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. Changes in V3: - Remove null handling in function dw_i2c_acpi_params. - Add descriptions to commit message. Changes in V2: - The code is realigned according to suggestion. - "case 400000:" is added on top of "default:" for readability. Tan Chin Yew (1): i2c: designware: Get selected speed mode sda-hold-time via ACPI drivers/i2c/busses/i2c-designware-platdrv.c | 31 ++++++++++++++++++++--------- 1 file changed, 22 insertions(+), 9 deletions(-) -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
