Commit d8ca7d18 authored by Dmitry Osipenko's avatar Dmitry Osipenko Committed by Mark Brown

regulator: core: Introduce API for regulators coupling customization

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 from each other. A more sophisticated coupling may be required
in practice, one example is the NVIDIA Tegra SoCs which besides the
max-spreading have other restrictions that must be adhered. Introduce API
that allow platforms to provide their own customized coupling algorithms.
Signed-off-by: default avatarDmitry Osipenko <digetx@gmail.com>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent a188339c
......@@ -28,6 +28,7 @@
#include <linux/regmap.h>
#include <linux/regulator/of_regulator.h>
#include <linux/regulator/consumer.h>
#include <linux/regulator/coupler.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/machine.h>
#include <linux/module.h>
......@@ -55,6 +56,7 @@ static DEFINE_MUTEX(regulator_list_mutex);
static LIST_HEAD(regulator_map_list);
static LIST_HEAD(regulator_ena_gpio_list);
static LIST_HEAD(regulator_supply_alias_list);
static LIST_HEAD(regulator_coupler_list);
static bool has_full_constraints;
static struct dentry *debugfs_root;
......@@ -3439,11 +3441,10 @@ static int regulator_get_optimal_voltage(struct regulator_dev *rdev,
struct coupling_desc *c_desc = &rdev->coupling_desc;
struct regulator_dev **c_rdevs = c_desc->coupled_rdevs;
struct regulation_constraints *constraints = rdev->constraints;
int max_spread = constraints->max_spread;
int desired_min_uV = 0, desired_max_uV = INT_MAX;
int max_current_uV = 0, min_current_uV = INT_MAX;
int highest_min_uV = 0, target_uV, possible_uV;
int i, ret;
int i, ret, max_spread;
bool done;
*current_uV = -1;
......@@ -3497,6 +3498,8 @@ static int regulator_get_optimal_voltage(struct regulator_dev *rdev,
}
}
max_spread = constraints->max_spread[0];
/*
* Let target_uV be equal to the desired one if possible.
* If not, set it to minimum voltage, allowed by other coupled
......@@ -3578,9 +3581,11 @@ static int regulator_balance_voltage(struct regulator_dev *rdev,
struct regulator_dev **c_rdevs;
struct regulator_dev *best_rdev;
struct coupling_desc *c_desc = &rdev->coupling_desc;
struct regulator_coupler *coupler = c_desc->coupler;
int i, ret, n_coupled, best_min_uV, best_max_uV, best_c_rdev;
bool best_c_rdev_done, c_rdev_done[MAX_COUPLED];
unsigned int delta, best_delta;
unsigned long c_rdev_done = 0;
bool best_c_rdev_done;
c_rdevs = c_desc->coupled_rdevs;
n_coupled = c_desc->n_coupled;
......@@ -3597,8 +3602,9 @@ static int regulator_balance_voltage(struct regulator_dev *rdev,
return -EPERM;
}
for (i = 0; i < n_coupled; i++)
c_rdev_done[i] = false;
/* Invoke custom balancer for customized couplers */
if (coupler && coupler->balance_voltage)
return coupler->balance_voltage(coupler, rdev, state);
/*
* Find the best possible voltage change on each loop. Leave the loop
......@@ -3625,7 +3631,7 @@ static int regulator_balance_voltage(struct regulator_dev *rdev,
*/
int optimal_uV = 0, optimal_max_uV = 0, current_uV = 0;
if (c_rdev_done[i])
if (test_bit(i, &c_rdev_done))
continue;
ret = regulator_get_optimal_voltage(c_rdevs[i],
......@@ -3660,7 +3666,8 @@ static int regulator_balance_voltage(struct regulator_dev *rdev,
if (ret < 0)
goto out;
c_rdev_done[best_c_rdev] = best_c_rdev_done;
if (best_c_rdev_done)
set_bit(best_c_rdev, &c_rdev_done);
} while (n_coupled > 1);
......@@ -4712,8 +4719,60 @@ static int regulator_register_resolve_supply(struct device *dev, void *data)
return 0;
}
int regulator_coupler_register(struct regulator_coupler *coupler)
{
mutex_lock(&regulator_list_mutex);
list_add_tail(&coupler->list, &regulator_coupler_list);
mutex_unlock(&regulator_list_mutex);
return 0;
}
static struct regulator_coupler *
regulator_find_coupler(struct regulator_dev *rdev)
{
struct regulator_coupler *coupler;
int err;
/*
* Note that regulators are appended to the list and the generic
* coupler is registered first, hence it will be attached at last
* if nobody cared.
