[PATCH v3] regulator: event: Add regulator netlink event support

From: Naresh Solanki
Date: Tue Nov 28 2023 - 09:10:08 EST

This commit introduces netlink event support to the regulator subsystem.

Changes:
- Introduce event.c and regnl.h for netlink event handling.
- Implement reg_generate_netlink_event to broadcast regulator events.
- Update Makefile to include the new event.c file.

Signed-off-by: Naresh Solanki <naresh.solanki@xxxxxxxxxxxxx>

---
Chagnes in V3:
- Add Kconfig option REGULATOR_NETLINK_EVENTS for regulator netlink
support
- Add mechanism to avoid regulator name duplication
- Add UAPI header for regulator with define's for regulator events &
netlink.
---
drivers/regulator/Kconfig | 10 ++++
drivers/regulator/Makefile | 1 +
drivers/regulator/core.c | 19 ++++++-
drivers/regulator/event.c | 86 ++++++++++++++++++++++++++++++
drivers/regulator/regnl.h | 8 +++
include/linux/regulator/consumer.h | 47 +---------------
include/uapi/regulator/regulator.h | 85 +++++++++++++++++++++++++++++
7 files changed, 209 insertions(+), 47 deletions(-)
create mode 100644 drivers/regulator/event.c
create mode 100644 drivers/regulator/regnl.h
create mode 100644 include/uapi/regulator/regulator.h

diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index f3ec24691378..00d3898ee599 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -56,6 +56,16 @@ config REGULATOR_USERSPACE_CONSUMER

If unsure, say no.

+config REGULATOR_NETLINK_EVENTS
+ tristate "Enable support for receiving regulator events via netlink"
+ depends on NET
+ help
+ Enabling this option allows the kernel to broadcast regulator events using
+ the netlink mechanism. User-space applications can subscribe to these events
+ for real-time updates on various regulator events.
+
+ If unsure, say no.
+
config REGULATOR_88PG86X
tristate "Marvell 88PG86X voltage regulators"
depends on I2C
diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
index b2b059b5ee56..46fb569e6be8 100644
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile
@@ -5,6 +5,7 @@


obj-$(CONFIG_REGULATOR) += core.o dummy.o fixed-helper.o helpers.o devres.o irq_helpers.o
+obj-$(CONFIG_REGULATOR_NETLINK_EVENTS) += event.o
obj-$(CONFIG_OF) += of_regulator.o
obj-$(CONFIG_REGULATOR_FIXED_VOLTAGE) += fixed.o
obj-$(CONFIG_REGULATOR_VIRTUAL_CONSUMER) += virtual.o
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 4aa9ec8c22f3..a968dabb48f5 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -33,6 +33,7 @@

#include "dummy.h"
#include "internal.h"
+#include "regnl.h"

static DEFINE_WW_CLASS(regulator_ww_class);
static DEFINE_MUTEX(regulator_nesting_mutex);
@@ -4854,7 +4855,23 @@ static int _notifier_call_chain(struct regulator_dev *rdev,
unsigned long event, void *data)
{
/* call rdev chain first */
- return blocking_notifier_call_chain(&rdev->notifier, event, data);
+ int ret = blocking_notifier_call_chain(&rdev->notifier, event, data);
+
+ if (IS_REACHABLE(CONFIG_REGULATOR_NETLINK_EVENTS)) {
+ struct device *parent = rdev->dev.parent;
+ const char *rname = rdev_get_name(rdev);
+ char name[32];
+
+ /* Avoid duplicate debugfs directory names */
+ if (parent && rname == rdev->desc->name) {
+ snprintf(name, sizeof(name), "%s-%s", dev_name(parent),
+ rname);
+ rname = name;
+ }
+ reg_generate_netlink_event(rname, event);
+ }
+
+ return ret;
}

