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Subject[PATCH v4 4/7] regulator: core: Parse coupled regulators properties
Date
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
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.

Add new structure "coupling_desc" to regulator_dev, which contains
pointers to all coupled regulators including the owner of the structure,
number of coupled regulators and counter of currently resolved
regulators.

Add of_functions to parse all data needed in regulator coupling.
Provide method to check DTS data consistency. Check if each coupled
regulator's max_spread is equal and if their lists of regulators match.

Signed-off-by: Maciej Purski <m.purski@samsung.com>
---
drivers/regulator/internal.h | 6 ++
drivers/regulator/of_regulator.c | 149 ++++++++++++++++++++++++++++++++++++++
include/linux/regulator/driver.h | 18 +++++
include/linux/regulator/machine.h | 4 +
4 files changed, 177 insertions(+)

diff --git a/drivers/regulator/internal.h b/drivers/regulator/internal.h
index abfd56e..f253a47 100644
--- a/drivers/regulator/internal.h
+++ b/drivers/regulator/internal.h
@@ -84,4 +84,10 @@ enum regulator_get_type {
struct regulator *_regulator_get(struct device *dev, const char *id,
enum regulator_get_type get_type);

+struct regulator_dev *of_parse_coupled_regulator(struct regulator_dev *rdev,
+ int index);
+
+int of_get_n_coupled(struct regulator_dev *rdev);
+
+bool of_check_coupling_data(struct regulator_dev *rdev);
#endif
diff --git a/drivers/regulator/of_regulator.c b/drivers/regulator/of_regulator.c
index caedd3d..e06b1af 100644
--- a/drivers/regulator/of_regulator.c
+++ b/drivers/regulator/of_regulator.c
@@ -138,6 +138,10 @@ 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;
+
constraints->over_current_protection = of_property_read_bool(np,
"regulator-over-current-protection");

@@ -392,3 +396,148 @@ struct regulator_dev *of_find_regulator_by_node(struct device_node *np)

