Merge tag 'i3c/for-6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux

Pull i3c updates from Alexandre Belloni:
 "We are continuing to see more fixes as hardware is available and code
  is actually getting tested.

  Core:
   - Add a sysfs control for hotjoin
   - Add fallback method for GETMXDS CCC

  Drivers:
   - cdns: fix prescale for i2c clock
   - mipi-i3c-hci: more fixes now that the driver is used
   - svc: hotjoin enabling/disabling support"

* tag 'i3c/for-6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux:
  i3c: document hotjoin sysfs entry
  i3c: master: fix kernel-doc check warning
  i3c: master: cdns: Update maximum prescaler value for i2c clock
  i3c: master: fix Excess kernel-doc description warning
  i3c: master: svc: return actual transfer data len
  i3c: master: svc: rename read_len as actual_len
  i3c: add actual_len in i3c_priv_xfer
  i3c: master: svc: add hot join support
  i3c: master: add enable(disable) hot join in sys entry
  i3c: master: Fix build error
  i3c: Add fallback method for GETMXDS CCC
  i3c: mipi-i3c-hci: Add DMA bounce buffer for private transfers
  i3c: mipi-i3c-hci: Handle I3C address header error in hci_cmd_v1_daa()
  i3c: mipi-i3c-hci: Do not overallocate transfers in hci_cmd_v1_daa()
  i3c: mipi-i3c-hci: Report NACK response from CCC command to core

Documentation/ABI/testing/sysfs-bus-i3c

@@ -88,6 +88,21 @@ Description:
 		This entry describes the HDRCAP of the master controller
 		driving the bus.
 
+What:		/sys/bus/i3c/devices/i3c-<bus-id>/hotjoin
+KernelVersion:  6.8
+Contact:	linux-i3c@vger.kernel.org
+Description:
+		I3C’s Hot-Join mechanism allows an I3C Device to inform the
+		Active Controller that a newly-joined Target is present on the
+		I3C Bus and is ready to receive a Dynamic Address, in order to
+		become fully functional on the Bus. Hot-Join is used when the
+		Target is mounted on the same I3C bus and remains depowered
+		until needed or until the Target is physically inserted into the
+		I3C bus
+
+		This entry allows to enable or disable Hot-join of the Current
+		Controller driving the bus.
+
 What:		/sys/bus/i3c/devices/i3c-<bus-id>/<bus-id>-<device-pid>
 KernelVersion:  5.0
 Contact:	linux-i3c@vger.kernel.org

drivers/i3c/master.c

@@ -557,6 +557,88 @@ static ssize_t i2c_scl_frequency_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(i2c_scl_frequency);
 
