Add sysfs functionality to read the status and configuration.
The functions provide the number of stored timestamp events, the current
EVIN pin configuration and the enabled/disabled status.

Signed-off-by: Markus Burri <markus.burri@mt.com>
---
 .../ABI/testing/sysfs-class-rtc-tamper        |   8 ++
 drivers/rtc/rtc-rv8803.c                      | 106 ++++++++++++++++++
 2 files changed, 114 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-class-rtc-tamper b/Documentation/ABI/testing/sysfs-class-rtc-tamper
index 2fd6578a6..b3aa73c81 100644
--- a/Documentation/ABI/testing/sysfs-class-rtc-tamper
+++ b/Documentation/ABI/testing/sysfs-class-rtc-tamper
@@ -26,3 +26,11 @@ KernelVersion:	6.13
 Contact:	Markus Burri <markus.burri@mt.com>
 Description:	(WO) Attribute to trigger an internal timestamp event
 		Write a '1' to trigger an internal event and store a timestamp.
+
+What:		/sys/class/rtc/rtcX/tamper/status
+Date:		January 2025
+KernelVersion:	6.13
+Contact:	Markus Burri <markus.burri@mt.com>
+Description:	(RO) Attribute to read configuration and status for EVINx and buffer.
+		Provide the number of stored timestamp events, the current EVIN pin configuration
+		and the enabled/disabled status.
diff --git a/drivers/rtc/rtc-rv8803.c b/drivers/rtc/rtc-rv8803.c
index ca3a19162..350cd92d6 100644
--- a/drivers/rtc/rtc-rv8803.c
+++ b/drivers/rtc/rtc-rv8803.c
@@ -84,8 +84,11 @@
 
 #define RX8901_EVNT_INTF		0x47
 
+#define RX8901_BUF_OVWF			0x4F
+
 #define NO_OF_EVIN			3
 
+#define EVIN_FILTER_FACTOR		125
 #define EVIN_FILTER_MAX			40
 
 enum rv8803_type {
@@ -116,6 +119,26 @@ struct cfg_val_txt {
 	bool hide;
 };
 
+static const struct cfg_val_txt pull_resistor_txt[] = {
+	{ "no", no },
+	{ "PU/500k", pull_up_500k },
+	{ "PU/1M", pull_up_1M },
+	{ "PU/10M", pull_up_10M },
+	{ "PD/500k", pull_down_500k },
+	{ "no", 0b101, 1 },
+	{ "no", 0b110, 1 },
+	{ "no", 0b111, 1 },
+	{ NULL }
+};
+
+static const struct cfg_val_txt trigger_txt[] = {
+	{ "falling", falling_edge },
+	{ "rising", rising_edge },
+	{ "both", both_edges },
+	{ "both", 0b11, 1 },
+	{ NULL }
+};
+
 static const struct cfg_val_txt trg_status_txt[] = {
 	{ "EVIN1", BIT(5) },
 	{ "EVIN2", BIT(6) },
@@ -632,6 +655,16 @@ static int rv8803_nvram_read(void *priv, unsigned int offset,
 	return 0;
 }
 
+static char *cfg2txt(const struct cfg_val_txt *cfg, u8 value)
+{
+	do {
+		if (cfg->val == value)
+			return cfg->txt;
+	} while (++cfg && cfg->txt);
+
+	return NULL;
+}
+
 static int rv8803_ts_event_write_evin(int evin, struct rv8803_data *rv8803,
 				      enum evin_pull_resistor pullup_down,
 				      enum evin_trigger trigger, int filter)
@@ -935,14 +968,87 @@ static ssize_t trigger_store(struct device *dev, struct device_attribute *attr,
 	return count;
 }
 