return dev ? dev_to_rdev(dev) : NULL;
}
+
+/*
+ * Returns number of regulators coupled with rdev.
+ */
+int of_get_n_coupled(struct regulator_dev *rdev)
+{
+ struct device_node *node = rdev->dev.of_node;
+ int n_phandles;
+
+ n_phandles = of_count_phandle_with_args(node,
+ "regulator-coupled-with", 0);
+
+ return (n_phandles > 0) ? n_phandles : 0;
+}
+
+/* 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)
+{
+ int n_phandles, i;
+ bool found = false;
+
+ n_phandles = of_count_phandle_with_args(src,
+ "regulator-coupled-with", 0);
+
+ for (i = 0; i < n_phandles; i++) {
+ struct device_node *tmp = of_parse_phandle(src,
+ "regulator-coupled-with", i);
+
+ if (!tmp)
+ break;
+
+ /* found */
+ if (tmp == to_find)
+ found = true;
+
+ of_node_put(tmp);
+
+ if (found)
+ break;
+ }
+
+ return found;
+}
+
+/**
+ * of_check_coupling_data - Parse rdev's coupling properties and check data
+ * consistency
+ * @rdev - pointer to regulator_dev whose data is checked
+ *
+ * Function checks if all the following conditions are met:
+ * - rdev's max_spread is greater than 0
+ * - all coupled regulators have the same max_spread
+ * - all coupled regulators have the same number of regulator_dev phandles
+ * - all regulators are linked to each other
+ *
+ * Returns true if all conditions are met.
+ */
+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 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 c_max_spread, c_n_phandles;
+
+ c_node = of_parse_phandle(node,
+ "regulator-coupled-with", i);
+
+ if (!c_node)
+ ret = false;
+
+ c_n_phandles = of_count_phandle_with_args(c_node,
+ "regulator-coupled-with",
+ 0);
+
+ if (c_n_phandles != n_phandles) {
+ dev_err(&rdev->dev, "number of couped reg phandles mismatch\n");
+ ret = false;
+ goto clean;
+ }
+
+ if (of_property_read_u32(c_node, "regulator-coupled-max-spread",
+ &c_max_spread)) {
+ ret = false;
+ goto clean;
+ }
+
+ if (c_max_spread != max_spread) {
+ dev_err(&rdev->dev,
+ "coupled regulators max_spread mismatch\n");
+ ret = false;
+ goto clean;
+ }
+
+ if (!of_coupling_find_node(c_node, node)) {
+ dev_err(&rdev->dev, "missing 2-way linking for coupled regulators\n");
+ ret = false;
+ }
+
+clean:
+ of_node_put(c_node);
+ if (!ret)
+ break;
+ }
+
+ return ret;
+}
+
+/**
+ * of_parse_coupled regulator - Get regulator_dev pointer from rdev's property
+ * @rdev: Pointer to regulator_dev, whose DTS is used as a source to parse
+ * "regulator-coupled-with" property
+ * @index: Index in phandles array
+ *
+ * Returns the regulator_dev pointer parsed from DTS. If it has not been yet
+ * registered, returns NULL
+ */
+struct regulator_dev *of_parse_coupled_regulator(struct regulator_dev *rdev,
+ int index)
+{
+ struct device_node *node = rdev->dev.of_node;
+ struct device_node *c_node;
+ struct regulator_dev *c_rdev;
+
+ c_node = of_parse_phandle(node, "regulator-coupled-with", index);
+ if (!c_node)
+ return NULL;
+
+ c_rdev = of_find_regulator_by_node(c_node);
+
+ of_node_put(c_node);
+
+ return c_rdev;
+}
diff --git a/include/linux/regulator/driver.h b/include/linux/regulator/driver.h
index 94417b4..ed0d0d8 100644
--- a/include/linux/regulator/driver.h
+++ b/include/linux/regulator/driver.h
@@ -15,6 +15,8 @@
#ifndef __LINUX_REGULATOR_DRIVER_H_
#define __LINUX_REGULATOR_DRIVER_H_

+#define MAX_COUPLED 10
+
#include <linux/device.h>
#include <linux/notifier.h>
#include <linux/regulator/consumer.h>
@@ -402,6 +404,20 @@ struct regulator_config {
};

/*
+ * struct coupling_desc
+ *
+ * Describes coupling of regulators. Each regulator should have
+ * at least a pointer to itself in coupled_rdevs array.
+ * When a new coupled regulator is resolved, n_resolved is
+ * incremented.
+ */
+struct coupling_desc {
+ struct regulator_dev *coupled_rdevs[MAX_COUPLED];
+ int n_resolved;
+ int n_coupled;
+};
+
+/*
* struct regulator_dev
*
* Voltage / Current regulator class device. One for each
@@ -424,6 +440,8 @@ struct regulator_dev {
/* lists we own */
struct list_head consumer_list; /* consumers we supply */

+ struct coupling_desc coupling_desc;
+
struct blocking_notifier_head notifier;
struct mutex mutex; /* consumer lock */
struct module *owner;
diff --git a/include/linux/regulator/machine.h b/include/linux/regulator/machine.h
index e50519f..e3a4d84 100644
--- a/include/linux/regulator/machine.h
+++ b/include/linux/regulator/machine.h
@@ -91,6 +91,7 @@ struct regulator_state {
* @ilim_uA: Maximum input current.
* @system_load: Load that isn't captured by any consumer requests.
*
+ * @max_spread: Max possible spread between coupled regulators
* @valid_modes_mask: Mask of modes which may be configured by consumers.
* @valid_ops_mask: Operations which may be performed by consumers.
*
@@ -142,6 +143,9 @@ struct regulation_constraints {

int system_load;

+ /* used for coupled regulators */
+ int max_spread;
+
/* valid regulator operating modes for this machine */
unsigned int valid_modes_mask;

--
2.7.4
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