HW IP Features
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Introduction
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| Table of Contents |
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Introduction
This page provides information about the Cadence I2C driver which can be found on Xilinx Git and mainline as i2c-cadence.c
Zynq has two I2C hard IP. I2C can be used as a master with this linux driver.
There is support for repeated start with some limitations.
HW IP Features
- Master mode
- Support 16 bytes FIFO
- Programmable normal and fast bus data rates
- Interrupt support
- Repeated start support using HOLD bit
- FIFO control using HOLD bit
- Slave monitoring support in Master mode.
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- Repeated start after a read transfer is not supported by this controller. A warning is given when this condition is detected by the driver.
- The following are the controller errata:
- Missing glitch filter.
- I2C Master Generates Invalid Read Transactions
- Missing I2C Master Completion Interrupt.
- Timing requirement violations
- I2C - Standard Mode running faster than 90 kHz violates tHD; STA timing requirement.
- I2C - Fast Mode running faster than 384kHz violates tLOW; STA timing requirement.
- I2C - Fast Mode running faster than 384 kHz violates tBUF; STA timing requirement.
- I2C Missing Arbitration On Repeated Start.
Multi-master configuration works only if all the participating masters are operating at the same frequency.
Important AR links
- Zynq-7000 AP SoC, I2C - Missing Glitch Filter Implementation in Zynq PS I2C Controller AR# 61861
- Zynq-7000 AP SoC, I2C - I2C Master Generates Invalid Read Transactions AR# 61664
- Zynq-7000 AP SoC, I2C - Missing I2C Master Completion Interrupt AR# 61665
- Zynq-7000 AP SoC, I2C - I2C Missing Arbitration on Repeated Start AR# 60695
- Zynq-7000 AP SoC, I2C - Standard Mode running faster than 90 kHz violates tHD; STA timing requirement AR# 59366
- Zynq-7000 AP SoC, I2C - Fast Mode running faster than 384kHz violates tLOW; STA timing requirement AR# 60693
- Zynq-7000 AP SoC, I2C - Fast Mode running faster than 384 kHz violates tBUF; STA timing requirement AR# 60694
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| Code Block | ||
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- dd if=/dev/urandom of/urandom of=eeprom_in.bin bs=1 count=128 skip=0 128+0 records in 128+0 records out 128 bytes (128B) copied, 0.001327 seconds, 94.2KB/s |
2. Write BIN file to EEPROM
| Code Block | ||
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- dd if=eeprom_in.bin of=/sys/bus/i2c/devices/0-0054/eeprom bs=1 count=128 skip=0 128+0 records in 128+0 records out 128 bytes (128B) copied, 02.001327539178 seconds, 94.2KB50B/s |
2. Write BIN file to 3. Read Data From EEPROM
| Code Block | ||
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- dd if=eeprom_in.bin of=/sys/bus/i2c/devices/0-0054/eeprom of=eeprom_out.bin bs=1 count=128 skip=0 128+0 records in 128+0 records out 128 bytes (128B) copied, 2.539178 seconds, 50B/s |
3. Read Data From EEPROM
| Code Block | ||
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- dd if=/sys/bus/i2c/devices/0-0054/eeprom of=eeprom_out.bin bs=1 count=128 skip=0
128+0 records in
128+0 records out
128 bytes (128B) copied, 0.065103 seconds, 1.9KB/s |
Expected Output
Verify data using md5sum tools
| Code Block | ||
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- md5sum eeprom_in.bin eeprom_out.bin
e83e141e1d9f71b3f820652f502239d2 eeprom_in.bin
e83e141e1d9f71b3f820652f502239d2 eeprom_out.bin |
Mainline Status
This driver is currently in sync with mainline kernel driver.
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128+0 records in
128+0 records out
128 bytes (128B) copied, 0.065103 seconds, 1.9KB/s |
Expected Output
Verify data using md5sum tools
| Code Block | ||
|---|---|---|
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- md5sum eeprom_in.bin eeprom_out.bin
e83e141e1d9f71b3f820652f502239d2 eeprom_in.bin
e83e141e1d9f71b3f820652f502239d2 eeprom_out.bin |
Mainline Status
This driver is currently in sync with mainline kernel driver.
ChangeLog
2024.1
Summary
- Remove unused CDNS_I2C_DATA_INTR_DEPTH define
- Remove
irqfield from driver state struct - Remove redundant expression in if clause
- Remove always false ternary operator
- Remove unnecessary register reads
- Allow to specify the FIFO depth
- Detect maximum transfer size
- Add reset controller support
- Fix runtime PM leak on error path
- Convert to platform remove callback returning void
- Fix the kernel-doc warnings
Commits
72f94ff - i2c: cadence: Remove unused CDNS_I2C_DATA_INTR_DEPTH define
2264997 - i2c: cadence: Remove irq field from driver state struct
a4a1a78 - i2c: cadence: Remove redundant expression in if clause
e9d373c - i2c: cadence: Remove always false ternary operator
ff0cf7b - i2c: cadence: Remove unnecessary register reads
a069fcd - i2c: cadence: Allow to specify the FIFO depth
ba06487 - i2c: cadence: Detect maximum transfer size
0cbc9a2 - i2c: cadence: Add reset controller support
ae1664f - i2c: cadence: cdns_i2c_master_xfer(): Fix runtime PM leak on error path
e190a0c - i2c: Convert to platform remove callback returning void