int _regulator_bulk_get(struct device *dev, int num_consumers,
diff --git a/drivers/regulator/event.c b/drivers/regulator/event.c
new file mode 100644
index 000000000000..77286b419f71
--- /dev/null
+++ b/drivers/regulator/event.c
@@ -0,0 +1,86 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <regulator/regulator.h>
+#include <net/netlink.h>
+#include <net/genetlink.h>
+
+#include "regnl.h"
+
+static unsigned int reg_event_seqnum;
+
+static const struct genl_multicast_group reg_event_mcgrps[] = {
+ { .name = REG_GENL_MCAST_GROUP_NAME, },
+};
+
+static struct genl_family reg_event_genl_family __ro_after_init = {
+ .module = THIS_MODULE,
+ .name = REG_GENL_FAMILY_NAME,
+ .version = REG_GENL_VERSION,
+ .maxattr = REG_GENL_ATTR_MAX,
+ .mcgrps = reg_event_mcgrps,
+ .n_mcgrps = ARRAY_SIZE(reg_event_mcgrps),
+};
+
+int reg_generate_netlink_event(const char *reg_name, u64 event)
+{
+ struct sk_buff *skb;
+ struct nlattr *attr;
+ struct reg_genl_event *edata;
+ void *msg_header;
+ int size;
+
+ /* allocate memory */
+ size = nla_total_size(sizeof(struct reg_genl_event)) +
+ nla_total_size(0);
+
+ skb = genlmsg_new(size, GFP_ATOMIC);
+ if (!skb)
+ return -ENOMEM;
+
+ /* add the genetlink message header */
+ msg_header = genlmsg_put(skb, 0, reg_event_seqnum++,
+ &reg_event_genl_family, 0,
+ REG_GENL_CMD_EVENT);
+ if (!msg_header) {
+ nlmsg_free(skb);
+ return -ENOMEM;
+ }
+
+ /* fill the data */
+ attr = nla_reserve(skb, REG_GENL_ATTR_EVENT, sizeof(struct reg_genl_event));
+ if (!attr) {
+ nlmsg_free(skb);
+ return -EINVAL;
+ }
+
+ edata = nla_data(attr);
+ memset(edata, 0, sizeof(struct reg_genl_event));
+
+ strscpy(edata->reg_name, reg_name, sizeof(edata->reg_name));
+ edata->event = event;
+
+ /* send multicast genetlink message */
+ genlmsg_end(skb, msg_header);
+ size = genlmsg_multicast(&reg_event_genl_family, skb, 0, 0, GFP_ATOMIC);
+
+ return size;
+}
+
+static int __init reg_event_genetlink_init(void)
+{
+ return genl_register_family(&reg_event_genl_family);
+}
+
+static int __init reg_event_init(void)
+{
+ int error;
+
+ /* create genetlink for acpi event */
+ error = reg_event_genetlink_init();
+ if (error)
+ pr_warn("Failed to create genetlink family for reg event\n");
+
+ return 0;
+}
+
+fs_initcall(reg_event_init);
diff --git a/drivers/regulator/regnl.h b/drivers/regulator/regnl.h
new file mode 100644
index 000000000000..0b27972bd523
--- /dev/null
+++ b/drivers/regulator/regnl.h
@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifndef __REGULATOR_EVENT_H
+#define __REGULATOR_EVENT_H
+
+int reg_generate_netlink_event(const char *reg_name, u64 event);
+
+#endif
diff --git a/include/linux/regulator/consumer.h b/include/linux/regulator/consumer.h
index 39b666b40ea6..4660582a3302 100644
--- a/include/linux/regulator/consumer.h
+++ b/include/linux/regulator/consumer.h
@@ -33,6 +33,7 @@

#include <linux/err.h>
#include <linux/suspend.h>
+#include <regulator/regulator.h>

struct device;
struct notifier_block;
@@ -84,52 +85,6 @@ struct regulator_dev;
#define REGULATOR_MODE_IDLE 0x4
#define REGULATOR_MODE_STANDBY 0x8

