Zephyr Cadence IIC Driver Support

This page gives an overview of Cadence IIC Zephyr driver which is available as part of the zephyr-amd repo.

HW Features

Cadence IIC controller

Design Notes

NA

Implementation

Zephyr Cadence IIC Driver Implementation

Features Supported

Master operations
Slave operations
I2C Speeds of 100Khz and 400Khz
Repeated START
Interrupt driven
7-bit addressing (Master)
10-bit addressing (Master)
Transmit and receive FIFOs — 16 bytes (default)
APIs supported
- i2c_configure - Configure operation of a host controller
- i2c_get_config - Get configuration of a host controller
- i2c_transfer - Perform data transfer to another I2C device in controller mode
  - synchronous transfer
- i2c_target_register - Registers the provided config as Target device of a controller
- i2c_target_unregister - Unregisters the provided config as Target device

Missing Features

Does not support I2C speeds greater than 1 Mhz.
APIs not supported
- i2c_transfer_cb - Perform data transfer to another I2C device in controller mode
  - asynchronously with a callback completion
- i2c_iodev_submit - Submit requests to an I2C device with RTIO
- i2c_recover_bus - Recover the I2C bus

Known Issues

N/A

Limitations

N/A

Kernel Configuration

CONFIG_I2C=y
CONFIG_I2C_CADENCE=y

CONFIG_I2C_CADENCE is enabled by device tree status.

Device Tree

Iicps Node

ps_i2c1: i2c@ff030000 {
    compatible = "cdns,i2c-r1p14";
    status = "okay";
    #address-cells = <1>;
    #size-cells = <0>;
    reg = <0xff030000 0x1000>;
    interrupt-parent = <&gic>;
    interrupts = <GIC_SPI 18 IRQ_TYPE_LEVEL
                  IRQ_DEFAULT_PRIORITY>;
    clocks = <&i2c_ref_clk>;
};

Lopper Support to generate IICPS node is to be added
- To be discussed

Driver Stack Size

1.9 KB (Master) - i2c_cdns.c
- 1.9 KB (Master Only)
- 2.4 KB (Master + Debug Log)
- 2.9 KB for Master + Debug + i2c common
  - i2c_common.c - 0.4 KB (only in debug else approx zero)

Test Platform

Versalnet - tenzing2 se7, se9

Test SoC Architecture

RPU
- R5 core - zcu102 - Validated
- R52 core - tenzing2 se7 - Validated

Testing Sequence

Build zephyr application for board
- west build -p -b <board> <sample application path>
Run zephyr elf on board

Example Tests

Test Name

Example Source

Description

EEPROM Sample

samples/drivers/eeprom/

zcu102 - zephyr_zcu102_iicps_samples_drivers_eeprom.c (download)

EEPROM Write and Read Sample using I2C Driver API

IICPS Master Mode Example

tenzing2 se7 - zephyr_tenzing2_se7_iicps_master.c (download)

zcu102 - zephyr_zcu102_iicps_master.c (download)

Master Mode Write, Read, Repeated Start

Requires I2C Mux connected as slave
- HW Specific MUX addr, MUX channel

Expected Output

R52: tenzing2 se7 test log:

