Mule is an mcu that emulates a set of I2C devices which are reachable
through an I2C-mux.
The emulated devices share a single I2C address with the mux itself
where the requested register is what determines which logic is executed
(muxing logic or device logic):
1- The devices on the mux can be selected (muxing functionality) by
writing the appropriate device number to an I2C config register (0xff)
that is not used by any device logic.
2- Any access to a register other than the config register will be
handled by the previously selected device.
+-------------------------------------------------------+
| Mule |
| +---------------+ |
----+-(1)->|Config register|-----+ |
| | +---------------+ | |
| | V_ |
| | | \ +--------+ |
| | | \-------->| dev #0 | |
| | | | +--------+ |
| | | M |-------->| dev #1 | |
| +-----------(2)------------->| U | +--------+ |
| | X |-------->| dev #2 | |
| | | +--------+ |
| | /-------->| dev #3 | |
| |__/ +--------+ |
+-------------------------------------------------------+
The current I2C-mux implementation does not allow the mux to use the
I2C address of a child device. As a workaround, A new I2C-adapter quirk is
introduced to skip the check for conflict between a child device and the
mux core I2C address when adding the child device.
This patch-series adds support for this multiplexer. Mule is integrated
as part of rk3399-puma, px30-ringneck, rk3588-tiger and rk3588-jaguar
boards.
Signed-off-by: Farouk Bouabid <farouk.bouabid@xxxxxxxxx>
Changes in v3:
- Change "i2c" in comments/commit-logs to "I2C"
- Fix long line-length
- Warn when "share_addr_with_children" is set and the Mux is not an I2C device
- Fix/stop propagating "I2C_AQ_SKIP_ADDR_CHECK" flag if "share_addr_with_children"
is not set.
- Fix "old_fw" variable is used to indicate the reversed meaning.
- Link to v2: https://lore.kernel.org/r/20240506-dev-mule-i2c-mux-v2-0-a91c954f65d7@xxxxxxxxx
Changes in v2:
- Add i2c-adapter quirks to skip checking for conflict between the mux core
and a child device address.
- Rename dt-binding to "tsd,mule-i2c-mux.yaml"
- Add Mule description to kconfig
- Fix indentation
- Move device table after probe
- Link to v1: https://lore.kernel.org/r/20240426-dev-mule-i2c-mux-v1-0-045a482f6ffb@xxxxxxxxxxxxxxxxxxxxx
---
Farouk Bouabid (7):
i2c: mux: add the ability to share mux address with child nodes
dt-bindings: i2c: mux: mule: add dt-bindings for mule i2c multiplexer
i2c: muxes: add support for mule i2c multiplexer
arm64: dts: rockchip: add mule i2c mux (0x18) on rk3399-puma
arm64: dts: rockchip: add mule i2c mux (0x18) on rk3588-tiger
arm64: dts: rockchip: add mule i2c mux (0x18) on px30-ringneck
arm64: dts: rockchip: add mule i2c mux (0x18) on rk3588-jaguar
.../devicetree/bindings/i2c/tsd,mule-i2c-mux.yaml | 80 +++++++++++
arch/arm64/boot/dts/rockchip/px30-ringneck.dtsi | 20 ++-
arch/arm64/boot/dts/rockchip/rk3399-puma.dtsi | 20 ++-
arch/arm64/boot/dts/rockchip/rk3588-jaguar.dts | 19 ++-
arch/arm64/boot/dts/rockchip/rk3588-tiger.dtsi | 19 ++-
drivers/i2c/i2c-core-base.c | 6 +-
drivers/i2c/i2c-mux.c | 48 ++++++-
drivers/i2c/muxes/Kconfig | 18 +++
drivers/i2c/muxes/Makefile | 1 +
drivers/i2c/muxes/i2c-mux-mule.c | 157 +++++++++++++++++++++
include/linux/i2c-mux.h | 1 +
include/linux/i2c.h | 7 +
12 files changed, 384 insertions(+), 12 deletions(-)
---
base-commit: 79c1f584335af42ce359ee3ff0f4e9cc324296ed
change-id: 20240404-dev-mule-i2c-mux-9103cde07021
Best regards,
--
Farouk Bouabid <farouk.bouabid@xxxxxxxxx>
