[PATCH v7 1/5] i3c: Add HDR API support

Frank Li
2025-10-27T20:08:54Z

Rename struct i3c_priv_xfer to struct i3c_xfer, since private xfer in the
I3C spec refers only to SDR transfers. Ref: i3c spec ver1.2, section 3,
Technical Overview.

i3c_xfer will be used for both SDR and HDR.

Rename enum i3c_hdr_mode to i3c_xfer_mode. Previous definition need match
CCC GET_CAP1 bit position. Use 31 as SDR transfer mode.

Add i3c_device_do_xfers() with an xfer mode argument, while keeping
i3c_device_do_priv_xfers() as a wrapper that calls i3c_device_do_xfers()
with I3C_SDR for backward compatibility.

Introduce a 'cmd' field in struct i3c_xfer as an anonymous union with
'rnw', since HDR mode uses read/write commands instead of the SDR address
bit.

Add .i3c_xfers() callback for master controllers. If not implemented, fall
back to SDR with .priv_xfers(). The .priv_xfers() API can be removed once
all controllers switch to .i3c_xfers().

Add 'mode_mask' bitmask to advertise controller capability.

Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
Why not add hdr mode in struct i3c_priv_xfer because mode can't be mixed in
one i3c transfer. for example, can't send a HDR follow one SDR between
START and STOP.

i3c_priv_xfer should be treat as whole i3c transactions. If user want send
HDR follow SDR, should be call i3c_device_do_priv_xfers_mode() twice,
instead put into a big i3c_priv_xfer[n].

change in v7
- explicit set enum I3C_HDR_* to value, which spec required.
- add comments about check priv_xfers and i3c_xfers

change in v5-v6
- none

change in v4
- Rename enum i3c_hdr_mode to i3c_xfer_mode.

change in v3
- Add Depreciated comment for priv_xfers.

change in v2
- don't use 'priv_' since it is refer to sdr mode transfer in spec.
- add 'mode_mask' indicate controller's capibility.
- add helper function to check master's supported transfer mode.
---
drivers/i3c/device.c | 27 ++++++++++++++++++++-------
drivers/i3c/internals.h | 6 +++---
drivers/i3c/master.c | 20 ++++++++++++++++----
include/linux/i3c/device.h | 40 +++++++++++++++++++++++++++++-----------
include/linux/i3c/master.h | 4 ++++
5 files changed, 72 insertions(+), 25 deletions(-)

diff --git a/drivers/i3c/device.c b/drivers/i3c/device.c
index 2396545763ff853097d9f0173787e087f7a6e688..e6add862645196ad41d0c91d3d7103c877a1ef5a 100644
--- a/drivers/i3c/device.c
+++ b/drivers/i3c/device.c
@@ -15,12 +15,12 @@
#include "internals.h"

/**
- * i3c_device_do_priv_xfers() - do I3C SDR private transfers directed to a
- * specific device
+ * i3c_device_do_xfers() - do I3C transfers directed to a specific device
*
* @dev: device with which the transfers should be done
* @xfers: array of transfers
* @nxfers: number of transfers
+ * @mode: transfer mode
*
* Initiate one or several private SDR transfers with @dev.
*
@@ -33,9 +33,8 @@
* 'xfers' some time later. See I3C spec ver 1.1.1 09-Jun-2021. Section:
* 5.1.2.2.3.
*/
-int i3c_device_do_priv_xfers(struct i3c_device *dev,
- struct i3c_priv_xfer *xfers,
- int nxfers)
+int i3c_device_do_xfers(struct i3c_device *dev, struct i3c_priv_xfer *xfers,
+ int nxfers, enum i3c_xfer_mode mode)
{
int ret, i;

@@ -48,12 +47,12 @@ int i3c_device_do_priv_xfers(struct i3c_device *dev,
}

i3c_bus_normaluse_lock(dev->bus);
- ret = i3c_dev_do_priv_xfers_locked(dev->desc, xfers, nxfers);
+ ret = i3c_dev_do_xfers_locked(dev->desc, xfers, nxfers, mode);
i3c_bus_normaluse_unlock(dev->bus);

return ret;
}
-EXPORT_SYMBOL_GPL(i3c_device_do_priv_xfers);
+EXPORT_SYMBOL_GPL(i3c_device_do_xfers);

/**
* i3c_device_do_setdasa() - do I3C dynamic address assignement with
@@ -260,6 +259,20 @@ i3c_device_match_id(struct i3c_device *i3cdev,
}
EXPORT_SYMBOL_GPL(i3c_device_match_id);

