[PATCH] mfd: syscon: Decouple syscon interface from syscon devices
Pankaj Dubey
pankaj.dubey at samsung.com
Fri Aug 22 01:09:51 PDT 2014
From: Tomasz Figa <t.figa at samsung.com>
Currently a syscon entity can be only registered directly through a
platform device that binds to a dedicated driver. However in certain use
cases it is desirable to make a device used with another driver a syscon
interface provider. For example, certain SoCs (e.g. Exynos) contain
system controller blocks which perform various functions such as power
domain control, CPU power management, low power mode control, but in
addition contain certain IP integration glue, such as various signal
masks, coprocessor power control, etc. In such case, there is a need to
have a dedicated driver for such system controller but also share
registers with other drivers. The latter is where the syscon interface
is helpful.
This patch decouples syscon object from syscon driver, so that it can be
registered from any driver in addition to the original "syscon" platform
driver.
Signed-off-by: Tomasz Figa <t.figa at samsung.com>
Signed-off-by: Pankaj Dubey <pankaj.dubey at samsung.com>
---
RFC patch [1] was posted by Tomasz Figa. This patch addresses some of
comments given by Arnd to RFC patch, and further decouples syscon from
device model. It also gives flexibility of registering with syscon at
early stage using device_node object.
[1]: https://lkml.org/lkml/2014/6/17/331
drivers/mfd/syscon.c | 112 ++++++++++++++++++++++++++++----------------
include/linux/mfd/syscon.h | 14 ++++++
2 files changed, 86 insertions(+), 40 deletions(-)
diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
index ca15878..a91db30 100644
--- a/drivers/mfd/syscon.c
+++ b/drivers/mfd/syscon.c
@@ -14,6 +14,7 @@
#include <linux/err.h>
#include <linux/io.h>
+#include <linux/list.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_address.h>
@@ -22,33 +23,32 @@
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/mfd/syscon.h>
+#include <linux/slab.h>
-static struct platform_driver syscon_driver;
+static DEFINE_SPINLOCK(syscon_list_slock);
+static LIST_HEAD(syscon_list);
struct syscon {
+ struct device_node *np;
struct regmap *regmap;
+ struct list_head list;
};
-static int syscon_match_node(struct device *dev, void *data)
-{
- struct device_node *dn = data;
-
- return (dev->of_node == dn) ? 1 : 0;
-}
-
struct regmap *syscon_node_to_regmap(struct device_node *np)
{
- struct syscon *syscon;
- struct device *dev;
+ struct syscon *entry, *syscon = NULL;
- dev = driver_find_device(&syscon_driver.driver, NULL, np,
- syscon_match_node);
- if (!dev)
- return ERR_PTR(-EPROBE_DEFER);
+ spin_lock(&syscon_list_slock);
- syscon = dev_get_drvdata(dev);
+ list_for_each_entry(entry, &syscon_list, list)
+ if (entry->np == np) {
+ syscon = entry;
+ break;
+ }
- return syscon->regmap;
+ spin_unlock(&syscon_list_slock);
+
+ return syscon ? syscon->regmap : ERR_PTR(-EPROBE_DEFER);
}
EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
@@ -68,24 +68,22 @@ struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
}
EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
-static int syscon_match_pdevname(struct device *dev, void *data)
-{
- return !strcmp(dev_name(dev), (const char *)data);
-}
-
struct regmap *syscon_regmap_lookup_by_pdevname(const char *s)
{
- struct device *dev;
- struct syscon *syscon;
-
- dev = driver_find_device(&syscon_driver.driver, NULL, (void *)s,
- syscon_match_pdevname);
- if (!dev)
