PM: domains: Add helper functions to attach/detach multiple PM domains

Attaching/detaching of a device to multiple PM domains has started to
become a common operation for many drivers, typically during ->probe() and
->remove(). In most cases, this has lead to lots of boilerplate code in the
drivers.

To fixup up the situation, let's introduce a pair of helper functions,
dev_pm_domain_attach|detach_list(), that driver can use instead of the
open-coding. Note that, it seems reasonable to limit the support for these
helpers to DT based platforms, at it's the only valid use case for now.

Suggested-by: Daniel Baluta <daniel.baluta@nxp.com>
Tested-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Tested-by: Iuliana Prodan <iuliana.prodan@nxp.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20240130123951.236243-2-ulf.hansson@linaro.org

1 files changed, 38 insertions, 0 deletions

diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index b97c5e9820f9..fb91770ba4ba 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -20,6 +20,33 @@
 #include <linux/time64.h>
 
 /*
+ * Flags to control the behaviour when attaching a device to its PM domains.
+ *
+ * PD_FLAG_NO_DEV_LINK:		As the default behaviour creates a device-link
+ *				for every PM domain that gets attached, this
+ *				flag can be used to skip that.
+ *
+ * PD_FLAG_DEV_LINK_ON:		Add the DL_FLAG_RPM_ACTIVE to power-on the
+ *				supplier and its PM domain when creating the
+ *				device-links.
+ *
+ */
+#define PD_FLAG_NO_DEV_LINK		BIT(0)
+#define PD_FLAG_DEV_LINK_ON		BIT(1)
+
+struct dev_pm_domain_attach_data {
+	const char * const *pd_names;
+	const u32 num_pd_names;
+	const u32 pd_flags;
+};
+
+struct dev_pm_domain_list {
+	struct device **pd_devs;
+	struct device_link **pd_links;
+	u32 num_pds;
+};
+
+/*
  * Flags to control the behaviour of a genpd.
  *
  * These flags may be set in the struct generic_pm_domain's flags field by a
@@ -420,7 +447,11 @@ struct device *dev_pm_domain_attach_by_id(struct device *dev,
 					  unsigned int index);
 struct device *dev_pm_domain_attach_by_name(struct device *dev,
 					    const char *name);
+int dev_pm_domain_attach_list(struct device *dev,
+			      const struct dev_pm_domain_attach_data *data,
+			      struct dev_pm_domain_list **list);
 void dev_pm_domain_detach(struct device *dev, bool power_off);
+void dev_pm_domain_detach_list(struct dev_pm_domain_list *list);
 int dev_pm_domain_start(struct device *dev);
 void dev_pm_domain_set(struct device *dev, struct dev_pm_domain *pd);
 int dev_pm_domain_set_performance_state(struct device *dev, unsigned int state);
@@ -439,7 +470,14 @@ static inline struct device *dev_pm_domain_attach_by_name(struct device *dev,
 {
 	return NULL;
 }
+static inline int dev_pm_domain_attach_list(struct device *dev,
+				const struct dev_pm_domain_attach_data *data,
+				struct dev_pm_domain_list **list)
+{
+	return 0;
+}
 static inline void dev_pm_domain_detach(struct device *dev, bool power_off) {}
+static inline void dev_pm_domain_detach_list(struct dev_pm_domain_list *list) {}
 static inline int dev_pm_domain_start(struct device *dev)
 {
 	return 0;