tenzing2 se7 IICPS master log

.126]Platform Version: v2.0 PMC: v2.0, PS: v2.0
[0.171]BOOTMODE: 0x0, MULTIBOOT: 0x0
[0.203]****************************************
[0.386]Non Secure Boot
[0.415]Device key init is skipped as no valid CDI is found
[4.127]PLM Initialization Time
[4.157]***********Boot PDI Load: Started***********
[4.200]Loading PDI from SBI
[4.228]Monolithic/Master Device
[4.486]0.283 ms: PDI initialization time
[4.527]+++Loading Image#: 0x1, Name: lpd, Id: 0x04210002
[4.576]---Loading Partition#: 0x1, Id: 0xC
[12.025]LPD power up. Version 0.84
[70.994]Done LPD power up.
[73.359] 68.735 ms for Partition#: 0x1, Size: 14976 Bytes
[78.401]---Loading Partition#: 0x2, Id: 0xB
[135.512] 53.249 ms for Partition#: 0x2, Size: 83792 Bytes
[137.869]+++Loading Image#: 0x2, Name: pl_cfi, Id: 0x18700000
[143.220]---Loading Partition#: 0x3, Id: 0x3
[165.516]NPD power up.
[167.144]Efuse transfer generic...
[168.061]Done NPD power up.
[170.321]HNICX power up. Version 1.2
[174.041]Efuse transfer generic...
[177.882]Done HNICX power up.
[179.308]PLPD power up.
[187.714]Efuse transfer generic...
[188.002]Done PLPD power up.
[677.956] 530.789 ms for Partition#: 0x3, Size: 803488 Bytes
[680.444]---Loading Partition#: 0x4, Id: 0x5
[1413.570] 729.178 ms for Partition#: 0x4, Size: 607216 Bytes
[1416.160]+++Loading Image#: 0x3, Name: fpd, Id: 0x0420C003
[1421.371]---Loading Partition#: 0x5, Id: 0x8
[1435.056]FPD power up. Version 0.86
WARN XPmRail_IdentifyVendor: Unable to Identify Regulator Vendor of Rail 0x432802C.		Using default Regulator: 0x0
[1450.935]Done FPD power up.
[1450.985] 25.580 ms for Partition#: 0x5, Size: 17488 Bytes
[1455.945]***********Boot PDI Load: Done***********
[1460.463]144299.473 ms: ROM Time
[1463.451]Total PLM Boot Time
I: 100 KHz mmio f1940000
*** Booting Zephyr OS build 98620ef82c12 ***
I: IIC-PS: master mode test: Start
I: IIC-PS: master: configure-test: Start
I: PS-I2C: device READY
I: PS-I2C: master: i2c_configure: Progress
I: PS-I2C: master: i2c_configure: Success
I: PS-I2C: master: i2c_get_config: Progress
I: PS-I2C: master: i2c_get_config: Success
I: IIC-PS: master: configure-test: PASSED
I: IIC-PS: master: transfer-test: Start
I: PS-I2C: i2c_transfer: write: Progress
I: PS-I2C: master: i2c_transfer: write data: 00h
I: PS-I2C: i2c_transfer: write: PASSED
I: PS-I2C: i2c_transfer: read: PASSED
I: PS-I2C: i2c_transfer: multi-msg: Progress
I: PS-I2C: i2c_transfer: multi-msg: PASSED
I: IIC-PS: master: transfer-test: PASSED
I: IIC-PS: master: rep-start-test: Start
I: PS-I2C: master: write-read-rep-start: SLAVE:EEPROM Progress
I: PS-I2C: master: write-read-rep-start: write data: 00h
I: PS-I2C: master: write-read-rep-start: SLAVE:EEPROM success
I: PS-I2C: master: write-read-rep-start: read data: 0Ch 0Dh 0Eh
I: IIC-PS: master: rep-start-test: PASSED
I: IIC-PS: master mode test: PASSED

Download zephyr_tenzing2_se7_iicps_master.log

R5: zcu102 r5 test log:

zcu102 R5 IICPS master log

I: 400 KHz mmio ff020000
I: 100 KHz mmio ff030000
*** Booting Zephyr OS build 98620ef82c12 ***
I: IIC-PS: master mode test: Start
I: IIC-PS: master: configure-test: Start
I: PS-I2C: device READY
I: PS-I2C: master: i2c_configure: Progress
I: PS-I2C: master: i2c_configure: Success
I: PS-I2C: master: i2c_get_config: Progress
I: PS-I2C: master: i2c_get_config: Success
I: IIC-PS: master: configure-test: PASSED
I: IIC-PS: master: transfer-test: Start
I: PS-I2C: i2c_transfer: write: Progress
I: PS-I2C: i2c_transfer: write: PASSED
I: PS-I2C: i2c_transfer: read: PASSED
I: PS-I2C: i2c_transfer: multi-msg: Progress
I: PS-I2C: i2c_transfer: multi-msg: PASSED
I: IIC-PS: master: transfer-test: PASSED
I: IIC-PS: master: rep-start-test: Start
I: PS-I2C: master: write-read-rep-start: SLAVE:IIC-MUX Progress
I: PS-I2C: master: write-read-rep-start: write data: 01h
I: PS-I2C: master: write-read-rep-start: SLAVE:IIC-MUX success
I: PS-I2C: master: write-read-rep-start: read data: 01h
I: IIC-PS: master: rep-start-test: PASSED
I: IIC-PS: master mode test: PASSED

Download zephyr_zcu102_r5_iicps_master.log

Code Coverage

With example Test, Code Coverage was 72.8% (Master Mode)
- Master mode coverage report (download)
- Observed 76.8 % (Master + Slave Mode) - Master + Slave coverage report (download)

Performance Metric

TBA

Mainline Status

Master Mode - Merged - https://github.com/zephyrproject-rtos/zephyr/pull/86400
Slave Mode - Under Review - https://github.com/zephyrproject-rtos/zephyr/pull/88643

Driver Source Path

drivers/i2c/i2c_cdns.c

Misra C Report

Per coding guidelines of zephyr (subset of Misra-C)
- Ref: https://docs.zephyrproject.org/latest/contribute/coding_guidelines/index.html#coding-guidelines

File	Required	Advisory
i2c_cdns.c	7	26

Detailed breakup

misra-c rule (zephyr guideline)	Severity	Kernel Utility Violations
Dir 4.8	Advisory	7
Dir 4.9	Advisory	3
Rule 1.2	Advisory	16
Rule 10.4	Required	1
Rule 21.2	Required	6
Total violations		33