+static int i3c_set_hotjoin(struct i3c_master_controller *master, bool enable)
+{
+	int ret;
+
+	if (!master || !master->ops)
+		return -EINVAL;
+
+	if (!master->ops->enable_hotjoin || !master->ops->disable_hotjoin)
+		return -EINVAL;
+
+	i3c_bus_normaluse_lock(&master->bus);
+
+	if (enable)
+		ret = master->ops->enable_hotjoin(master);
+	else
+		ret = master->ops->disable_hotjoin(master);
+
+	master->hotjoin = enable;
+
+	i3c_bus_normaluse_unlock(&master->bus);
+
+	return ret;
+}
+
+static ssize_t hotjoin_store(struct device *dev, struct device_attribute *attr,
+			     const char *buf, size_t count)
+{
+	struct i3c_bus *i3cbus = dev_to_i3cbus(dev);
+	int ret;
+	bool res;
+
+	if (!i3cbus->cur_master)
+		return -EINVAL;
+
+	if (kstrtobool(buf, &res))
+		return -EINVAL;
+
+	ret = i3c_set_hotjoin(i3cbus->cur_master->common.master, res);
+	if (ret)
+		return ret;
+
+	return count;
+}
+
+/*
+ * i3c_master_enable_hotjoin - Enable hotjoin
+ * @master: I3C master object
+ *
+ * Return: a 0 in case of success, an negative error code otherwise.
+ */
+int i3c_master_enable_hotjoin(struct i3c_master_controller *master)
+{
+	return i3c_set_hotjoin(master, true);
+}
+EXPORT_SYMBOL_GPL(i3c_master_enable_hotjoin);
+
+/*
+ * i3c_master_disable_hotjoin - Disable hotjoin
+ * @master: I3C master object
+ *
+ * Return: a 0 in case of success, an negative error code otherwise.
+ */
+int i3c_master_disable_hotjoin(struct i3c_master_controller *master)
+{
+	return i3c_set_hotjoin(master, false);
+}
+EXPORT_SYMBOL_GPL(i3c_master_disable_hotjoin);
+
+static ssize_t hotjoin_show(struct device *dev, struct device_attribute *da, char *buf)
+{
+	struct i3c_bus *i3cbus = dev_to_i3cbus(dev);
+	ssize_t ret;
+
+	i3c_bus_normaluse_lock(i3cbus);
+	ret = sysfs_emit(buf, "%d\n", i3cbus->cur_master->common.master->hotjoin);
+	i3c_bus_normaluse_unlock(i3cbus);
+
+	return ret;
+}
+
+static DEVICE_ATTR_RW(hotjoin);
+
 static struct attribute *i3c_masterdev_attrs[] = {
 	&dev_attr_mode.attr,
 	&dev_attr_current_master.attr,
@@ -567,6 +649,7 @@ static struct attribute *i3c_masterdev_attrs[] = {
 	&dev_attr_pid.attr,
 	&dev_attr_dynamic_address.attr,
 	&dev_attr_hdrcap.attr,
+	&dev_attr_hotjoin.attr,
 	NULL,
 };
 ATTRIBUTE_GROUPS(i3c_masterdev);
@@ -1130,8 +1213,16 @@ static int i3c_master_getmxds_locked(struct i3c_master_controller *master,
 
 	i3c_ccc_cmd_init(&cmd, true, I3C_CCC_GETMXDS, &dest, 1);
 	ret = i3c_master_send_ccc_cmd_locked(master, &cmd);
-	if (ret)
-		goto out;
+	if (ret) {
+		/*
+		 * Retry when the device does not support max read turnaround
+		 * while expecting shorter length from this CCC command.
+		 */
+		dest.payload.len -= 3;
+		ret = i3c_master_send_ccc_cmd_locked(master, &cmd);
+		if (ret)
+			goto out;
+	}
 
 	if (dest.payload.len != 2 && dest.payload.len != 5) {
 		ret = -EIO;

drivers/i3c/master/i3c-master-cdns.c

@@ -76,7 +76,8 @@
 #define PRESCL_CTRL0			0x14
 #define PRESCL_CTRL0_I2C(x)		((x) << 16)
 #define PRESCL_CTRL0_I3C(x)		(x)
-#define PRESCL_CTRL0_MAX		GENMASK(9, 0)
+#define PRESCL_CTRL0_I3C_MAX		GENMASK(9, 0)
+#define PRESCL_CTRL0_I2C_MAX		GENMASK(15, 0)
 
 #define PRESCL_CTRL1			0x18
 #define PRESCL_CTRL1_PP_LOW_MASK	GENMASK(15, 8)
@@ -1233,7 +1234,7 @@ static int cdns_i3c_master_bus_init(struct i3c_master_controller *m)
 		return -EINVAL;
 
 	pres = DIV_ROUND_UP(sysclk_rate, (bus->scl_rate.i3c * 4)) - 1;
-	if (pres > PRESCL_CTRL0_MAX)
+	if (pres > PRESCL_CTRL0_I3C_MAX)
 		return -ERANGE;
 
 	bus->scl_rate.i3c = sysclk_rate / ((pres + 1) * 4);
@@ -1246,7 +1247,7 @@ static int cdns_i3c_master_bus_init(struct i3c_master_controller *m)
 	max_i2cfreq = bus->scl_rate.i2c;
 
