Add sysfs interface to enable the EVINx pins and read the time-stamp
events from EVINX.
Signed-off-by: Markus Burri <markus.burri@xxxxxx>
---
.../ABI/testing/sysfs-class-rtc-tamper | 21 +
drivers/rtc/rtc-rv8803.c | 366 ++++++++++++++++++
2 files changed, 387 insertions(+)
create mode 100644 Documentation/ABI/testing/sysfs-class-rtc-tamper
diff --git a/Documentation/ABI/testing/sysfs-class-rtc-tamper b/Documentation/ABI/testing/sysfs-class-rtc-tamper
new file mode 100644
index 000000000..f035d0fa5
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-rtc-tamper
@@ -0,0 +1,21 @@
+What: /sys/class/rtc/rtcX/tamper/enable
+Date: January 2025
+KernelVersion: 6.13
+Contact: Markus Burri <markus.burri@xxxxxx>
+Description: (WO) Attribute to enable and disable the rtc tamper function.
+ Write a '1' to enable tamper detection or a '0' to disable.
+
+What: /sys/class/rtc/rtcX/tamper/read
+Date: January 2025
+KernelVersion: 6.13
+Contact: Markus Burri <markus.burri@xxxxxx>
+Description: (RO) Attribute to read the stored timestamps form buffer FIFO.
+ The timestamps are returned one by one
+ Format is 'seconds.milliseconds' since the epoch followed by the trigger events.
+ The value of the event is the current pin value.
+
+ Example values:
+ - "1234.567 EVIN1=1" for a trigger from EVIN1 changed from low to high
+ - "1234.567 EVIN1=0 EVIN2=1 for a simultaneous trigger of EVIN1 changed to low and
+ EVIN2 changed to high.
+
diff --git a/drivers/rtc/rtc-rv8803.c b/drivers/rtc/rtc-rv8803.c
index 50fbae931..764e654c2 100644
--- a/drivers/rtc/rtc-rv8803.c
+++ b/drivers/rtc/rtc-rv8803.c
@@ -10,6 +10,7 @@
#include <linux/bcd.h>
#include <linux/bitops.h>
#include <linux/bitfield.h>
+#include <linux/delay.h>
#include <linux/log2.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
@@ -58,6 +59,35 @@
#define RX8900_FLAG_SWOFF BIT(2)
#define RX8900_FLAG_VDETOFF BIT(3)
+#define RX8901_EVIN_EN 0x20
+#define RX8901_EVIN1_CFG 0x21
+#define RX8901_EVIN2_CFG 0x23
+#define RX8901_EVIN3_CFG 0x25
+#define RX8901_EVENTx_CFG_POL GENMASK(1, 0)
+#define RX8901_EVENTx_CFG_PUPD GENMASK(4, 2)
+
+#define RX8901_EVIN1_FLT 0x22
+#define RX8901_EVIN2_FLT 0x24
+#define RX8901_EVIN3_FLT 0x26
+
+#define RX8901_BUF1_CFG1 0x27
+
+#define RX8901_BUF1_STAT 0x28
+#define RX8901_BUFx_STAT_PTR GENMASK(5, 0)
+#define RX8901_WRCMD_CFG 0x41
+#define RX8901_WRCMD_TRG 0x42
+
+#define RX8901_EVNT_INTE 0x43
+
+#define RX8901_BUF_INTF 0x46
+#define RX8901_BUF_INTF_BUF1F BIT(5)
+
+#define RX8901_EVNT_INTF 0x47
+
+#define NO_OF_EVIN 3
+
+#define EVIN_FILTER_MAX 40
+
enum rv8803_type {
rv_8803,
rx_8803,
@@ -66,6 +96,50 @@ enum rv8803_type {
rx_8901,
};
+enum evin_pull_resistor {
+ no = 0b000,
+ pull_up_500k = 0b001,
+ pull_up_1M = 0b010,
+ pull_up_10M = 0b011,
+ pull_down_500k = 0b100,
+};
+
+enum evin_trigger {
+ falling_edge = 0b00,
+ rising_edge = 0b01,
