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[0/2] Compute HS HCNT and LCNT based on HW parameters

Message ID 20240925080432.186408-1-michael.wu@kneron.us
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Series Compute HS HCNT and LCNT based on HW parameters | expand

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Michael Wu Sept. 25, 2024, 8:04 a.m. UTC 
In commit 35eba185fd1a ("i2c: designware: Calculate SCL timing
parameters for High Speed Mode") hs_hcnt and hs_lcnt are computed based
on fixed tHIGH = 160 and tLOW = 320. However, this fixed values only
applies to the combination of hardware parameters "IC_CAP_LOADING = 400pF"
and "IC_FREQ_OPTIMIZATION = 1". Outside of this combination, SCL frequency
may not reach 3.4 MHz if hs_hcnt and hs_lcnt are both computed using these
two fixed values.

Since there are no any registers controlling these two hardware
parameters, their values ​​can only be noted through the device tree.

Michael Wu (2):
  i2c: designware: determine HS tHIGH and tLOW based on HW paramters
  dt-bindings: i2c: snps,designware-i2c: add bus-loading and
    clk-freq-optimized

 .../bindings/i2c/snps,designware-i2c.yaml     | 19 +++++++++++++++
 drivers/i2c/busses/i2c-designware-common.c    | 16 +++++++++++++
 drivers/i2c/busses/i2c-designware-core.h      |  8 +++++++
 drivers/i2c/busses/i2c-designware-master.c    | 24 +++++++++++++++++--
 drivers/i2c/busses/i2c-designware-platdrv.c   |  2 ++
 5 files changed, 67 insertions(+), 2 deletions(-)