+static ssize_t status_show(struct device *dev, struct device_attribute *attr,
+			   char *buf)
+{
+	int evin_en, evin_cfg, evin_flt, buf1_cfg, buf1_stat, buf_ovwf;
+	int i;
+	int offset = 0;
+	u8 ev_pullupdown[NO_OF_EVIN];
+	u8 ev_trigger[NO_OF_EVIN];
+	int ev_filter[NO_OF_EVIN];
+
+	struct i2c_client *client = to_i2c_client(dev->parent);
+	struct rv8803_data *rv8803 = dev_get_drvdata(dev->parent);
+
+	scoped_guard(mutex, &rv8803->flags_lock) {
+		evin_en = rv8803_read_reg(client, RX8901_EVIN_EN);
+		if (evin_en < 0)
+			return evin_en;
+
+		for (i = 0; i < NO_OF_EVIN; ++i) {
+			evin_cfg = rv8803_read_reg(client, evin_cfg_regs[i]);
+			evin_flt = rv8803_read_reg(client, evin_flt_regs[i]);
+			if (evin_cfg < 0 || evin_flt < 0)
+				return -EIO;
+
+			ev_pullupdown[i] = FIELD_GET(RX8901_EVENTx_CFG_PUPD, evin_cfg);
+			ev_trigger[i] = FIELD_GET(RX8901_EVENTx_CFG_POL, evin_cfg);
+			ev_filter[i] = EVIN_FILTER_FACTOR * evin_flt;
+		}
+
+		buf1_cfg = rv8803_read_reg(client, RX8901_BUF1_CFG1);
+		buf1_stat = rv8803_read_reg(client, RX8901_BUF1_STAT);
+		buf_ovwf = rv8803_read_reg(client, RX8901_BUF_OVWF);
+		if (buf1_stat < 0 || buf1_stat < 0 || buf_ovwf < 0)
+			return -EIO;
+	}
+
+	offset += sprintf(buf + offset, "Mode: %s\n\n",
+			  FIELD_GET(BIT(6), evin_en) ? "direct" : "fifo");
+	offset += sprintf(buf + offset, "Event config:\n");
+	offset += sprintf(buf + offset, "  %-13s  %-7s %-7s %-7s\n", "", "EVIN1", "EVIN2", "EVIN3");
+	offset += sprintf(buf + offset, "  %-13s  %-7ld %-7ld %-7ld\n", "Enable",
+			  FIELD_GET(BIT(0), evin_en), FIELD_GET(BIT(1), evin_en),
+			  FIELD_GET(BIT(2), evin_en));
+	offset += sprintf(buf + offset, "  %-13s  %-7ld %-7ld %-7ld\n", "Capture",
+			  FIELD_GET(BIT(3), evin_en), FIELD_GET(BIT(4), evin_en),
+			  FIELD_GET(BIT(5), evin_en));
+
+	offset += sprintf(buf + offset, "  %-13s  %-7s %-7s %-7s\n", "Pull-resistor",
+			  cfg2txt(pull_resistor_txt, ev_pullupdown[0]),
+			  cfg2txt(pull_resistor_txt, ev_pullupdown[1]),
+			  cfg2txt(pull_resistor_txt, ev_pullupdown[2]));
+	offset += sprintf(buf + offset, "  %-13s  %-7s %-7s %-7s\n", "Edge",
+			  cfg2txt(trigger_txt, ev_trigger[0]),
+			  cfg2txt(trigger_txt, ev_trigger[1]),
+			  cfg2txt(trigger_txt, ev_trigger[2]));
+	offset += sprintf(buf + offset, "  %-13s  %-7d %-7d %-7d\n\n", "Filter [ms]",
+			  ev_filter[0], ev_filter[1], ev_filter[2]);
+
+	offset += sprintf(buf + offset, "Buffer config:\n");
+	offset += sprintf(buf + offset, "  %-13s  %-10s\n", "Mode",
+			  (FIELD_GET(BIT(6), buf1_cfg) ? "overwrite" : "inhibit"));
+	offset += sprintf(buf + offset, "  %-13s  %-10s\n", "Status",
+			  (FIELD_GET(BIT(7), buf1_stat) ? "full" : "free"));
+	offset += sprintf(buf + offset,  "  %-13s  %-10ld\n", "Overrun",
+			  (FIELD_GET(BIT(4), buf_ovwf)));
+	offset += sprintf(buf + offset,  "  %-13s  %-10ld\n", "No of data",
+			  (FIELD_GET(GENMASK(5, 0), buf1_stat)));
+
+	return offset;
+}
+
 static DEVICE_ATTR_WO(enable);
 static DEVICE_ATTR_RO(read);
 static DEVICE_ATTR_WO(trigger);
+static DEVICE_ATTR_RO(status);
 
 static struct attribute *rv8803_rtc_event_attrs[] = {
 	&dev_attr_enable.attr,
 	&dev_attr_read.attr,
 	&dev_attr_trigger.attr,
+	&dev_attr_status.attr,
 	NULL
 };
 
-- 
2.39.5