linux/drivers/regulator/of_regulator.c
Stephen Warren a2f95c3637 regulator: clear state each invocation of of_regulator_match
of_regulator_match() saves some dynamcially allocated state into the
match table that's passed to it. By implementation and not contract, for
each match table entry, if non-NULL state is already present,
of_regulator_match() will not overwrite it. of_regulator_match() is
typically called each time a regulator is probe()d. This means it is
called with the same match table over and over again if a regulator
triggers deferred probe. This results in stale, kfree()d data being left
in the match table from probe to probe, which causes a variety of crashes
or use of invalid data.

Explicitly free all output state from of_regulator_match() before
generating new results in order to avoid this.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: stable@vger.kernel.org
2013-01-30 10:11:06 +08:00

159 lines
4.8 KiB
C

/*
* OF helpers for regulator framework
*
* Copyright (C) 2011 Texas Instruments, Inc.
* Rajendra Nayak <rnayak@ti.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/regulator/machine.h>
#include <linux/regulator/of_regulator.h>
static void of_get_regulation_constraints(struct device_node *np,
struct regulator_init_data **init_data)
{
const __be32 *min_uV, *max_uV, *uV_offset;
const __be32 *min_uA, *max_uA, *ramp_delay;
struct regulation_constraints *constraints = &(*init_data)->constraints;
constraints->name = of_get_property(np, "regulator-name", NULL);
min_uV = of_get_property(np, "regulator-min-microvolt", NULL);
if (min_uV)
constraints->min_uV = be32_to_cpu(*min_uV);
max_uV = of_get_property(np, "regulator-max-microvolt", NULL);
if (max_uV)
constraints->max_uV = be32_to_cpu(*max_uV);
/* Voltage change possible? */
if (constraints->min_uV != constraints->max_uV)
constraints->valid_ops_mask |= REGULATOR_CHANGE_VOLTAGE;
/* Only one voltage? Then make sure it's set. */
if (min_uV && max_uV && constraints->min_uV == constraints->max_uV)
constraints->apply_uV = true;
uV_offset = of_get_property(np, "regulator-microvolt-offset", NULL);
if (uV_offset)
constraints->uV_offset = be32_to_cpu(*uV_offset);
min_uA = of_get_property(np, "regulator-min-microamp", NULL);
if (min_uA)
constraints->min_uA = be32_to_cpu(*min_uA);
max_uA = of_get_property(np, "regulator-max-microamp", NULL);
if (max_uA)
constraints->max_uA = be32_to_cpu(*max_uA);
/* Current change possible? */
if (constraints->min_uA != constraints->max_uA)
constraints->valid_ops_mask |= REGULATOR_CHANGE_CURRENT;
if (of_find_property(np, "regulator-boot-on", NULL))
constraints->boot_on = true;
if (of_find_property(np, "regulator-always-on", NULL))
constraints->always_on = true;
else /* status change should be possible if not always on. */
constraints->valid_ops_mask |= REGULATOR_CHANGE_STATUS;
ramp_delay = of_get_property(np, "regulator-ramp-delay", NULL);
if (ramp_delay)
constraints->ramp_delay = be32_to_cpu(*ramp_delay);
}
/**
* of_get_regulator_init_data - extract regulator_init_data structure info
* @dev: device requesting for regulator_init_data
*
* Populates regulator_init_data structure by extracting data from device
* tree node, returns a pointer to the populated struture or NULL if memory
* alloc fails.
*/
struct regulator_init_data *of_get_regulator_init_data(struct device *dev,
struct device_node *node)
{
struct regulator_init_data *init_data;
if (!node)
return NULL;
init_data = devm_kzalloc(dev, sizeof(*init_data), GFP_KERNEL);
if (!init_data)
return NULL; /* Out of memory? */
of_get_regulation_constraints(node, &init_data);
return init_data;
}
EXPORT_SYMBOL_GPL(of_get_regulator_init_data);
/**
* of_regulator_match - extract multiple regulator init data from device tree.
* @dev: device requesting the data
* @node: parent device node of the regulators
* @matches: match table for the regulators
* @num_matches: number of entries in match table
*
* This function uses a match table specified by the regulator driver to
* parse regulator init data from the device tree. @node is expected to
* contain a set of child nodes, each providing the init data for one
* regulator. The data parsed from a child node will be matched to a regulator
* based on either the deprecated property regulator-compatible if present,
* or otherwise the child node's name. Note that the match table is modified
* in place.
*
* Returns the number of matches found or a negative error code on failure.
*/
int of_regulator_match(struct device *dev, struct device_node *node,
struct of_regulator_match *matches,
unsigned int num_matches)
{
unsigned int count = 0;
unsigned int i;
const char *name;
struct device_node *child;
if (!dev || !node)
return -EINVAL;
for (i = 0; i < num_matches; i++) {
struct of_regulator_match *match = &matches[i];
match->init_data = NULL;
match->of_node = NULL;
}
for_each_child_of_node(node, child) {
name = of_get_property(child,
"regulator-compatible", NULL);
if (!name)
name = child->name;
for (i = 0; i < num_matches; i++) {
struct of_regulator_match *match = &matches[i];
if (match->of_node)
continue;
if (strcmp(match->name, name))
continue;
match->init_data =
of_get_regulator_init_data(dev, child);
if (!match->init_data) {
dev_err(dev,
"failed to parse DT for regulator %s\n",
child->name);
return -EINVAL;
}
match->of_node = child;
count++;
break;
}
}
return count;
}
EXPORT_SYMBOL_GPL(of_regulator_match);