 	pres = (sysclk_rate / (max_i2cfreq * 5)) - 1;
-	if (pres > PRESCL_CTRL0_MAX)
+	if (pres > PRESCL_CTRL0_I2C_MAX)
 		return -ERANGE;
 
 	bus->scl_rate.i2c = sysclk_rate / ((pres + 1) * 5);

drivers/i3c/master/mipi-i3c-hci/cmd_v1.c

@@ -298,7 +298,7 @@ static int hci_cmd_v1_daa(struct i3c_hci *hci)
 	unsigned int dcr, bcr;
 	DECLARE_COMPLETION_ONSTACK(done);
 
-	xfer = hci_alloc_xfer(2);
+	xfer = hci_alloc_xfer(1);
 	if (!xfer)
 		return -ENOMEM;
 
@@ -339,12 +339,13 @@ static int hci_cmd_v1_daa(struct i3c_hci *hci)
 			ret = -ETIME;
 			break;
 		}
-		if (RESP_STATUS(xfer[0].response) == RESP_ERR_NACK &&
+		if ((RESP_STATUS(xfer->response) == RESP_ERR_ADDR_HEADER ||
+		     RESP_STATUS(xfer->response) == RESP_ERR_NACK) &&
 		    RESP_DATA_LENGTH(xfer->response) == 1) {
 			ret = 0;  /* no more devices to be assigned */
 			break;
 		}
-		if (RESP_STATUS(xfer[0].response) != RESP_SUCCESS) {
+		if (RESP_STATUS(xfer->response) != RESP_SUCCESS) {
 			ret = -EIO;
 			break;
 		}

drivers/i3c/master/mipi-i3c-hci/core.c

@@ -245,7 +245,14 @@ static int i3c_hci_send_ccc_cmd(struct i3c_master_controller *m,
 		if (ccc->rnw)
 			ccc->dests[i - prefixed].payload.len =
 				RESP_DATA_LENGTH(xfer[i].response);
-		if (RESP_STATUS(xfer[i].response) != RESP_SUCCESS) {
+		switch (RESP_STATUS(xfer[i].response)) {
+		case RESP_SUCCESS:
+			continue;
+		case RESP_ERR_ADDR_HEADER:
+		case RESP_ERR_NACK:
+			ccc->err = I3C_ERROR_M2;
+			fallthrough;
+		default:
 			ret = -EIO;
 			goto out;
 		}
@@ -269,6 +276,34 @@ static int i3c_hci_daa(struct i3c_master_controller *m)
 	return hci->cmd->perform_daa(hci);
 }
 
+static int i3c_hci_alloc_safe_xfer_buf(struct i3c_hci *hci,
+				       struct hci_xfer *xfer)
+{
+	if (hci->io != &mipi_i3c_hci_dma ||
+	    xfer->data == NULL || !is_vmalloc_addr(xfer->data))
+		return 0;
+
+	if (xfer->rnw)
+		xfer->bounce_buf = kzalloc(xfer->data_len, GFP_KERNEL);
+	else
+		xfer->bounce_buf = kmemdup(xfer->data,
+					   xfer->data_len, GFP_KERNEL);
+
+	return xfer->bounce_buf == NULL ? -ENOMEM : 0;
+}
+
+static void i3c_hci_free_safe_xfer_buf(struct i3c_hci *hci,
+				       struct hci_xfer *xfer)
+{
+	if (hci->io != &mipi_i3c_hci_dma || xfer->bounce_buf == NULL)
+		return;
+
+	if (xfer->rnw)
+		memcpy(xfer->data, xfer->bounce_buf, xfer->data_len);
+
+	kfree(xfer->bounce_buf);
+}
+
 static int i3c_hci_priv_xfers(struct i3c_dev_desc *dev,
 			      struct i3c_priv_xfer *i3c_xfers,
 			      int nxfers)
@@ -302,6 +337,9 @@ static int i3c_hci_priv_xfers(struct i3c_dev_desc *dev,
 		}
 		hci->cmd->prep_i3c_xfer(hci, dev, &xfer[i]);
 		xfer[i].cmd_desc[0] |= CMD_0_ROC;
+		ret = i3c_hci_alloc_safe_xfer_buf(hci, &xfer[i]);
+		if (ret)
+			goto out;
 	}
 	last = i - 1;
 	xfer[last].cmd_desc[0] |= CMD_0_TOC;
@@ -325,6 +363,9 @@ static int i3c_hci_priv_xfers(struct i3c_dev_desc *dev,
 	}
 
