[v4,0/2] Introduce MediaTek CCI devfreq driver

Message

Johnson Wang May 12, 2022, 1:07 p.m. UTC

The Cache Coherent Interconnect (CCI) is the management of cache
coherency by hardware. CCI DEVFREQ is DVFS driver for power saving by
scaling clock frequency and supply voltage of CCI. CCI uses the same
input clock source and power rail as LITTLE CPUs on Mediatek SoCs.

This series depends on:
Chanwoo's repo: kernel/git/chanwoo/linux.git
branch: devfreq-testing
[1]: PM / devfreq: Export devfreq_get_freq_range symbol within devfreq
[2]: PM / devfreq: Add cpu based scaling support to passive governor
[3]: PM / devfreq: passive: Reduce duplicate code when passive_devfreq case
[4]: PM / devfreq: passive: Update frequency when start governor

Changes in v4:
- Add a maintainer in the binding document.
- Modify clock description.
- Add binding document into MAINTAINERS.
- Replace format specifier %d with %ld.

Changes in v3:
- Move binding document to 'interconnect' and rename it.
- Add COMPILE_TEST dependence symbol.
- Remove need_voltage_tracking variable.
- Move mtk_ccifreq_voltage_tracking() code into mtk_ccifreq_set_voltage().
- Add an interation limit in the while() loop.
- Replace 'cci_dev' with 'dev'
- Replace old_* with pre_*
- Remove of_match_ptr()
- Use module_platform_driver()

Changes in v2:
- Take MT8183 as example in binding document.
- Use dev_err() instead of pr_err().
- Use 'goto' statement to handle error case.
- Clean up driver code.

Johnson Wang (2):
  dt-bindings: interconnect: Add MediaTek CCI dt-bindings
  PM / devfreq: mediatek: Introduce MediaTek CCI devfreq driver

 .../bindings/interconnect/mediatek,cci.yaml   | 140 ++++++
 MAINTAINERS                                   |   1 +
 drivers/devfreq/Kconfig                       |  10 +
 drivers/devfreq/Makefile                      |   1 +
 drivers/devfreq/mtk-cci-devfreq.c             | 474 ++++++++++++++++++
 5 files changed, 626 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/interconnect/mediatek,cci.yaml
 create mode 100644 drivers/devfreq/mtk-cci-devfreq.c