Re: [PATCH v6 06/17] dt-bindings: mfd: amd,pensando-elbasr: Add AMD Pensando Elba System Resource chip

Larson, Bradley
2022-08-31T23:01:38Z

On 8/22/22 7:25 AM, Rob Herring wrote:
> On Sat, Aug 20, 2022 at 12:57:39PM -0700, Brad Larson wrote:
>> From: Brad Larson <blarson@amd.com>
>>
>> Add support for the AMD Pensando Elba SoC System Resource chip
>> using the SPI interface. The Elba SR is a Multi-function Device
>> supporting device register access using CS0, smbus interface for
>> FRU and board peripherals using CS1, dual Lattice I2C masters for
>> transceiver management using CS2, and CS3 for flash access.
>>
>> Signed-off-by: Brad Larson <blarson@amd.com>
>> ---
>> .../bindings/mfd/amd,pensando-elbasr.yaml | 97 +++++++++++++++++++
>> 1 file changed, 97 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/mfd/amd,pensando-elbasr.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/mfd/amd,pensando-elbasr.yaml b/Documentation/devicetree/bindings/mfd/amd,pensando-elbasr.yaml
>> new file mode 100644
>> index 000000000000..ded347c3352c
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/mfd/amd,pensando-elbasr.yaml
>> @@ -0,0 +1,97 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only or BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: https://nam11.safelinks.protection.outlook.com/?url=http%3A%2F%2Fdevicetree.org%2Fschemas%2Fmfd%2Famd%2Cpensando-elbasr.yaml%23&amp;data=05%7C01%7CBradley.Larson%40amd.com%7Cd02c183f9a29492180fb08da844a3458%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637967751571358185%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=WHkA6tPbaDanQuMSaAiWUG3fBTfDVlWXMdeaO5t%2F3Ok%3D&amp;reserved=0
>> +$schema: https://nam11.safelinks.protection.outlook.com/?url=http%3A%2F%2Fdevicetree.org%2Fmeta-schemas%2Fcore.yaml%23&amp;data=05%7C01%7CBradley.Larson%40amd.com%7Cd02c183f9a29492180fb08da844a3458%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637967751571358185%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=FDig31luqeo4pOZXfuOAGiOLi0kVqFU8ExnBi5gorlY%3D&amp;reserved=0
>> +
>> +title: AMD Pensando Elba SoC Resource Controller bindings
>> +
>> +description: |
>> + AMD Pensando Elba SoC Resource Controller is a set of
>> + miscellaneous control/status registers accessed on CS0,
>> + a designware i2c master/slave on CS1, a Lattice rd1173
>> + dual i2c master on CS2, and flash on CS3. The /dev interfaces
>> + created are /dev/pensr0.<CS>. Hardware reset of the eMMC
> /dev is a Linux thing and not relevant for the bindings.
>

Removed mention of the dev interfaces

>> + is implemented by a sub-device reset-controller which accesses
>> + a CS0 control register.
>> +
>> +maintainers:
>> + - Brad Larson <blarson@amd.com>
>> +
>> +properties:
>> + compatible:
>> + items:
>> + - enum:
>> + - amd,pensando-elbasr
>> +
>> + spi-max-frequency:
>> + description: Maximum SPI frequency of the device in Hz.
> No need for generic descriptions of common properties.

Changed to "spi-max-frequency: true" and moved to end of properties.

>> +
>> + reg:
>> + maxItems: 1
>> +
>> + '#address-cells':
>> + const: 1
>> +
>> + '#size-cells':
>> + const: 0
>> +
>> + interrupts:
>> + maxItems: 1
>> +
>> +required:
>> + - compatible
>> + - reg
>> + - spi-max-frequency
>> +
>> +patternProperties:
>> + '^reset-controller@[a-f0-9]+$':
>> + $ref: /schemas/reset/amd,pensando-elbasr-reset.yaml
>> +
>> +additionalProperties: false
>> +
>> +examples:
>> + - |
>> + #include <dt-bindings/interrupt-controller/arm-gic.h>
>> +
>> + spi {
>> + #address-cells = <1>;
>> + #size-cells = <0>;
>> + num-cs = <4>;
>> +
>> + sysc: system-controller@0 {
>> + compatible = "amd,pensando-elbasr";
>> + reg = <0>;
>> + #address-cells = <1>;
>> + #size-cells = <0>;
>> + spi-max-frequency = <12000000>;
>> +
>> + rstc: reset-controller@0 {
>> + compatible = "amd,pensando-elbasr-reset";
>> + reg = <0>;
> What does 0 represent here? A register address within 'elbasr' device?

Removed, I recall a check threw a warning or error without reg.

> Why do you need a child node for this? Are there other sub-devices and
> your binding is incomplete? Just put '#reset-cells' in the parent.

Without a reset-controller node and booting the function
__of_reset_control_get(...) fails to find a match in the list here

list_for_each_entry(r, &reset_controller_list, list) {
if (args.np == r->of_node) {
rcdev = r;
break;
}
}

where in sdhci_cdns_probe(...) this lookup fails

priv->rst_hw = devm_reset_control_get_optional_exclusive(dev,
"hw");

which results in a non-functioning mmc hardware reset.

>> + #reset-cells = <1>;
>> + };
>> + };
>> +
>> + i2c1: i2c@1 {
>> + compatible = "amd,pensando-elbasr";
> You can't reuse the same compatible to represent different things.

Changed to system-controller@1 and adjusted description above

>> + reg = <1>;
>> + spi-max-frequency = <12000000>;
>> + };
>> +
>> + i2c2: i2c@2 {
>> + compatible = "amd,pensando-elbasr";
> As this is a Lattice RD1173, I would expect a compatible based on that.
>

Same as above, changed this to system-controller@2

>> + reg = <2>;
>> + spi-max-frequency = <12000000>;
>> + interrupt-parent = <&porta>;
>> + interrupts = <0 IRQ_TYPE_LEVEL_LOW>;
>> + };
>> +
>> + flash@3 {
>> + compatible = "amd,pensando-elbasr";
> Isn't this a flash device?

A userspace utility understands how to program this internal flash.
Changed to system-controller@3

Regards,
Brad