 out:
+	for (i = 0; i < nxfers; i++)
+		i3c_hci_free_safe_xfer_buf(hci, &xfer[i]);
+
 	hci_free_xfer(xfer, nxfers);
 	return ret;
 }
@@ -350,6 +391,9 @@ static int i3c_hci_i2c_xfers(struct i2c_dev_desc *dev,
 		xfer[i].rnw = i2c_xfers[i].flags & I2C_M_RD;
 		hci->cmd->prep_i2c_xfer(hci, dev, &xfer[i]);
 		xfer[i].cmd_desc[0] |= CMD_0_ROC;
+		ret = i3c_hci_alloc_safe_xfer_buf(hci, &xfer[i]);
+		if (ret)
+			goto out;
 	}
 	last = i - 1;
 	xfer[last].cmd_desc[0] |= CMD_0_TOC;
@@ -371,6 +415,9 @@ static int i3c_hci_i2c_xfers(struct i2c_dev_desc *dev,
 	}
 
 out:
+	for (i = 0; i < nxfers; i++)
+		i3c_hci_free_safe_xfer_buf(hci, &xfer[i]);
+
 	hci_free_xfer(xfer, nxfers);
 	return ret;
 }

drivers/i3c/master/mipi-i3c-hci/dma.c

@@ -362,6 +362,7 @@ static int hci_dma_queue_xfer(struct i3c_hci *hci,
 	struct hci_rh_data *rh;
 	unsigned int i, ring, enqueue_ptr;
 	u32 op1_val, op2_val;
+	void *buf;
 
 	/* For now we only use ring 0 */
 	ring = 0;
@@ -390,9 +391,10 @@ static int hci_dma_queue_xfer(struct i3c_hci *hci,
 
 		/* 2nd and 3rd words of Data Buffer Descriptor Structure */
 		if (xfer->data) {
+			buf = xfer->bounce_buf ? xfer->bounce_buf : xfer->data;
 			xfer->data_dma =
 				dma_map_single(&hci->master.dev,
-					       xfer->data,
+					       buf,
 					       xfer->data_len,
 					       xfer->rnw ?
 						  DMA_FROM_DEVICE :

drivers/i3c/master/mipi-i3c-hci/hci.h

@@ -90,6 +90,7 @@ struct hci_xfer {
 		struct {
 			/* DMA specific */
 			dma_addr_t data_dma;
+			void *bounce_buf;
 			int ring_number;
 			int ring_entry;
 		};

drivers/i3c/master/svc-i3c-master.c

@@ -128,13 +128,17 @@
 /* This parameter depends on the implementation and may be tuned */
 #define SVC_I3C_FIFO_SIZE 16
 
+#define SVC_I3C_EVENT_IBI	BIT(0)
+#define SVC_I3C_EVENT_HOTJOIN	BIT(1)
+
 struct svc_i3c_cmd {
 	u8 addr;
 	bool rnw;
 	u8 *in;
 	const void *out;
 	unsigned int len;
-	unsigned int read_len;
+	unsigned int actual_len;
+	struct i3c_priv_xfer *xfer;
 	bool continued;
 };
 
