| Message ID | 20240506-dev-mule-i2c-mux-v2-0-a91c954f65d7@cherry.de |
|---|---|
| Headers | show |
| Series | Add Mule I2C multiplexer support | expand |
On Mon, 06 May 2024 13:37:51 +0200, Farouk Bouabid wrote: > 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 core itself > where the requested register is what determines which logic is executed > (muxing logic or device logic): > > 1- The devices on the mux core 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 core 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. > > To: Wolfram Sang <wsa+renesas@sang-engineering.com> > To: Peter Rosin <peda@axentia.se> > To: Andi Shyti <andi.shyti@kernel.org> > To: Rob Herring <robh@kernel.org> > To: Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org> > To: Conor Dooley <conor+dt@kernel.org> > To: Quentin Schulz <quentin.schulz@theobroma-systems.com> > To: Heiko Stuebner <heiko@sntech.de> > To: Quentin Schulz <quentin.schulz@cherry.de> > Cc: linux-i2c@vger.kernel.org > Cc: linux-kernel@vger.kernel.org > Cc: devicetree@vger.kernel.org > Cc: linux-arm-kernel@lists.infradead.org > Cc: linux-rockchip@lists.infradead.org > Signed-off-by: Farouk Bouabid <farouk.bouabid@cherry.de> > > 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@theobroma-systems.com > > --- > Farouk Bouabid (7): > i2c: mux: add the ability to share mux core 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 | 25 +++- > 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, 361 insertions(+), 12 deletions(-) > --- > base-commit: 23918f4e52d072b96a4d909e91298b8dd6ad4325 > change-id: 20240404-dev-mule-i2c-mux-9103cde07021 > > Best regards, > -- > Farouk Bouabid <farouk.bouabid@cherry.de> > > > My bot found new DTB warnings on the .dts files added or changed in this series. Some warnings may be from an existing SoC .dtsi. Or perhaps the warnings are fixed by another series. Ultimately, it is up to the platform maintainer whether these warnings are acceptable or not. No need to reply unless the platform maintainer has comments. If you already ran DT checks and didn't see these error(s), then make sure dt-schema is up to date: pip3 install dtschema --upgrade New warnings running 'make CHECK_DTBS=y rockchip/rk3588-jaguar.dtb' for 20240506-dev-mule-i2c-mux-v2-0-a91c954f65d7@cherry.de: arch/arm64/boot/dts/rockchip/rk3588-jaguar.dtb: fan@18: '#cooling-cells' does not match any of the regexes: 'pinctrl-[0-9]+' from schema $id: http://devicetree.org/schemas/trivial-devices.yaml#
Hi Peter, On 5/6/24 11:26 PM, Peter Rosin wrote: > Hi! > > Regarding the subject (and elsewhere) I think of "mux core" as roughly > the code in the i2c-mux.c file. So, for me, the "mux core" does not have > an address, it is a mux "driver instance" or "device" that sits on the > I2C address that you need to share. > I'm the one who suggested mux core here (privately) :) The issue is that in my head a mux device is the i2c adapter/bus (from i2c-mux.yaml dt binding example): """ i2c { #address-cells = <1>; #size-cells = <0>; i2c-mux@70 { compatible = "nxp,pca9548"; reg = <0x70>; #address-cells = <1>; #size-cells = <0>; i2c@3 { #address-cells = <1>; #size-cells = <0>; reg = <3>; gpio@20 { compatible = "nxp,pca9555"; gpio-controller; #gpio-cells = <2>; reg = <0x20>; }; }; i2c@4 { #address-cells = <1>; #size-cells = <0>; reg = <4>; gpio@20 { compatible = "nxp,pca9555"; gpio-controller; #gpio-cells = <2>; reg = <0x20>; }; }; }; }; """ "mux core" here would refer to i2c-mux@70, "mux device"/"mux" i2c@3 or i2c@4. E.g. when I'm saying "in mux 3", I'm talking about i2c@3 here. For me a driver instance is a device, so "mux driver instance" would be a "mux device". Ah... naming is hard. Anyway, up to you, I just wanted to make sure we're talking about the same thing and there's no confusion here. [...] > I also wonder if that second condition (...->type == &i2c_client_type) should > be a WARN_ON_ONCE? I don't see how the flag can be set sanely on an adapter > that is not itself an I2C client. Can it? > Agreed, good suggestion here... Though... https://lwn.net/Articles/969923/ it seems new additions of WARN_ON are now discouraged? Not looking to start a discussion here about whether WARN_ON is good or bad, merely pointing at this if it was missed somehow. >> + >> + if (!quirks) >> + return -ENOMEM; >> + >> + if (parent->quirks) >> + memcpy(quirks, parent->quirks, sizeof(*quirks)); >> + >> + quirks->flags |= I2C_AQ_SKIP_ADDR_CHECK; >> + quirks->skip_addr_in_parent = client->addr; >> + priv->adap.quirks = quirks; > > The I2C_AQ_SKIP_ADDR_CHECK flag should probably not be propagated? > Oh... you mean if we have a mux on an i2c adapter of a mux and the adapters handled by the parent mux have SKIP_ADDR set and we don't want the adapters handled by the leaf mux to have this flag as well? Is that what you meant? Cheers, Quentin
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 core itself where the requested register is what determines which logic is executed (muxing logic or device logic): 1- The devices on the mux core 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 core 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. To: Wolfram Sang <wsa+renesas@sang-engineering.com> To: Peter Rosin <peda@axentia.se> To: Andi Shyti <andi.shyti@kernel.org> To: Rob Herring <robh@kernel.org> To: Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org> To: Conor Dooley <conor+dt@kernel.org> To: Quentin Schulz <quentin.schulz@theobroma-systems.com> To: Heiko Stuebner <heiko@sntech.de> To: Quentin Schulz <quentin.schulz@cherry.de> Cc: linux-i2c@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: devicetree@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-rockchip@lists.infradead.org Signed-off-by: Farouk Bouabid <farouk.bouabid@cherry.de> 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@theobroma-systems.com --- Farouk Bouabid (7): i2c: mux: add the ability to share mux core 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 | 25 +++- 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, 361 insertions(+), 12 deletions(-) --- base-commit: 23918f4e52d072b96a4d909e91298b8dd6ad4325 change-id: 20240404-dev-mule-i2c-mux-9103cde07021 Best regards,