+/**
+ * i3c_device_get_supported_xfer_mode - Returns the supported transfer mode by
+ * connected master controller.
+ * @dev: I3C device
+ *
+ * Return: a bit mask, which supported transfer mode, bit position is defined at
+ * enum i3c_hdr_mode
+ */
+u32 i3c_device_get_supported_xfer_mode(struct i3c_device *dev)
+{
+ return i3c_dev_get_master(dev->desc)->this->info.hdr_cap | BIT(I3C_SDR);
+}
+EXPORT_SYMBOL_GPL(i3c_device_get_supported_xfer_mode);
+
/**
* i3c_driver_register_with_owner() - register an I3C device driver
*
diff --git a/drivers/i3c/internals.h b/drivers/i3c/internals.h
index 79ceaa5f5afd6f8772db114472cfad99d4dd4341..f609e5098137c1b00db1830a176bb44c2802eb6f 100644
--- a/drivers/i3c/internals.h
+++ b/drivers/i3c/internals.h
@@ -15,9 +15,9 @@ void i3c_bus_normaluse_lock(struct i3c_bus *bus);
void i3c_bus_normaluse_unlock(struct i3c_bus *bus);

int i3c_dev_setdasa_locked(struct i3c_dev_desc *dev);
-int i3c_dev_do_priv_xfers_locked(struct i3c_dev_desc *dev,
- struct i3c_priv_xfer *xfers,
- int nxfers);
+int i3c_dev_do_xfers_locked(struct i3c_dev_desc *dev,
+ struct i3c_xfer *xfers,
+ int nxfers, enum i3c_xfer_mode mode);
int i3c_dev_disable_ibi_locked(struct i3c_dev_desc *dev);
int i3c_dev_enable_ibi_locked(struct i3c_dev_desc *dev);
int i3c_dev_request_ibi_locked(struct i3c_dev_desc *dev,
diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index 66513a27e6e776d251203b286bcaecb9d8fc67b9..16a480865ff4a28857f1ea6df33dbe4a66d1468c 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -2821,10 +2821,14 @@ EXPORT_SYMBOL_GPL(i3c_generic_ibi_recycle_slot);

static int i3c_master_check_ops(const struct i3c_master_controller_ops *ops)
{
- if (!ops || !ops->bus_init || !ops->priv_xfers ||
+ if (!ops || !ops->bus_init ||
!ops->send_ccc_cmd || !ops->do_daa || !ops->i2c_xfers)
return -EINVAL;

+ /* Must provide one of priv_xfers (SDR only) or i3c_xfers (all modes) */
+ if (!ops->priv_xfers && !ops->i3c_xfers)
+ return -EINVAL;
+
if (ops->request_ibi &&
(!ops->enable_ibi || !ops->disable_ibi || !ops->free_ibi ||
!ops->recycle_ibi_slot))
@@ -3014,9 +3018,8 @@ int i3c_dev_setdasa_locked(struct i3c_dev_desc *dev)
dev->boardinfo->init_dyn_addr);
}

-int i3c_dev_do_priv_xfers_locked(struct i3c_dev_desc *dev,
- struct i3c_priv_xfer *xfers,
- int nxfers)
+int i3c_dev_do_xfers_locked(struct i3c_dev_desc *dev, struct i3c_xfer *xfers,
+ int nxfers, enum i3c_xfer_mode mode)
{
struct i3c_master_controller *master;

@@ -3027,9 +3030,18 @@ int i3c_dev_do_priv_xfers_locked(struct i3c_dev_desc *dev,
if (!master || !xfers)
return -EINVAL;

+ if (mode != I3C_SDR && !(master->this->info.hdr_cap & BIT(mode)))
+ return -EOPNOTSUPP;
+
+ if (master->ops->i3c_xfers)
+ return master->ops->i3c_xfers(dev, xfers, nxfers, mode);
+
if (!master->ops->priv_xfers)
return -EOPNOTSUPP;

+ if (mode != I3C_SDR)
+ return -EINVAL;
+
return master->ops->priv_xfers(dev, xfers, nxfers);
}

diff --git a/include/linux/i3c/device.h b/include/linux/i3c/device.h
index 7f136de4b73ef839fb4a1837a87b1aebbddbfe93..7f7738041f3809e538816e94f90b99e58eb806f9 100644
--- a/include/linux/i3c/device.h
+++ b/include/linux/i3c/device.h
@@ -39,20 +39,25 @@ enum i3c_error_code {
};

