| Message ID | 20190214175725.60462-7-ray.jui@broadcom.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | iProc I2C slave mode and NIC mode | expand |
On Thu, Feb 14, 2019 at 11:58 AM Ray Jui <ray.jui@broadcom.com> wrote: > > From: Rayagonda Kokatanur <rayagonda.kokatanur@broadcom.com> > > Update iProc I2C binding document to add new compatible string > "brcm,iproc-nic-i2c". Optional property "brcm,ape-hsls-addr-mask" is > also added that allows configuration of the host view into the APE's > address for "brcm,iproc-nic-i2c" > > Signed-off-by: Rayagonda Kokatanur <rayagonda.kokatanur@broadcom.com> > Signed-off-by: Ray Jui <ray.jui@broadcom.com> > --- > Documentation/devicetree/bindings/i2c/brcm,iproc-i2c.txt | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) Reviewed-by: Rob Herring <robh@kernel.org>
> Update iProc I2C binding document to add new compatible string > "brcm,iproc-nic-i2c". Optional property "brcm,ape-hsls-addr-mask" is > also added that allows configuration of the host view into the APE's > address for "brcm,iproc-nic-i2c" I don't know the platform, but wouldn't it be more DT-like to describe the APE in DT and derive the mask from that information? Custom bindings with values which are directly poked into a register usually raise my eyebrow.
Hi Wolfram, On 3/27/2019 3:24 PM, Wolfram Sang wrote: > >> Update iProc I2C binding document to add new compatible string >> "brcm,iproc-nic-i2c". Optional property "brcm,ape-hsls-addr-mask" is >> also added that allows configuration of the host view into the APE's >> address for "brcm,iproc-nic-i2c" > > I don't know the platform, but wouldn't it be more DT-like to describe > the APE in DT and derive the mask from that information? Custom bindings > with values which are directly poked into a register usually raise my > eyebrow. > Note APE is a co-processor that is not visible from the Linux running from the host processor. "brcm,iproc-nic-i2c" here is introduced to allow the I2C port from APE to be completely owned by the host CPU, to meet the requirement of certain use cases. At the same time, the control of the I2C port from APE will be disabled. The "brcm,ape-hsls-addr-mask" defines the address translation and be programmed into some configuration registers to allow the host to directly access the I2C registers of APE. Note those configuration registers are owned by the host, and that address is not APE's address space nor the host is intending to take over the control of APE. Therefore, I think it makes way more sense to use an address mask type of DT property here. Thanks, Ray
> Note APE is a co-processor that is not visible from the Linux running > from the host processor. > > "brcm,iproc-nic-i2c" here is introduced to allow the I2C port from APE > to be completely owned by the host CPU, to meet the requirement of > certain use cases. At the same time, the control of the I2C port from > APE will be disabled. > > The "brcm,ape-hsls-addr-mask" defines the address translation and be > programmed into some configuration registers to allow the host to > directly access the I2C registers of APE. Note those configuration > registers are owned by the host, and that address is not APE's address > space nor the host is intending to take over the control of APE. > > Therefore, I think it makes way more sense to use an address mask type > of DT property here. Thanks for the explanation! Well, since Rob is already OK with it, then so am I.
diff --git a/Documentation/devicetree/bindings/i2c/brcm,iproc-i2c.txt b/Documentation/devicetree/bindings/i2c/brcm,iproc-i2c.txt index 7a32bf81bfa9..d12cc33cca6c 100644 --- a/Documentation/devicetree/bindings/i2c/brcm,iproc-i2c.txt +++ b/Documentation/devicetree/bindings/i2c/brcm,iproc-i2c.txt @@ -3,7 +3,7 @@ Broadcom iProc I2C controller Required properties: - compatible: - Must be "brcm,iproc-i2c" + Must be "brcm,iproc-i2c" or "brcm,iproc-nic-i2c" - reg: Define the base and range of the I/O address space that contain the iProc @@ -26,6 +26,10 @@ Optional properties: case, this property should be left unspecified, and driver will fall back to polling mode +- brcm,ape-hsls-addr-mask: + Required for "brcm,iproc-nic-i2c". Host view of address mask into the + 'APE' co-processor. Value must be unsigned, 32-bit + Example: i2c0: i2c@18008000 { compatible = "brcm,iproc-i2c";