+ both_edges = 0b10,
+};
+
+struct cfg_val_txt {
+ char *txt;
+ u8 val;
+ bool hide;
+};
+
+static const struct cfg_val_txt trg_status_txt[] = {
+ { "EVIN1", BIT(5) },
+ { "EVIN2", BIT(6) },
+ { "EVIN3", BIT(7) },
+ { "CMD", BIT(4) },
+ { "VBATL", BIT(3) },
+ { "VTMPL", BIT(2) },
+ { "VDDL", BIT(1) },
+ { "OSCSTP", BIT(0) },
+ { NULL }
+};
+
+static const u8 evin_cfg_regs[] = {
+ RX8901_EVIN1_CFG,
+ RX8901_EVIN2_CFG,
+ RX8901_EVIN3_CFG
+};
+
+static const u8 evin_flt_regs[] = {
+ RX8901_EVIN1_FLT,
+ RX8901_EVIN2_FLT,
+ RX8901_EVIN3_FLT
+};
+
struct rv8803_data {
struct i2c_client *client;
struct rtc_device *rtc;
@@ -558,6 +632,292 @@ static int rv8803_nvram_read(void *priv, unsigned int offset,
return 0;
}
+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)
+{
+ int ret;
+ u8 reg_mask;
+ struct i2c_client *client = rv8803->client;
+
+ /* according to data-sheet, "1" is not valid for filter */
+ if (evin >= NO_OF_EVIN || filter == 1 || filter > EVIN_FILTER_MAX)
+ return -EINVAL;
+
+ guard(mutex)(&rv8803->flags_lock);
+
+ /* set EVENTx pull-up edge trigger */
+ ret = rv8803_read_reg(client, evin_cfg_regs[evin]);
+ if (ret < 0)
+ return ret;
+ reg_mask = ret;
+ reg_mask &= ~(RX8901_EVENTx_CFG_PUPD | RX8901_EVENTx_CFG_POL);
+ reg_mask |= FIELD_PREP(RX8901_EVENTx_CFG_PUPD, pullup_down);
+ reg_mask |= FIELD_PREP(RX8901_EVENTx_CFG_POL, trigger);
+ ret = rv8803_write_reg(client, evin_cfg_regs[evin], reg_mask);
+ if (ret < 0)
+ return ret;
+
+ /* set EVENTx noise filter */
+ if (filter != -1) {
+ ret = rv8803_write_reg(client, evin_flt_regs[evin], filter);
+ if (ret < 0)
+ return ret;
+ }
+
+ return 0;
+}
+
+static int rv8803_ts_enable_events(struct rv8803_data *rv8803, u8 enable_mask)
+{
+ int ret;
+ u8 reg_mask;
+ struct i2c_client *client = rv8803->client;
+
+ guard(mutex)(&rv8803->flags_lock);
+
+ /* event detection interrupt */
+ ret = rv8803_read_reg(client, RV8803_CTRL);
+ if (ret < 0)
+ return ret;
+
+ reg_mask = ret & ~RV8803_CTRL_EIE;
+ if (enable_mask)
+ reg_mask |= RV8803_CTRL_EIE;
+
+ ret = rv8803_write_reg(client, RV8803_CTRL, reg_mask);
+ if (ret)
+ return ret;
+
+ /* events for configuration */
+ ret = rv8803_write_reg(client, RX8901_EVIN_EN, enable_mask);
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
+
+static ssize_t enable_store(struct device *dev, struct device_attribute *attr, const char *buf,
+ size_t count)
+{
+ int ret;
+ int i;
+ unsigned long tmo;
+ u8 reg;
+ u8 reg_mask;
+ struct rv8803_data *rv8803 = dev_get_drvdata(dev->parent);
+ struct i2c_client *client = rv8803->client;
+
+ /* EVINxCPEN | EVINxEN */;
+ const u8 reg_mask_evin_en = GENMASK(5, 3) | GENMASK(2, 0);
+
+ bool enable = (strstr(buf, "1") == buf) ? true : false;
+
+ /* check if event detection status match requested mode */
+ ret = rv8803_read_reg(client, RX8901_EVIN_EN);
+ if (ret < 0)
