LMK05028: LMK05028 I2C driver guidance

RanjithKumar T R

Part Number: LMK05028

Hi team,

We are trying to implement a Linux kernel driver for the LMK05028 clock cleaner as per the 9.5.2 section of the SNAS724A document. (LMK05028 datasheet)

https://www.ti.com/lit/ds/snas724a/snas724a.pdf?ts=1619781515764&ref_url=https%253A%252F%252Fwww.ti.com%252Ftool%252FLMK05028EVM

It would be helpful for us if you have any sample kernel I2C read-write routines implemented in 10bit data addressing (Register Low/High).

Kindly share the appropriate development projects or documents,

over 2 years ago

0 Kia Rahbar over 2 years ago

TI__Expert 8585 points

Hello,

The LMK05028 Programming Guide (SNAU233) can be used as a reference for registers that are valid to program.

The most straightforward way to generate a configuration is to first develop the configuration using TICS Pro software. Then, after the configuration has been constructed, export the register map as a hex dump (as shown below). This is further explained in the LMK05028 programming guide.

Regards,

Kia Rahbar

0 RanjithKumar T R over 2 years ago in reply to Kia Rahbar

Prodigy 60 points

Hi Kia,

Our requirement is to dynamically write incremental/decremental step values of clock frequency adjustment obtained from the PTP stack.

That's why we are writing an i2c driver which will be invoked to write every frequency adjustment cycle.

Thanks,

0 Kia Rahbar over 2 years ago in reply to RanjithKumar T R

TI__Expert 8585 points

Hello,

Incremental/decremental step values of clock frequency can be accomplished using the LMK05028 profile on TICS Pro, specifically using the DCO Mode section (shown below).

Please perform all the necessary programming through TICS Pro, and then preform a register dump as described in my previous post to have all the required register writes you need to perform.

Regards,

Kia Rahbar

0 RanjithKumar T R over 2 years ago in reply to Kia Rahbar

Prodigy 60 points

Hello,

We cannot use TicsPro software for this requirement. Because our frequency adjustment cycle should happen almost every 100ms. That is why we are forced to write a kernel driver for this, to take care of these step_val adjustments in i2c registers

Is there - to your knowledge - any available Linux I2C library/API/driver that would create & issue the cascaded I2C transactions (without the STOP condition) required to program the LMK05028 registers, as per 9.5.2 of

https://www.ti.com/lit/ds/symlink/lmk05028.pdf?ts=1608278564277&ref_url=https%253A%252F%252Fwww.ti.com%252Fclocks-timing%252Fjitter-cleaners-synchronizers%252Foverview.html?

0 Kia Rahbar over 2 years ago in reply to RanjithKumar T R

TI__Expert 8585 points

Hello,

Unfortunately, we do not have any libraries/APIs. If TICS Pro cannot be used, the best I can provide you is the LMK05028 Programming Guide (SNAU233) which can be used to determine the valid register writes.

Regards,

Kia Rahbar

Clock & timing

Clock & timing forum

LMK05028: LMK05028 I2C driver guidance