[PATCH v2 0/3] Add helper methods i3c_writel_fifo() and i3c_readl_fifo()

From: Jorge Marques
Date: Sun Jun 22 2025 - 05:21:46 EST


The i3c abstraction excepts u8 buffers, but some controllers have a bus
width of 32-bits and don't support flagging valid bytes, so it is
required to read/write long words and to use memcpy on the remainder of
the number of bytes by 32-bits to not write/read outside the buffer
bounds.

Add two auxiliary methods to include/linux/i3c/master.h and use in the dw
and cdns i3c controller drivers. The adi controller driver will also use
these methods.

Related thread: https://lore.kernel.org/linux-i3c/aFNziEj7j31xy%2FmY@lizhi-Precision-Tower-5810/

Signed-off-by: Jorge Marques <jorge.marques@xxxxxxxxxx>
---
Changes in v2:
- Rename to i3c_readl_fifo() and i3c_writel_fifo()
- Change type u8 *bytes to void *bytes
- Move methods to internals.h
- Reword commit messages to include new names and ().
- Fixup dw read fifo address (master -> master->reg)
- Link to v1: https://lore.kernel.org/r/20250620-i3c-writesl-readsl-v1-0-e0aa1c014dff@xxxxxxxxxx

---
Jorge Marques (3):
i3c: master: Add inline i3c_readl_fifo() and i3c_writel_fifo()
i3c: master: cdns: Use i3c_master_writesl() and i3c_master_readsl()
i3c: master: dw: Use i3c_master_writesl() and i3c_master_readsl()

drivers/i3c/internals.h | 37 ++++++++++++++++++++++++++++++++++++
drivers/i3c/master/dw-i3c-master.c | 25 ++++--------------------
drivers/i3c/master/i3c-master-cdns.c | 25 +++++-------------------
3 files changed, 46 insertions(+), 41 deletions(-)
---
base-commit: 51963783b876a2f493a3eac0ea9eba271cb6809a
change-id: 20250620-i3c-writesl-readsl-e2836534b665

Best regards,
--
Jorge Marques <jorge.marques@xxxxxxxxxx>