[RFC PATCH 4/4] mfd: syscon: add ACPI support

Kefeng Wang
2015-12-02T09:12:21Z

This enables syscon with ACPI support.
syscon_regmap_lookup_by_dev_property() function was added. With helper
device_get_reference_node() and acpi_dev_find_plat_dev(), it can be used
in both DT and ACPI.

The device driver can obtain syscon using _DSD method in DSDT, an example
is shown below.

Device(CTL0) {
Name(_HID, "HISI0061")
Name(_CRS, ResourceTemplate() {
Memory32Fixed(ReadWrite, 0x80000000, 0x10000)
})
}

Device(DEV0) {
Name(_HID, "HISI00B1")
Name(_CRS, ResourceTemplate() {
Memory32Fixed(ReadWrite, 0x8c030000, 0x10000)
Interrupt(ResourceConsumer, Level, ActiveHigh, Exclusive){ 192 }
})

Name (_DSD, Package () {
ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
Package () {
Package () {"syscon",Package() {\_SB.CTL0} }
}
})
}

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
drivers/mfd/syscon.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++
include/linux/mfd/syscon.h | 8 ++++++++
2 files changed, 58 insertions(+)

diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
index 176bf0f..6f23418 100644
--- a/drivers/mfd/syscon.c
+++ b/drivers/mfd/syscon.c
@@ -12,6 +12,7 @@
* (at your option) any later version.
*/

+#include <linux/acpi.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/module.h>
@@ -21,6 +22,7 @@
#include <linux/of_platform.h>
#include <linux/platform_data/syscon.h>
#include <linux/platform_device.h>
+#include <linux/property.h>
#include <linux/regmap.h>
#include <linux/mfd/syscon.h>
#include <linux/slab.h>
@@ -174,6 +176,47 @@ struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
}
EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);

+struct regmap *syscon_regmap_lookup_by_dev_property(struct device *dev,
+ const char *propname)
+{
+ struct fwnode_handle *fwnode;
+ struct regmap *regmap = NULL;
+
+ fwnode = device_get_reference_node(dev, propname, 0);
+
+ if (IS_ENABLED(CONFIG_OF) && dev->of_node) {
+ struct device_node *syscon_np;
+ if (propname)
+ syscon_np = to_of_node(fwnode);
+ else
+ syscon_np = dev->of_node;
+ if (!syscon_np)
+ return ERR_PTR(-ENODEV);
+ regmap = syscon_node_to_regmap(syscon_np);
+ of_node_put(syscon_np);
+ } else if (IS_ENABLED(CONFIG_ACPI)) {
+ struct platform_device *pdev;
+ struct acpi_device *adev;
+ struct syscon *syscon;
+
+ adev = to_acpi_device_node(fwnode);
+ if (!adev)
+ return ERR_PTR(-ENODEV);
+
+ pdev = acpi_dev_find_plat_dev(adev);
+ if (!pdev)
+ return ERR_PTR(-ENODEV);
+
+ syscon = platform_get_drvdata(pdev);
+ if (!syscon)
+ return ERR_PTR(-ENODEV);
+
+ regmap = syscon->regmap;
+ }
+ return regmap;
+}
+EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_dev_property);
+
static int syscon_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
@@ -216,9 +259,16 @@ static const struct platform_device_id syscon_ids[] = {
{ }
};

+static const struct acpi_device_id syscon_acpi_match[] = {
+ { "HISI0061", 0 }, /* better to use generic ACPI ID */
+ { }
+};
+MODULE_DEVICE_TABLE(acpi, syscon_acpi_match);
+
static struct platform_driver syscon_driver = {
.driver = {
.name = "syscon",
+ .acpi_match_table = ACPI_PTR(syscon_acpi_match),
},
.probe = syscon_probe,
.id_table = syscon_ids,
diff --git a/include/linux/mfd/syscon.h b/include/linux/mfd/syscon.h
index 75e543b..db79ca2 100644
--- a/include/linux/mfd/syscon.h
+++ b/include/linux/mfd/syscon.h
@@ -17,6 +17,7 @@

#include <linux/err.h>

+struct device;
struct device_node;

#ifdef CONFIG_MFD_SYSCON
@@ -26,6 +27,8 @@ extern struct regmap *syscon_regmap_lookup_by_pdevname(const char *s);
extern struct regmap *syscon_regmap_lookup_by_phandle(
struct device_node *np,
const char *property);
+extern struct regmap *syscon_regmap_lookup_by_dev_property(struct device *dev,
+ const char *propname);
#else
static inline struct regmap *syscon_node_to_regmap(struct device_node *np)
{
@@ -48,6 +51,11 @@ static inline struct regmap *syscon_regmap_lookup_by_phandle(
{
return ERR_PTR(-ENOSYS);
}
+static inline struct regmap *syscon_regmap_lookup_by_dev_property(struct device *dev,
+ const char *propname);
+{
+ return ERR_PTR(-ENOSYS);
+}
#endif

#endif /* __LINUX_MFD_SYSCON_H__ */
--
1.7.12.4