+ return ret;
+
+ /* requested mode match current state -> nothing to do */
+ if (ret == (enable ? reg_mask_evin_en : 0))
+ return count;
+
+ dev_info(&client->dev, "%s time-stamp event detection\n",
+ (enable) ? "configure" : "disable");
+
+ /*
+ * 1. disable event detection interrupt
+ * 2. disable events for configuration
+ */
+ ret = rv8803_ts_enable_events(rv8803, 0);
+ if (ret < 0)
+ return ret;
+
+ /* for disable no configuration is needed */
+ if (!enable)
+ return count;
+
+ /* 3. set EVENTx pull-up edge trigger and noise filter */
+ for (i = 0; i < NO_OF_EVIN; ++i) {
+ ret = rv8803_ts_event_write_evin(i, rv8803, pull_up_1M, falling_edge, 0);
+ if (ret < 0)
+ return ret;
+ }
+
+ scoped_guard(mutex, &rv8803->flags_lock) {
+ /* 4. enable EVENTx interrupt */
+ ret = rv8803_read_reg(client, RX8901_EVNT_INTE);
+ if (ret < 0)
+ return ret;
+ reg_mask = BIT(5) | BIT(6) | BIT(7); /* EVINxIEN 1-3 */
+ reg = (ret & ~reg_mask) | reg_mask;
+ ret = rv8803_write_reg(client, RX8901_EVNT_INTE, reg);
+ if (ret < 0)
+ return ret;
+ }
+
+ /*
+ * 5. set BUF1 inhibit and interrupt every 1 event
+ * NOTE: BUF2-3 are not used in FIFO-mode
+ */
+ ret = rv8803_write_reg(client, RX8901_BUF1_CFG1, 0x01);
+ if (ret < 0)
+ return ret;
+
+ /* 6. clean and init for BUFx and event counter 1-3 and trigger cmd */
+ reg = BIT(7) | GENMASK(6, 4);
+ reg |= BIT(0); /* CMDTRGEN */
+ ret = rv8803_write_reg(client, RX8901_WRCMD_CFG, reg);
+ if (ret < 0)
+ return ret;
+ ret = rv8803_write_reg(client, RX8901_WRCMD_TRG, 0xFF);
+ if (ret < 0)
+ return ret;
+ tmo = jiffies + msecs_to_jiffies(100); /* timeout 100ms */
+ do {
+ usleep_range(10, 2000);
+ ret = rv8803_read_reg(client, RX8901_WRCMD_TRG);
+ if (ret < 0)
+ return ret;
+ if (time_after(jiffies, tmo))
+ return -EBUSY;
+ } while (ret);
+
+ /*
+ * 7. enable event detection interrupt
+ * 8. / 10. enable events for configuration in FIFO mode
+ */
+ ret = rv8803_ts_enable_events(rv8803, reg_mask_evin_en);
+ if (ret < 0)
+ return ret;
+
+ return count;
+}
+
+static ssize_t read_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ int ret;
+ int ev_idx;
+ int num_events;
+ unsigned long long time_s;
+ int time_ms;
+ int offset = 0;
+ u8 reg_mask;
+ u8 data[10];
+ struct rtc_time tm;
+
+ struct i2c_client *client = to_i2c_client(dev->parent);
+ struct rv8803_data *rv8803 = dev_get_drvdata(dev->parent);
+
+ guard(mutex)(&rv8803->flags_lock);
+
+ /*
+ * For detailed description see datasheet:
+ * - Reading Time Stamp Data (FIFO mode)
+ */
+
+ /* check interrupt source is from event 1-3 */
+ ret = rv8803_read_reg(client, RX8901_EVNT_INTF);
+ if (ret < 0)
+ return ret;
+
+ /* CHECK for EVF bit */
+ if (ret & BIT(2)) {
+ /* clear EVINxF 1-3 */
+ reg_mask = BIT(5) | BIT(6) | BIT(7);
+ ret = rv8803_write_reg(client, RX8901_EVNT_INTF, ret & ~reg_mask);
+ if (ret < 0)
+ return ret;
+ }
+
