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[0/2] ic2: mux: pca9541: add delayed-release support

Message ID 20220124213850.3766-1-zev@bewilderbeest.net
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Series ic2: mux: pca9541: add delayed-release support | expand

Message

Zev Weiss Jan. 24, 2022, 9:38 p.m. UTC
Hello,

This series adds support for a new pca9541 device-tree property
("release-delay-us"), which delays releasing ownership of the bus
after a transaction for a configurable duration, anticipating that
another transaction may follow shortly.  By avoiding a
release/reacquisition between transactions, this can provide a
substantial performance improvement for back-to-back operations -- on
a Delta AHE-50DC (ASPEED AST1250) system running OpenBMC with LM25066
PMICs behind PCA9541-arbitrated busses, a setting of 10000 (10 ms)
reduces the median latency of reading hwmon sysfs files from 2.28 ms
to 0.99 ms (a 57% improvement).


Thanks,
Zev

Zev Weiss (2):
  i2c: mux: pca9541: add delayed-release support
  dt-bindings: i2c: add nxp,pca9541 release-delay-us property

 .../devicetree/bindings/i2c/nxp,pca9541.txt   | 10 ++++
 drivers/i2c/muxes/i2c-mux-pca9541.c           | 56 ++++++++++++++++---
 2 files changed, 57 insertions(+), 9 deletions(-)