Thread (7 messages) 7 messages, 3 authors, 2017-02-13
STALE3392d

[PATCH] Set sda-hold-time based on ACPI *CNT value

From: <hidden>
Date: 2017-02-10 11:28:46

From: Tan Chin Yew <redacted>

For I2c to operate correctly under all speed mode, sda-hold-time need to
be perfectly tuned. However, sda-hold-time is precalculated according to
circuit parameter which make it platform-specific.

In order to get accurate sda-hold-time for all platforms, pretuned
sda-hold-time for particular platform is stored in ACPI table and driver
to load the sda holding time from ACPI table.

This patch read the I2c sda-hold-time from ACPI table and assigned the
suitable hold time based on the i2c clock frequency.

Tested on Intel Apollo Lake.

Tan Chin Yew (1):
  i2c: designware: Get selected speed mode sda-hold-time via ACPI

 drivers/i2c/busses/i2c-designware-platdrv.c | 27 ++++++++++++++++++++-------
 1 file changed, 20 insertions(+), 7 deletions(-)

-- 
1.9.1
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