@@ -177,6 +181,7 @@ struct svc_i3c_regs_save {
  * @ibi.tbq_slot: To be queued IBI slot
  * @ibi.lock: IBI lock
  * @lock: Transfer lock, protect between IBI work thread and callbacks from master
+ * @enabled_events: Bit masks for enable events (IBI, HotJoin).
  */
 struct svc_i3c_master {
 	struct i3c_master_controller base;
@@ -206,6 +211,7 @@ struct svc_i3c_master {
 		spinlock_t lock;
 	} ibi;
 	struct mutex lock;
+	int enabled_events;
 };
 
 /**
@@ -220,6 +226,11 @@ struct svc_i3c_i2c_dev_data {
 	struct i3c_generic_ibi_pool *ibi_pool;
 };
 
+static inline bool is_events_enabled(struct svc_i3c_master *master, u32 mask)
+{
+	return !!(master->enabled_events & mask);
+}
+
 static bool svc_i3c_master_error(struct svc_i3c_master *master)
 {
 	u32 mstatus, merrwarn;
@@ -429,13 +440,16 @@ static void svc_i3c_master_ibi_work(struct work_struct *work)
 	switch (ibitype) {
 	case SVC_I3C_MSTATUS_IBITYPE_IBI:
 		dev = svc_i3c_master_dev_from_addr(master, ibiaddr);
-		if (!dev)
+		if (!dev || !is_events_enabled(master, SVC_I3C_EVENT_IBI))
 			svc_i3c_master_nack_ibi(master);
 		else
 			svc_i3c_master_handle_ibi(master, dev);
 		break;
 	case SVC_I3C_MSTATUS_IBITYPE_HOT_JOIN:
-		svc_i3c_master_ack_ibi(master, false);
+		if (is_events_enabled(master, SVC_I3C_EVENT_HOTJOIN))
+			svc_i3c_master_ack_ibi(master, false);
+		else
+			svc_i3c_master_nack_ibi(master);
 		break;
 	case SVC_I3C_MSTATUS_IBITYPE_MASTER_REQUEST:
 		svc_i3c_master_nack_ibi(master);
@@ -472,7 +486,9 @@ static void svc_i3c_master_ibi_work(struct work_struct *work)
 		svc_i3c_master_emit_stop(master);
 		break;
 	case SVC_I3C_MSTATUS_IBITYPE_HOT_JOIN:
-		queue_work(master->base.wq, &master->hj_work);
+		svc_i3c_master_emit_stop(master);
+		if (is_events_enabled(master, SVC_I3C_EVENT_HOTJOIN))
+			queue_work(master->base.wq, &master->hj_work);
 		break;
 	case SVC_I3C_MSTATUS_IBITYPE_MASTER_REQUEST:
 	default:
@@ -1024,7 +1040,7 @@ static int svc_i3c_master_write(struct svc_i3c_master *master,
 static int svc_i3c_master_xfer(struct svc_i3c_master *master,
 			       bool rnw, unsigned int xfer_type, u8 addr,
 			       u8 *in, const u8 *out, unsigned int xfer_len,
-			       unsigned int *read_len, bool continued)
+			       unsigned int *actual_len, bool continued)
 {
 	u32 reg;
 	int ret;
@@ -1037,7 +1053,7 @@ static int svc_i3c_master_xfer(struct svc_i3c_master *master,
 	       SVC_I3C_MCTRL_IBIRESP_NACK |
 	       SVC_I3C_MCTRL_DIR(rnw) |
 	       SVC_I3C_MCTRL_ADDR(addr) |
-	       SVC_I3C_MCTRL_RDTERM(*read_len),
+	       SVC_I3C_MCTRL_RDTERM(*actual_len),
 	       master->regs + SVC_I3C_MCTRL);
 
 	ret = readl_poll_timeout(master->regs + SVC_I3C_MSTATUS, reg,
@@ -1047,6 +1063,7 @@ static int svc_i3c_master_xfer(struct svc_i3c_master *master,
 
 	if (readl(master->regs + SVC_I3C_MERRWARN) & SVC_I3C_MERRWARN_NACK) {
 		ret = -ENXIO;
+		*actual_len = 0;
 		goto emit_stop;
 	}
 