-/*
- * Regulator notifier events.
- *
- * UNDER_VOLTAGE Regulator output is under voltage.
- * OVER_CURRENT Regulator output current is too high.
- * REGULATION_OUT Regulator output is out of regulation.
- * FAIL Regulator output has failed.
- * OVER_TEMP Regulator over temp.
- * FORCE_DISABLE Regulator forcibly shut down by software.
- * VOLTAGE_CHANGE Regulator voltage changed.
- * Data passed is old voltage cast to (void *).
- * DISABLE Regulator was disabled.
- * PRE_VOLTAGE_CHANGE Regulator is about to have voltage changed.
- * Data passed is "struct pre_voltage_change_data"
- * ABORT_VOLTAGE_CHANGE Regulator voltage change failed for some reason.
- * Data passed is old voltage cast to (void *).
- * PRE_DISABLE Regulator is about to be disabled
- * ABORT_DISABLE Regulator disable failed for some reason
- *
- * NOTE: These events can be OR'ed together when passed into handler.
- */
-
-#define REGULATOR_EVENT_UNDER_VOLTAGE 0x01
-#define REGULATOR_EVENT_OVER_CURRENT 0x02
-#define REGULATOR_EVENT_REGULATION_OUT 0x04
-#define REGULATOR_EVENT_FAIL 0x08
-#define REGULATOR_EVENT_OVER_TEMP 0x10
-#define REGULATOR_EVENT_FORCE_DISABLE 0x20
-#define REGULATOR_EVENT_VOLTAGE_CHANGE 0x40
-#define REGULATOR_EVENT_DISABLE 0x80
-#define REGULATOR_EVENT_PRE_VOLTAGE_CHANGE 0x100
-#define REGULATOR_EVENT_ABORT_VOLTAGE_CHANGE 0x200
-#define REGULATOR_EVENT_PRE_DISABLE 0x400
-#define REGULATOR_EVENT_ABORT_DISABLE 0x800
-#define REGULATOR_EVENT_ENABLE 0x1000
-/*
- * Following notifications should be emitted only if detected condition
- * is such that the HW is likely to still be working but consumers should
- * take a recovery action to prevent problems esacalating into errors.
- */
-#define REGULATOR_EVENT_UNDER_VOLTAGE_WARN 0x2000
-#define REGULATOR_EVENT_OVER_CURRENT_WARN 0x4000
-#define REGULATOR_EVENT_OVER_VOLTAGE_WARN 0x8000
-#define REGULATOR_EVENT_OVER_TEMP_WARN 0x10000
-#define REGULATOR_EVENT_WARN_MASK 0x1E000
-
/*
* Regulator errors that can be queried using regulator_get_error_flags
*
diff --git a/include/uapi/regulator/regulator.h b/include/uapi/regulator/regulator.h
new file mode 100644
index 000000000000..8f6b78a6fa26
--- /dev/null
+++ b/include/uapi/regulator/regulator.h
@@ -0,0 +1,85 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+
+#ifndef _UAPI_REGULATOR_H
+#define _UAPI_REGULATOR_H
+
+#ifdef __KERNEL__
+#include <linux/types.h>
+#else
+#include <stdint.h>
+#endif
+
+/*
+ * Regulator notifier events.
+ *
+ * UNDER_VOLTAGE Regulator output is under voltage.
+ * OVER_CURRENT Regulator output current is too high.
+ * REGULATION_OUT Regulator output is out of regulation.
+ * FAIL Regulator output has failed.
+ * OVER_TEMP Regulator over temp.
+ * FORCE_DISABLE Regulator forcibly shut down by software.
+ * VOLTAGE_CHANGE Regulator voltage changed.
+ * Data passed is old voltage cast to (void *).
+ * DISABLE Regulator was disabled.
+ * PRE_VOLTAGE_CHANGE Regulator is about to have voltage changed.
+ * Data passed is "struct pre_voltage_change_data"
+ * ABORT_VOLTAGE_CHANGE Regulator voltage change failed for some reason.
+ * Data passed is old voltage cast to (void *).
+ * PRE_DISABLE Regulator is about to be disabled
+ * ABORT_DISABLE Regulator disable failed for some reason
+ *
+ * NOTE: These events can be OR'ed together when passed into handler.
+ */
+
+#define REGULATOR_EVENT_UNDER_VOLTAGE 0x01
+#define REGULATOR_EVENT_OVER_CURRENT 0x02
+#define REGULATOR_EVENT_REGULATION_OUT 0x04
+#define REGULATOR_EVENT_FAIL 0x08
+#define REGULATOR_EVENT_OVER_TEMP 0x10
+#define REGULATOR_EVENT_FORCE_DISABLE 0x20
+#define REGULATOR_EVENT_VOLTAGE_CHANGE 0x40
+#define REGULATOR_EVENT_DISABLE 0x80
+#define REGULATOR_EVENT_PRE_VOLTAGE_CHANGE 0x100
+#define REGULATOR_EVENT_ABORT_VOLTAGE_CHANGE 0x200
+#define REGULATOR_EVENT_PRE_DISABLE 0x400
+#define REGULATOR_EVENT_ABORT_DISABLE 0x800
+#define REGULATOR_EVENT_ENABLE 0x1000
+/*
+ * Following notifications should be emitted only if detected condition
+ * is such that the HW is likely to still be working but consumers should
+ * take a recovery action to prevent problems esacalating into errors.
+ */
+#define REGULATOR_EVENT_UNDER_VOLTAGE_WARN 0x2000
+#define REGULATOR_EVENT_OVER_CURRENT_WARN 0x4000
+#define REGULATOR_EVENT_OVER_VOLTAGE_WARN 0x8000
+#define REGULATOR_EVENT_OVER_TEMP_WARN 0x10000
+#define REGULATOR_EVENT_WARN_MASK 0x1E000
+
+struct reg_genl_event {
+ char reg_name[32];
+ uint64_t event;
+};
+
+/* attributes of reg_genl_family */
+enum {
+ REG_GENL_ATTR_UNSPEC,
+ REG_GENL_ATTR_EVENT, /* reg event info needed by user space */
+ __REG_GENL_ATTR_MAX,
+};
+
+#define REG_GENL_ATTR_MAX (__REG_GENL_ATTR_MAX - 1)
+
+/* commands supported by the reg_genl_family */
+enum {
+ REG_GENL_CMD_UNSPEC,
+ REG_GENL_CMD_EVENT, /* kernel->user notifications for reg events */
+ __REG_GENL_CMD_MAX,
+};
+
+#define REG_GENL_CMD_MAX (__REG_GENL_CMD_MAX - 1)
+
+#define REG_GENL_FAMILY_NAME "reg_event"
+#define REG_GENL_VERSION 0x01
+#define REG_GENL_MCAST_GROUP_NAME "reg_mc_group"
+
+#endif /* _UAPI_REGULATOR_H */

base-commit: 753e4d5c433da57da75dd4c3e1aececc8e874a62
--
2.41.0