- return ERR_PTR(-EPROBE_DEFER);
-
- syscon = dev_get_drvdata(dev);
+ struct syscon *entry, *syscon = NULL;
+ struct platform_device *pdev = NULL;
+
+ spin_lock(&syscon_list_slock);
+ list_for_each_entry(entry, &syscon_list, list) {
+ pdev = of_find_device_by_node(entry->np);
+ if (pdev && !strcmp(dev_name(&pdev->dev), s)) {
+ syscon = entry;
+ break;
+ }
+ }
+ spin_unlock(&syscon_list_slock);
- return syscon->regmap;
+ return syscon ? syscon->regmap : ERR_PTR(-EPROBE_DEFER);
}
EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_pdevname);
@@ -121,17 +119,49 @@ static struct regmap_config syscon_regmap_config = {
.reg_stride = 4,
};
+void of_syscon_unregister(struct device_node *np)
+{
+ struct syscon *entry;
+
+ spin_lock(&syscon_list_slock);
+
+ list_for_each_entry(entry, &syscon_list, list)
+ if (entry->np == np) {
+ list_del(&entry->list);
+ break;
+ }
+
+ spin_unlock(&syscon_list_slock);
+}
+EXPORT_SYMBOL_GPL(of_syscon_unregister);
+
+int of_syscon_register(struct device_node *np, struct regmap *regmap)
+{
+ struct syscon *syscon;
+
+ syscon = kzalloc(sizeof(*syscon), GFP_KERNEL);
+ if (!syscon)
+ return -ENOMEM;
+
+ syscon->regmap = regmap;
+ syscon->np = np;
+
+ spin_lock(&syscon_list_slock);
+ list_add_tail(&syscon->list, &syscon_list);
+ spin_unlock(&syscon_list_slock);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(of_syscon_register);
+
static int syscon_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct syscon_platform_data *pdata = dev_get_platdata(dev);
- struct syscon *syscon;
+ struct regmap *regmap;
struct resource *res;
void __iomem *base;
-
- syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
- if (!syscon)
- return -ENOMEM;
+ int ret;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res)
@@ -144,14 +174,16 @@ static int syscon_probe(struct platform_device *pdev)
syscon_regmap_config.max_register = res->end - res->start - 3;
if (pdata)
syscon_regmap_config.name = pdata->label;
- syscon->regmap = devm_regmap_init_mmio(dev, base,
+ regmap = devm_regmap_init_mmio(dev, base,
&syscon_regmap_config);
- if (IS_ERR(syscon->regmap)) {
+ if (IS_ERR(regmap)) {
dev_err(dev, "regmap init failed\n");
- return PTR_ERR(syscon->regmap);
+ return PTR_ERR(regmap);
}
- platform_set_drvdata(pdev, syscon);
+ ret = of_syscon_register(dev->of_node, regmap);
+ if (ret)
+ return ret;
dev_dbg(dev, "regmap %pR registered\n", res);
diff --git a/include/linux/mfd/syscon.h b/include/linux/mfd/syscon.h
index 75e543b..dc2807b 100644
--- a/include/linux/mfd/syscon.h
+++ b/include/linux/mfd/syscon.h
@@ -18,8 +18,12 @@
#include <linux/err.h>
struct device_node;
+struct regmap;
#ifdef CONFIG_MFD_SYSCON
+extern int of_syscon_register(struct device_node *np, struct regmap *regmap);
+extern void of_syscon_unregister(struct device_node *np);
+
extern struct regmap *syscon_node_to_regmap(struct device_node *np);
extern struct regmap *syscon_regmap_lookup_by_compatible(const char *s);
extern struct regmap *syscon_regmap_lookup_by_pdevname(const char *s);
@@ -27,6 +31,16 @@ extern struct regmap *syscon_regmap_lookup_by_phandle(
struct device_node *np,
const char *property);
#else
+static inline int of_syscon_register(struct device_node *np,
+ struct regmap *regmap)
+{
+ return -ENOSYS;
+}
+
+static inline void of_syscon_unregister(struct device_node *np)
+{
+}
+
static inline struct regmap *syscon_node_to_regmap(struct device_node *np)
{
return ERR_PTR(-ENOSYS);
--
1.7.9.5
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