_regulators_coupler))
+ return -EBUSY;
+
+ machine_regulators_coupler = coupler;
+
+ return 0;
+}
+
static void regulator_resolve_coupling(struct regulator_dev *rdev)
{
struct coupling_desc *c_desc = &rdev->coupling_desc;
diff --git a/include/linux/regulator/machine.h b/include/linux/regulator/machine.h
index 1d34a70ffda2..f15c8c5f7f6c 100644
--- a/include/linux/regulator/machine.h
+++ b/include/linux/regulator/machine.h
@@ -19,6 +19,7 @@
#include <linux/suspend.h>

struct regulator;
+struct regulator_dev;

/*
* Regulator operation constraint flags. These flags are used to enable
@@ -265,4 +266,22 @@ static inline int regulator_suspend_finish(void)
return 0;
}

+/**
+ * struct regulators_coupler - machine-specific regulators coupler
+ *
+ * A custom regulators coupler allows platform to customize coupling
+ * algorithm.
+ *
+ * @balance_voltage: Callback invoked when voltage of a coupled regulator is
+ * changing. The callee should perform voltage balancing
+ * and change voltage of the coupled regulators.
+ */
+struct regulators_coupler {
+ int (*balance_voltage)(struct regulators_coupler *coupler,
+ struct regulator_dev *rdev,
+ suspend_state_t state);
+};
+
+int regulators_coupler_register(struct regulators_coupler *coupler);
+
#endif
--
2.21.0