@@ -1064,6 +1081,7 @@ static int svc_i3c_master_xfer(struct svc_i3c_master *master,
 	 */
 	if (SVC_I3C_MSTATUS_IBIWON(reg)) {
 		ret = -ENXIO;
+		*actual_len = 0;
 		goto emit_stop;
 	}
 
@@ -1075,7 +1093,7 @@ static int svc_i3c_master_xfer(struct svc_i3c_master *master,
 		goto emit_stop;
 
 	if (rnw)
-		*read_len = ret;
+		*actual_len = ret;
 
 	ret = readl_poll_timeout(master->regs + SVC_I3C_MSTATUS, reg,
 				 SVC_I3C_MSTATUS_COMPLETE(reg), 0, 1000);
@@ -1157,8 +1175,12 @@ static void svc_i3c_master_start_xfer_locked(struct svc_i3c_master *master)
 
 		ret = svc_i3c_master_xfer(master, cmd->rnw, xfer->type,
 					  cmd->addr, cmd->in, cmd->out,
-					  cmd->len, &cmd->read_len,
+					  cmd->len, &cmd->actual_len,
 					  cmd->continued);
+		/* cmd->xfer is NULL if I2C or CCC transfer */
+		if (cmd->xfer)
+			cmd->xfer->actual_len = cmd->actual_len;
+
 		if (ret)
 			break;
 	}
@@ -1243,7 +1265,7 @@ static int svc_i3c_master_send_bdcast_ccc_cmd(struct svc_i3c_master *master,
 	cmd->in = NULL;
 	cmd->out = buf;
 	cmd->len = xfer_len;
-	cmd->read_len = 0;
+	cmd->actual_len = 0;
 	cmd->continued = false;
 
 	mutex_lock(&master->lock);
@@ -1263,7 +1285,7 @@ static int svc_i3c_master_send_direct_ccc_cmd(struct svc_i3c_master *master,
 					      struct i3c_ccc_cmd *ccc)
 {
 	unsigned int xfer_len = ccc->dests[0].payload.len;
-	unsigned int read_len = ccc->rnw ? xfer_len : 0;
+	unsigned int actual_len = ccc->rnw ? xfer_len : 0;
 	struct svc_i3c_xfer *xfer;
 	struct svc_i3c_cmd *cmd;
 	int ret;
@@ -1281,7 +1303,7 @@ static int svc_i3c_master_send_direct_ccc_cmd(struct svc_i3c_master *master,
 	cmd->in = NULL;
 	cmd->out = &ccc->id;
 	cmd->len = 1;
-	cmd->read_len = 0;
+	cmd->actual_len = 0;
 	cmd->continued = true;
 
 	/* Directed message */
@@ -1291,7 +1313,7 @@ static int svc_i3c_master_send_direct_ccc_cmd(struct svc_i3c_master *master,
 	cmd->in = ccc->rnw ? ccc->dests[0].payload.data : NULL;
 	cmd->out = ccc->rnw ? NULL : ccc->dests[0].payload.data,
 	cmd->len = xfer_len;
-	cmd->read_len = read_len;
+	cmd->actual_len = actual_len;
 	cmd->continued = false;
 
 	mutex_lock(&master->lock);
@@ -1300,8 +1322,8 @@ static int svc_i3c_master_send_direct_ccc_cmd(struct svc_i3c_master *master,
 		svc_i3c_master_dequeue_xfer(master, xfer);
 	mutex_unlock(&master->lock);
 
-	if (cmd->read_len != xfer_len)
-		ccc->dests[0].payload.len = cmd->read_len;
+	if (cmd->actual_len != xfer_len)
+		ccc->dests[0].payload.len = cmd->actual_len;
 
 	ret = xfer->ret;
 	svc_i3c_master_free_xfer(xfer);
@@ -1346,12 +1368,13 @@ static int svc_i3c_master_priv_xfers(struct i3c_dev_desc *dev,
 	for (i = 0; i < nxfers; i++) {
 		struct svc_i3c_cmd *cmd = &xfer->cmds[i];
 
