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Date: Fri, 19 Jan 2018 21:20:19 -0600
From: David Lechner <david@...hnology.com>
To: linux-arm-kernel@...ts.infradead.org
Cc: David Lechner <david@...hnology.com>, Sekhar Nori <nsekhar@...com>,
Kevin Hilman <khilman@...nel.org>,
Lee Jones <lee.jones@...aro.org>,
Arnd Bergmann <arnd@...db.de>,
Kishon Vijay Abraham I <kishon@...com>,
Adam Ford <aford173@...il.com>,
Bartosz Golaszewski <bgolaszewski@...libre.com>,
linux-kernel@...r.kernel.org
Subject: [PATCH 1/6] mfd: syscon: Add syscon_register() function
This adds a new syscon_register() function that creates a new syscon
regmap and adds it to the lookup list.
This function serves two purposes:
1. This is needed for platforms without device tree support where the
syscon regmap is needed in early boot (e.g. clocks), because using a
platform driver at this point in boot is not an option.
2. It allows other drivers to use syscon_regmap_lookup_by_compatible()
for both device tree and non-DT platforms instead of having to have
a separate case that calls syscon_regmap_lookup_by_pdevname().
Signed-off-by: David Lechner <david@...hnology.com>
---
drivers/mfd/syscon.c | 71 ++++++++++++++++++++++++++++++++++++++++++++++
include/linux/mfd/syscon.h | 9 ++++++
2 files changed, 80 insertions(+)
diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
index b93fe4c..ab086b1 100644
--- a/drivers/mfd/syscon.c
+++ b/drivers/mfd/syscon.c
@@ -25,6 +25,8 @@
#include <linux/mfd/syscon.h>
#include <linux/slab.h>
+#define SYSCON_COMPATIBLE_SIZE 50
+
static struct platform_driver syscon_driver;
static DEFINE_SPINLOCK(syscon_list_slock);
@@ -34,6 +36,7 @@ struct syscon {
struct device_node *np;
struct regmap *regmap;
struct list_head list;
+ char compatible[SYSCON_COMPATIBLE_SIZE];
};
static const struct regmap_config syscon_regmap_config = {
@@ -140,9 +143,27 @@ EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
{
+ struct syscon *entry, *syscon = NULL;
struct device_node *syscon_np;
struct regmap *regmap;
+ spin_lock(&syscon_list_slock);
+
+ /* Check for entries registered with syscon_register() */
+ list_for_each_entry(entry, &syscon_list, list) {
+ if (!entry->compatible)
+ continue;
+ if (!strncmp(entry->compatible, s, SYSCON_COMPATIBLE_SIZE)) {
+ syscon = entry;
+ break;
+ }
+ }
+
+ spin_unlock(&syscon_list_slock);
+
+ if (syscon)
+ return syscon->regmap;
+
syscon_np = of_find_compatible_node(NULL, NULL, s);
if (!syscon_np)
return ERR_PTR(-ENODEV);
@@ -196,6 +217,56 @@ struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
}
EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
+/**
+ * syscon_register - Register a new syscon regmap
+ * @start: The starting memory address of the regmap
+ * @size: The size of the regmap in bytes
+ * @compatible: Compatible string used for lookup
+ *
+ * Returns: Pointer to a regmap or a negative error code.
+ */
+struct regmap *syscon_register(resource_size_t start, size_t size,
+ const char *compatible)
+{
+ struct regmap_config syscon_config = syscon_regmap_config;
+ struct syscon *syscon;
+ void __iomem *base;
+ int err;
+
+ syscon = kzalloc(sizeof(*syscon), GFP_KERNEL);
+ if (!syscon)
+ return ERR_PTR(-ENOMEM);
+
+ base = ioremap(start, size);
+ if (!base) {
+ err = -ENOMEM;
+ goto err_free_syscon;
+ }
+
+ strncpy(syscon->compatible, compatible, SYSCON_COMPATIBLE_SIZE);
+
+ syscon_config.max_register = size - 1;
+ syscon->regmap = regmap_init_mmio(NULL, base, &syscon_config);
+ if (IS_ERR(syscon->regmap)) {
+ err = PTR_ERR(syscon->regmap);
+ goto err_iounmap;
+ }
+
+ spin_lock(&syscon_list_slock);
+ list_add_tail(&syscon->list, &syscon_list);
+ spin_unlock(&syscon_list_slock);
+
+ return syscon->regmap;
+
+err_iounmap:
+ iounmap(base);
+err_free_syscon:
+ kfree(syscon);
+
+ return ERR_PTR(err);
+}
+EXPORT_SYMBOL_GPL(syscon_register);
+
static int syscon_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
diff --git a/include/linux/mfd/syscon.h b/include/linux/mfd/syscon.h
index 40a76b9..ce531b4 100644
--- a/include/linux/mfd/syscon.h
+++ b/include/linux/mfd/syscon.h
@@ -27,6 +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_register(resource_size_t start, size_t size,
+ const char *compatible);
#else
static inline struct regmap *syscon_node_to_regmap(struct device_node *np)
{
@@ -49,6 +51,13 @@ static inline struct regmap *syscon_regmap_lookup_by_phandle(
{
return ERR_PTR(-ENOTSUPP);
}
+
+static inline struct regmap *syscon_register(resource_size_t start,
+ size_t size,
+ const char *id)
+{
+ return ERR_PTR(-ENOTSUPP);
+}
#endif
#endif /* __LINUX_MFD_SYSCON_H__ */
--
2.7.4
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