* [PATCH] Set sda-hold-time based on ACPI *CNT value
@ 2017-02-10 11:15 chin.yew.tan
0 siblings, 0 replies; 2+ messages in thread
From: chin.yew.tan @ 2017-02-10 11:15 UTC (permalink / raw)
To: jarkko.nikula, andriy.shevchenko, mika.westerberg; +Cc: linux-i2c
From: Tan Chin Yew <chin.yew.tan@intel.com>
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
^ permalink raw reply [flat|nested] 2+ messages in thread
* [PATCH] Set sda-hold-time based on ACPI *CNT value
@ 2017-02-10 11:28 chin.yew.tan
0 siblings, 0 replies; 2+ messages in thread
From: chin.yew.tan @ 2017-02-10 11:28 UTC (permalink / raw)
To: jarkko.nikula, andriy.shevchenko, mika.westerberg; +Cc: linux-i2c
From: Tan Chin Yew <chin.yew.tan@intel.com>
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
^ permalink raw reply [flat|nested] 2+ messages in thread
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