+		cmd->xfer = &xfers[i];
 		cmd->addr = master->addrs[data->index];
 		cmd->rnw = xfers[i].rnw;
 		cmd->in = xfers[i].rnw ? xfers[i].data.in : NULL;
 		cmd->out = xfers[i].rnw ? NULL : xfers[i].data.out;
 		cmd->len = xfers[i].len;
-		cmd->read_len = xfers[i].rnw ? xfers[i].len : 0;
+		cmd->actual_len = xfers[i].rnw ? xfers[i].len : 0;
 		cmd->continued = (i + 1) < nxfers;
 	}
 
@@ -1391,7 +1414,7 @@ static int svc_i3c_master_i2c_xfers(struct i2c_dev_desc *dev,
 		cmd->in = cmd->rnw ? xfers[i].buf : NULL;
 		cmd->out = cmd->rnw ? NULL : xfers[i].buf;
 		cmd->len = xfers[i].len;
-		cmd->read_len = cmd->rnw ? xfers[i].len : 0;
+		cmd->actual_len = cmd->rnw ? xfers[i].len : 0;
 		cmd->continued = (i + 1 < nxfers);
 	}
 
@@ -1472,6 +1495,7 @@ static int svc_i3c_master_enable_ibi(struct i3c_dev_desc *dev)
 		return ret;
 	}
 
+	master->enabled_events |= SVC_I3C_EVENT_IBI;
 	svc_i3c_master_enable_interrupts(master, SVC_I3C_MINT_SLVSTART);
 
 	return i3c_master_enec_locked(m, dev->info.dyn_addr, I3C_CCC_EVENT_SIR);
@@ -1483,7 +1507,9 @@ static int svc_i3c_master_disable_ibi(struct i3c_dev_desc *dev)
 	struct svc_i3c_master *master = to_svc_i3c_master(m);
 	int ret;
 
-	svc_i3c_master_disable_interrupts(master);
+	master->enabled_events &= ~SVC_I3C_EVENT_IBI;
+	if (!master->enabled_events)
+		svc_i3c_master_disable_interrupts(master);
 
 	ret = i3c_master_disec_locked(m, dev->info.dyn_addr, I3C_CCC_EVENT_SIR);
 
@@ -1493,6 +1519,39 @@ static int svc_i3c_master_disable_ibi(struct i3c_dev_desc *dev)
 	return ret;
 }
 
+static int svc_i3c_master_enable_hotjoin(struct i3c_master_controller *m)
+{
+	struct svc_i3c_master *master = to_svc_i3c_master(m);
+	int ret;
+
+	ret = pm_runtime_resume_and_get(master->dev);
+	if (ret < 0) {
+		dev_err(master->dev, "<%s> Cannot get runtime PM.\n", __func__);
+		return ret;
+	}
+
+	master->enabled_events |= SVC_I3C_EVENT_HOTJOIN;
+
+	svc_i3c_master_enable_interrupts(master, SVC_I3C_MINT_SLVSTART);
+
+	return 0;
+}
+
+static int svc_i3c_master_disable_hotjoin(struct i3c_master_controller *m)
+{
+	struct svc_i3c_master *master = to_svc_i3c_master(m);
+
+	master->enabled_events &= ~SVC_I3C_EVENT_HOTJOIN;
+
+	if (!master->enabled_events)
+		svc_i3c_master_disable_interrupts(master);
+
+	pm_runtime_mark_last_busy(master->dev);
+	pm_runtime_put_autosuspend(master->dev);
+
+	return 0;
+}
+
 static void svc_i3c_master_recycle_ibi_slot(struct i3c_dev_desc *dev,
 					    struct i3c_ibi_slot *slot)
 {
@@ -1519,6 +1578,8 @@ static const struct i3c_master_controller_ops svc_i3c_master_ops = {
 	.recycle_ibi_slot = svc_i3c_master_recycle_ibi_slot,
 	.enable_ibi = svc_i3c_master_enable_ibi,
 	.disable_ibi = svc_i3c_master_disable_ibi,
+	.enable_hotjoin = svc_i3c_master_enable_hotjoin,
+	.disable_hotjoin = svc_i3c_master_disable_hotjoin,
 };
 