*/
list_for_each_entry_reverse(coupler, &regulator_coupler_list, list) {
err = coupler->attach_regulator(coupler, rdev);
if (!err) {
if (!coupler->balance_voltage &&
rdev->coupling_desc.n_coupled > 2)
goto err_unsupported;
return coupler;
}
if (err < 0)
return ERR_PTR(err);
if (err == 1)
continue;
break;
}
return ERR_PTR(-EINVAL);
err_unsupported:
if (coupler->detach_regulator)
coupler->detach_regulator(coupler, rdev);
rdev_err(rdev,
"Voltage balancing for multiple regulator couples is unimplemented\n");
return ERR_PTR(-EPERM);
}
static void regulator_resolve_coupling(struct regulator_dev *rdev)
{
struct regulator_coupler *coupler = rdev->coupling_desc.coupler;
struct coupling_desc *c_desc = &rdev->coupling_desc;
int n_coupled = c_desc->n_coupled;
struct regulator_dev *c_rdev;
......@@ -4729,6 +4788,12 @@ static void regulator_resolve_coupling(struct regulator_dev *rdev)
if (!c_rdev)
continue;
if (c_rdev->coupling_desc.coupler != coupler) {
rdev_err(rdev, "coupler mismatch with %s\n",
rdev_get_name(c_rdev));
return;
}
regulator_lock(c_rdev);
c_desc->coupled_rdevs[i] = c_rdev;
......@@ -4742,10 +4807,12 @@ static void regulator_resolve_coupling(struct regulator_dev *rdev)
static void regulator_remove_coupling(struct regulator_dev *rdev)
{
struct regulator_coupler *coupler = rdev->coupling_desc.coupler;
struct coupling_desc *__c_desc, *c_desc = &rdev->coupling_desc;
struct regulator_dev *__c_rdev, *c_rdev;
unsigned int __n_coupled, n_coupled;
int i, k;
int err;
n_coupled = c_desc->n_coupled;
......@@ -4775,21 +4842,33 @@ static void regulator_remove_coupling(struct regulator_dev *rdev)
c_desc->coupled_rdevs[i] = NULL;
c_desc->n_resolved--;
}
if (coupler && coupler->detach_regulator) {
err = coupler->detach_regulator(coupler, rdev);
if (err)
rdev_err(rdev, "failed to detach from coupler: %d\n",
err);
}
kfree(rdev->coupling_desc.coupled_rdevs);
rdev->coupling_desc.coupled_rdevs = NULL;
}
static int regulator_init_coupling(struct regulator_dev *rdev)
{
int n_phandles;
int err, n_phandles;
size_t alloc_size;
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;
}
alloc_size = sizeof(*rdev) * (n_phandles + 1);
rdev->coupling_desc.coupled_rdevs = kzalloc(alloc_size, GFP_KERNEL);
if (!rdev->coupling_desc.coupled_rdevs)
return -ENOMEM;
/*
* Every regulator should always have coupling descriptor filled with
......@@ -4803,23 +4882,35 @@ static int regulator_init_coupling(struct regulator_dev *rdev)
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");
if (!of_check_coupling_data(rdev))
return -EPERM;
}
if (rdev->constraints->max_spread <= 0) {
rdev_err(rdev, "wrong max_spread value\n");
return -EPERM;
rdev->coupling_desc.coupler = regulator_find_coupler(rdev);
if (IS_ERR(rdev->coupling_desc.coupler)) {
err = PTR_ERR(rdev->coupling_desc.coupler);
rdev_err(rdev, "failed to get coupler: %d\n", err);
return err;
}
if (!of_check_coupling_data(rdev))
return 0;
}
static int generic_coupler_attach(struct regulator_coupler *coupler,
struct regulator_dev *rdev)
{
if (rdev->coupling_desc.n_coupled > 2) {
rdev_err(rdev,
"Voltage balancing for multiple regulator couples is unimplemented\n");
return -EPERM;
}
return 0;
}
static struct regulator_coupler generic_regulator_coupler = {
.attach_regulator = generic_coupler_attach,
};
/**
* regulator_register - register regulator
* @regulator_desc: regulator to register
......@@ -4981,7 +5072,9 @@ regulator_register(const struct regulator_desc *regulator_desc,
if (ret < 0)
goto wash;
mutex_lock(&regulator_list_mutex);
ret = regulator_init_coupling(rdev);
mutex_unlock(&regulator_list_mutex);
if (ret < 0)
goto wash;
......@@ -5030,6 +5123,7 @@ regulator_register(const struct regulator_desc *regulator_desc,
unset_supplies:
mutex_lock(&regulator_list_mutex);
unset_regulator_supplies(rdev);
regulator_remove_coupling(rdev);
mutex_unlock(&regulator_list_mutex);
wash:
kfree(rdev->constraints);
......@@ -5485,6 +5579,8 @@ static int __init regulator_init(void)
#endif
regulator_dummy_init();
regulator_coupler_register(&generic_regulator_coupler);
return ret;
}
......