+ /* check interrupt source is from event 1-3 */
+ ret = rv8803_read_reg(client, RX8901_BUF_INTF);
+ if (ret < 0)
+ return ret;
+ if (ret & RX8901_BUF_INTF_BUF1F) {
+ /* disable interrupts */
+ ret = rv8803_read_reg(client, RV8803_CTRL);
+ if (ret < 0)
+ return ret;
+ ret = rv8803_write_reg(client, RV8803_CTRL, ret & ~RV8803_CTRL_EIE);
+ if (ret < 0)
+ return ret;
+
+ /* clear interrupt flag */
+ ret = rv8803_read_reg(client, RX8901_BUF_INTF);
+ if (ret < 0)
+ return ret;
+ ret = rv8803_write_reg(client, RX8901_BUF_INTF, ret & ~RX8901_BUF_INTF_BUF1F);
+ if (ret < 0)
+ return ret;
+ }
+
+ /* test if there are events available */
+ ret = rv8803_read_reg(client, RX8901_BUF1_STAT);
+ if (ret < 0)
+ return ret;
+ num_events = ret & RX8901_BUFx_STAT_PTR;
+
+ if (num_events) {
+ ret = rv8803_read_regs(client, 0x60, ARRAY_SIZE(data), data);
+ if (ret < 0)
+ return ret;
+
+ tm.tm_sec = bcd2bin(data[2]);
+ tm.tm_min = bcd2bin(data[3]);
+ tm.tm_hour = bcd2bin(data[4]);
+ tm.tm_mday = bcd2bin(data[5]);
+ tm.tm_mon = bcd2bin(data[6]) - 1;
+ tm.tm_year = bcd2bin(data[7]) + 100;
+ tm.tm_wday = -1;
+ tm.tm_yday = -1;
+ tm.tm_isdst = -1;
+
+ ret = rtc_valid_tm(&tm);
+ if (ret)
+ return ret;
+
+ /* calculate 1/1024 -> ms */
+ time_ms = (1000 * ((data[1] << 2) | (data[0] >> 6))) / 1024;
+ time_s = rtc_tm_to_time64(&tm);
+
+ offset += snprintf(buf + offset, PAGE_SIZE - offset, "%llu.%03d", time_s, time_ms);
+ for (ev_idx = 0; trg_status_txt[ev_idx].txt; ++ev_idx)
+ if (data[9] & trg_status_txt[ev_idx].val)
+ offset += snprintf(buf + offset, PAGE_SIZE - offset, " %s=%d",
+ trg_status_txt[ev_idx].txt,
+ !!(trg_status_txt[ev_idx].val & data[8]));
+ offset += snprintf(buf + offset, PAGE_SIZE - offset, "\n");
+
+ /* according to the datasheet we have to wait for 1ms */
+ usleep_range(1000, 2000);
+ }
+
+ /* re-enable interrupts */
+ ret = rv8803_read_reg(client, RV8803_CTRL);
+ if (ret < 0)
+ return ret;
+ ret = rv8803_write_reg(client, RV8803_CTRL, ret | RV8803_CTRL_EIE);
+ if (ret < 0)
+ return ret;
+
+ return offset;
+}
+
+static DEVICE_ATTR_WO(enable);
+static DEVICE_ATTR_RO(read);
+
+static struct attribute *rv8803_rtc_event_attrs[] = {
+ &dev_attr_enable.attr,
+ &dev_attr_read.attr,
+ NULL
+};
+
+static const struct attribute_group rv8803_rtc_sysfs_event_files = {
+ .name = "tamper",
+ .attrs = rv8803_rtc_event_attrs,
+};
+
static const struct rtc_class_ops rv8803_rtc_ops = {
.read_time = rv8803_get_time,
.set_time = rv8803_set_time,
@@ -732,6 +1092,12 @@ static int rv8803_probe(struct i2c_client *client)
if (err)
return err;
+ if (rv8803->type == rx_8901) {
+ err = rtc_add_group(rv8803->rtc, &rv8803_rtc_sysfs_event_files);
+ if (err)
+ return err;
+ }
+
rv8803->rtc->ops = &rv8803_rtc_ops;
rv8803->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
rv8803->rtc->range_max = RTC_TIMESTAMP_END_2099;
--
2.39.5
