soc: samsung: pmu: Provide global function to get PMU regmap

PMU is something like a SoC wide service, so add a helper function to get
PMU regmap. This will be used by other Exynos device drivers. This way it
can be avoided to model this dependency in device tree (as phandles to PMU
node) for almost every device in the SoC.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Tomasz Figa <tomasz.figa@gmail.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

drivers/soc/samsung/exynos-pmu.c

@@ -11,6 +11,7 @@
 
 #include <linux/of.h>
 #include <linux/of_address.h>
+#include <linux/mfd/syscon.h>
 #include <linux/platform_device.h>
 #include <linux/delay.h>
 
@@ -92,6 +93,16 @@ static const struct of_device_id exynos_pmu_of_device_ids[] = {
 	{ /*sentinel*/ },
 };
 
+struct regmap *exynos_get_pmu_regmap(void)
+{
+	struct device_node *np = of_find_matching_node(NULL,
+						      exynos_pmu_of_device_ids);
+	if (np)
+		return syscon_node_to_regmap(np);
+	return ERR_PTR(-ENODEV);
+}
+EXPORT_SYMBOL_GPL(exynos_get_pmu_regmap);
+
 static int exynos_pmu_probe(struct platform_device *pdev)
 {
 	const struct of_device_id *match;

include/linux/soc/samsung/exynos-pmu.h

@@ -12,6 +12,8 @@
 #ifndef __LINUX_SOC_EXYNOS_PMU_H
 #define __LINUX_SOC_EXYNOS_PMU_H
 
+struct regmap;
+
 enum sys_powerdown {
 	SYS_AFTR,
 	SYS_LPA,
@@ -20,5 +22,13 @@ enum sys_powerdown {
 };
 
 extern void exynos_sys_powerdown_conf(enum sys_powerdown mode);
+#ifdef CONFIG_EXYNOS_PMU
+extern struct regmap *exynos_get_pmu_regmap(void);
+#else
+static inline struct regmap *exynos_get_pmu_regmap(void)
+{
+	return ERR_PTR(-ENODEV);
+}
+#endif
 
 #endif /* __LINUX_SOC_EXYNOS_PMU_H */