......@@ -25,7 +25,8 @@ static const char *const regulator_states[PM_SUSPEND_MAX + 1] = {
[PM_SUSPEND_MAX] = "regulator-state-disk",
};
static void of_get_regulation_constraints(struct device_node *np,
static int of_get_regulation_constraints(struct device *dev,
struct device_node *np,
struct regulator_init_data **init_data,
const struct regulator_desc *desc)
{
......@@ -34,8 +35,13 @@ static void of_get_regulation_constraints(struct device_node *np,
struct device_node *suspend_np;
unsigned int mode;
int ret, i, len;
int n_phandles;
u32 pval;
n_phandles = of_count_phandle_with_args(np, "regulator-coupled-with",
NULL);
n_phandles = max(n_phandles, 0);
constraints->name = of_get_property(np, "regulator-name", NULL);
if (!of_property_read_u32(np, "regulator-min-microvolt", &pval))
......@@ -167,9 +173,17 @@ static void of_get_regulation_constraints(struct device_node *np,
if (!of_property_read_u32(np, "regulator-system-load", &pval))
constraints->system_load = pval;
if (!of_property_read_u32(np, "regulator-coupled-max-spread",
&pval))
constraints->max_spread = pval;
if (n_phandles) {
constraints->max_spread = devm_kzalloc(dev,
sizeof(*constraints->max_spread) * n_phandles,
GFP_KERNEL);
if (!constraints->max_spread)
return -ENOMEM;
of_property_read_u32_array(np, "regulator-coupled-max-spread",
constraints->max_spread, n_phandles);
}
if (!of_property_read_u32(np, "regulator-max-step-microvolt",
&pval))
......@@ -246,6 +260,8 @@ static void of_get_regulation_constraints(struct device_node *np,
suspend_state = NULL;
suspend_np = NULL;
}
return 0;
}
/**
......@@ -271,7 +287,9 @@ struct regulator_init_data *of_get_regulator_init_data(struct device *dev,
if (!init_data)
return NULL; /* Out of memory? */
of_get_regulation_constraints(node, &init_data, desc);
if (of_get_regulation_constraints(dev, node, &init_data, desc))
return NULL;
return init_data;
}
EXPORT_SYMBOL_GPL(of_get_regulator_init_data);
......@@ -477,7 +495,8 @@ int of_get_n_coupled(struct regulator_dev *rdev)
/* Looks for "to_find" device_node in src's "regulator-coupled-with" property */
static bool of_coupling_find_node(struct device_node *src,
struct device_node *to_find)
struct device_node *to_find,
int *index)
{
int n_phandles, i;
bool found = false;
......@@ -499,8 +518,10 @@ static bool of_coupling_find_node(struct device_node *src,
of_node_put(tmp);
if (found)
if (found) {
*index = i;
break;
}
}
return found;
......@@ -521,22 +542,23 @@ static bool of_coupling_find_node(struct device_node *src,
*/
bool of_check_coupling_data(struct regulator_dev *rdev)
{
int max_spread = rdev->constraints->max_spread;
struct device_node *node = rdev->dev.of_node;
int n_phandles = of_get_n_coupled(rdev);
struct device_node *c_node;
int index;
int i;
bool ret = true;
if (max_spread <= 0) {
dev_err(&rdev->dev, "max_spread value invalid\n");
return false;
}
/* iterate over rdev's phandles */
for (i = 0; i < n_phandles; i++) {
int max_spread = rdev->constraints->max_spread[i];
int c_max_spread, c_n_phandles;
if (max_spread <= 0) {
dev_err(&rdev->dev, "max_spread value invalid\n");
return false;
}
c_node = of_parse_phandle(node,
"regulator-coupled-with", i);
......@@ -553,22 +575,23 @@ bool of_check_coupling_data(struct regulator_dev *rdev)
goto clean;
}
if (of_property_read_u32(c_node, "regulator-coupled-max-spread",
&c_max_spread)) {
if (!of_coupling_find_node(c_node, node, &index)) {
dev_err(&rdev->dev, "missing 2-way linking for coupled regulators\n");
ret = false;
goto clean;
}
if (c_max_spread != max_spread) {
dev_err(&rdev->dev,
"coupled regulators max_spread mismatch\n");
if (of_property_read_u32_index(c_node, "regulator-coupled-max-spread",
index, &c_max_spread)) {
ret = false;
goto clean;
}
if (!of_coupling_find_node(c_node, node)) {
dev_err(&rdev->dev, "missing 2-way linking for coupled regulators\n");
if (c_max_spread != max_spread) {
dev_err(&rdev->dev,
"coupled regulators max_spread mismatch\n");
ret = false;
goto clean;
}
clean:
......