 static int svc_i3c_master_prepare_clks(struct svc_i3c_master *master)

include/linux/i3c/device.h

@@ -54,6 +54,7 @@ enum i3c_hdr_mode {
  * struct i3c_priv_xfer - I3C SDR private transfer
  * @rnw: encodes the transfer direction. true for a read, false for a write
  * @len: transfer length in bytes of the transfer
+ * @actual_len: actual length in bytes are transferred by the controller
  * @data: input/output buffer
  * @data.in: input buffer. Must point to a DMA-able buffer
  * @data.out: output buffer. Must point to a DMA-able buffer
@@ -62,6 +63,7 @@ enum i3c_hdr_mode {
 struct i3c_priv_xfer {
 	u8 rnw;
 	u16 len;
+	u16 actual_len;
 	union {
 		void *in;
 		const void *out;

include/linux/i3c/master.h

@@ -76,7 +76,6 @@ struct i2c_dev_boardinfo {
 /**
  * struct i2c_dev_desc - I2C device descriptor
  * @common: common part of the I2C device descriptor
- * @boardinfo: pointer to the boardinfo attached to this I2C device
  * @dev: I2C device object registered to the I2C framework
  * @addr: I2C device address
  * @lvr: LVR (Legacy Virtual Register) needed by the I3C core to know about
@@ -434,6 +433,8 @@ struct i3c_bus {
  *		      for a future IBI
  *		      This method is mandatory only if ->request_ibi is not
  *		      NULL.
+ * @enable_hotjoin: enable hot join event detect.
+ * @disable_hotjoin: disable hot join event detect.
  */
 struct i3c_master_controller_ops {
 	int (*bus_init)(struct i3c_master_controller *master);
@@ -460,6 +461,8 @@ struct i3c_master_controller_ops {
 	int (*disable_ibi)(struct i3c_dev_desc *dev);
 	void (*recycle_ibi_slot)(struct i3c_dev_desc *dev,
 				 struct i3c_ibi_slot *slot);
+	int (*enable_hotjoin)(struct i3c_master_controller *master);
+	int (*disable_hotjoin)(struct i3c_master_controller *master);
 };
 
 /**
@@ -473,6 +476,7 @@ struct i3c_master_controller_ops {
  * @ops: master operations. See &struct i3c_master_controller_ops
  * @secondary: true if the master is a secondary master
  * @init_done: true when the bus initialization is done
+ * @hotjoin: true if the master support hotjoin
  * @boardinfo.i3c: list of I3C  boardinfo objects
  * @boardinfo.i2c: list of I2C boardinfo objects
  * @boardinfo: board-level information attached to devices connected on the bus
@@ -495,6 +499,7 @@ struct i3c_master_controller {
 	const struct i3c_master_controller_ops *ops;
 	unsigned int secondary : 1;
 	unsigned int init_done : 1;
+	unsigned int hotjoin: 1;
 	struct {
 		struct list_head i3c;
 		struct list_head i2c;
@@ -551,6 +556,8 @@ int i3c_master_register(struct i3c_master_controller *master,
 			const struct i3c_master_controller_ops *ops,
 			bool secondary);
 void i3c_master_unregister(struct i3c_master_controller *master);
+int i3c_master_enable_hotjoin(struct i3c_master_controller *master);
+int i3c_master_disable_hotjoin(struct i3c_master_controller *master);
 
 /**
  * i3c_dev_get_master_data() - get master private data attached to an I3C