/**
- * enum i3c_hdr_mode - HDR mode ids
+ * enum i3c_xfer_mode - I3C xfer mode ids
* @I3C_HDR_DDR: DDR mode
* @I3C_HDR_TSP: TSP mode
* @I3C_HDR_TSL: TSL mode
+ * @I3C_SDR: SDR mode (NOT HDR mode)
*/
-enum i3c_hdr_mode {
- I3C_HDR_DDR,
- I3C_HDR_TSP,
- I3C_HDR_TSL,
+enum i3c_xfer_mode {
+ /* The below 3 value (I3C_HDR*) must match GETCAP1 Byte bit position */
+ I3C_HDR_DDR = 0,
+ I3C_HDR_TSP = 1,
+ I3C_HDR_TSL = 2,
+ /* Use for default SDR transfer mode */
+ I3C_SDR = 0x31,
};

/**
- * struct i3c_priv_xfer - I3C SDR private transfer
+ * struct i3c_xfer - I3C data transfer
* @rnw: encodes the transfer direction. true for a read, false for a write
+ * @cmd: Read/Write command in HDR mode, read: 0x80 - 0xff, write: 0x00 - 0x7f
* @len: transfer length in bytes of the transfer
* @actual_len: actual length in bytes are transferred by the controller
* @data: input/output buffer
@@ -60,8 +65,11 @@ enum i3c_hdr_mode {
* @data.out: output buffer. Must point to a DMA-able buffer
* @err: I3C error code
*/
-struct i3c_priv_xfer {
- u8 rnw;
+struct i3c_xfer {
+ union {
+ u8 rnw;
+ u8 cmd;
+ };
u16 len;
u16 actual_len;
union {
@@ -71,6 +79,9 @@ struct i3c_priv_xfer {
enum i3c_error_code err;
};

+/* keep back compatible */
+#define i3c_priv_xfer i3c_xfer
+
/**
* enum i3c_dcr - I3C DCR values
* @I3C_DCR_GENERIC_DEVICE: generic I3C device
@@ -297,9 +308,15 @@ static __always_inline void i3c_i2c_driver_unregister(struct i3c_driver *i3cdrv,
i3c_i2c_driver_unregister, \
__i2cdrv)

-int i3c_device_do_priv_xfers(struct i3c_device *dev,
- struct i3c_priv_xfer *xfers,
- int nxfers);
+int i3c_device_do_xfers(struct i3c_device *dev, struct i3c_xfer *xfers,
+ int nxfers, enum i3c_xfer_mode mode);
+
+static inline int i3c_device_do_priv_xfers(struct i3c_device *dev,
+ struct i3c_priv_xfer *xfers,
+ int nxfers)
+{
+ return i3c_device_do_xfers(dev, xfers, nxfers, I3C_SDR);
+}

int i3c_device_do_setdasa(struct i3c_device *dev);

@@ -341,5 +358,6 @@ int i3c_device_request_ibi(struct i3c_device *dev,
void i3c_device_free_ibi(struct i3c_device *dev);
int i3c_device_enable_ibi(struct i3c_device *dev);
int i3c_device_disable_ibi(struct i3c_device *dev);
+u32 i3c_device_get_supported_xfer_mode(struct i3c_device *dev);

#endif /* I3C_DEV_H */
diff --git a/include/linux/i3c/master.h b/include/linux/i3c/master.h
index c52a82dd79a63436c1de6a01c11df9e295c1660e..7e22f9d2a2ca3f4ab808db50f809efd192c795cd 100644
--- a/include/linux/i3c/master.h
+++ b/include/linux/i3c/master.h
@@ -474,9 +474,13 @@ struct i3c_master_controller_ops {
const struct i3c_ccc_cmd *cmd);
int (*send_ccc_cmd)(struct i3c_master_controller *master,
struct i3c_ccc_cmd *cmd);
+ /* Depreciated, please use i3c_xfers() */
int (*priv_xfers)(struct i3c_dev_desc *dev,
struct i3c_priv_xfer *xfers,
int nxfers);
+ int (*i3c_xfers)(struct i3c_dev_desc *dev,
+ struct i3c_priv_xfer *xfers,
+ int nxfers, enum i3c_xfer_mode mode);
int (*attach_i2c_dev)(struct i2c_dev_desc *dev);
void (*detach_i2c_dev)(struct i2c_dev_desc *dev);
int (*i2c_xfers)(struct i2c_dev_desc *dev,

--
2.34.1