/* SPDX-License-Identifier: GPL-2.0 */
/*
* coupler.h -- SoC Regulator support, coupler API.
*
* Regulator Coupler Interface.
*/
#ifndef __LINUX_REGULATOR_COUPLER_H_
#define __LINUX_REGULATOR_COUPLER_H_
#include <linux/kernel.h>
#include <linux/suspend.h>
struct regulator_coupler;
struct regulator_dev;
/**
* struct regulator_coupler - customized regulator's coupler
*
* Regulator's coupler allows to customize coupling algorithm.
*
* @list: couplers list entry
* @attach_regulator: Callback invoked on creation of a coupled regulator,
* couples are unresolved at this point. The callee should
* check that it could handle the regulator and return 0 on
* success, -errno on failure and 1 if given regulator is
* not suitable for this coupler (case of having multiple
* regulators in a system). Callback shall be implemented.
* @detach_regulator: Callback invoked on destruction of a coupled regulator.
* This callback is optional and could be NULL.
* @balance_voltage: Callback invoked when voltage of a coupled regulator is
* changing. Called with all of the coupled rdev's being held
* under "consumer lock". The callee should perform voltage
* balancing, changing voltage of the coupled regulators as
* needed. It's up to the coupler to verify the voltage
* before changing it in hardware, i.e. coupler should
* check consumer's min/max and etc. This callback is
* optional and could be NULL, in which case a generic
* voltage balancer will be used.
*/
struct regulator_coupler {
struct list_head list;
int (*attach_regulator)(struct regulator_coupler *coupler,
struct regulator_dev *rdev);
int (*detach_regulator)(struct regulator_coupler *coupler,
struct regulator_dev *rdev);
int (*balance_voltage)(struct regulator_coupler *coupler,
struct regulator_dev *rdev,
suspend_state_t state);
};
#ifdef CONFIG_REGULATOR
int regulator_coupler_register(struct regulator_coupler *coupler);
#else
static inline int regulator_coupler_register(struct regulator_coupler *coupler)
{
return 0;
}
#endif
#endif
......@@ -15,8 +15,6 @@
#ifndef __LINUX_REGULATOR_DRIVER_H_
#define __LINUX_REGULATOR_DRIVER_H_
#define MAX_COUPLED 2
#include <linux/device.h>
#include <linux/notifier.h>
#include <linux/regulator/consumer.h>
......@@ -426,7 +424,8 @@ struct regulator_config {
* incremented.
*/
struct coupling_desc {
struct regulator_dev *coupled_rdevs[MAX_COUPLED];
struct regulator_dev **coupled_rdevs;
struct regulator_coupler *coupler;
int n_resolved;
int n_coupled;
};
......@@ -552,4 +551,5 @@ void regulator_unlock(struct regulator_dev *rdev);
*/
int regulator_desc_list_voltage_linear_range(const struct regulator_desc *desc,
unsigned int selector);
#endif
......@@ -156,7 +156,7 @@ struct regulation_constraints {
int system_load;
/* used for coupled regulators */
int max_spread;
u32 *max_spread;
/* used for changing voltage in steps */
int max_uV_step;
......
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