Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-10 06:01:57 +00:00
Code Issues Packages Projects Releases Wiki Activity

mfd: syscon: Add of_syscon_register_regmap() API

Browse Source 
The of_syscon_register_regmap() API allows an externally created regmap
to be registered with syscon. This regmap can then be returned to client
drivers using the syscon_regmap_lookup_by_phandle() APIs.

The API is used by platforms where mmio access to the syscon registers is
not possible, and a underlying soc driver like exynos-pmu provides a SoC
specific regmap that can issue a SMC or hypervisor call to write the
register.

This approach keeps the SoC complexities out of syscon, but allows common
drivers such as  syscon-poweroff, syscon-reboot and friends that are used
by many SoCs already to be re-used.

Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org>
Tested-by: Will McVicker <willmcvicker@google.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240621115544.1655458-2-peter.griffin@linaro.org
Signed-off-by: Lee Jones <lee@kernel.org>
This commit is contained in:
Peter Griffin 2024-06-21 12:55:43 +01:00 committed by Lee Jones
parent 1613e604df
commit 769cb63166
2 changed files with 56 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

48
drivers/mfd/syscon.c
View File

@ -192,6 +192,54 @@ static struct regmap *device_node_get_regmap(struct device_node *np,
return syscon->regmap;
}
/**
* of_syscon_register_regmap() - Register regmap for specified device node
* @np: Device tree node
* @regmap: Pointer to regmap object
*
* Register an externally created regmap object with syscon for the specified
* device tree node. This regmap will then be returned to client drivers using
* the syscon_regmap_lookup_by_phandle() API.
*
* Return: 0 on success, negative error code on failure.
*/
int of_syscon_register_regmap(struct device_node *np, struct regmap *regmap)
{
struct syscon *entry, *syscon = NULL;
int ret;
if (!np || !regmap)
return -EINVAL;
syscon = kzalloc(sizeof(*syscon), GFP_KERNEL);
if (!syscon)
return -ENOMEM;
/* check if syscon entry already exists */
spin_lock(&syscon_list_slock);
list_for_each_entry(entry, &syscon_list, list)
if (entry->np == np) {
ret = -EEXIST;
goto err_unlock;
}
syscon->regmap = regmap;
syscon->np = np;
/* register the regmap in syscon list */
list_add_tail(&syscon->list, &syscon_list);
spin_unlock(&syscon_list_slock);
return 0;
err_unlock:
spin_unlock(&syscon_list_slock);
kfree(syscon);
return ret;
}
EXPORT_SYMBOL_GPL(of_syscon_register_regmap);
struct regmap *device_node_to_regmap(struct device_node *np)
{
return device_node_get_regmap(np, false);

8
include/linux/mfd/syscon.h
View File

@ -28,6 +28,8 @@ struct regmap *syscon_regmap_lookup_by_phandle_args(struct device_node *np,
unsigned int *out_args);
struct regmap *syscon_regmap_lookup_by_phandle_optional(struct device_node *np,
const char *property);
int of_syscon_register_regmap(struct device_node *np,
struct regmap *regmap);
#else
static inline struct regmap *device_node_to_regmap(struct device_node *np)
{
@ -67,6 +69,12 @@ static inline struct regmap *syscon_regmap_lookup_by_phandle_optional(
return NULL;
}
static inline int of_syscon_register_regmap(struct device_node *np,
struct regmap *regmap)
{
return -EOPNOTSUPP;
}
#endif
#endif /* __LINUX_MFD_SYSCON_H__ */