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Mika Westerberg authored
Intel Skylake the LPSS I2C pad circuit has internal delays that require programming non-zero SDA hold time for the I2C host controller. If this is not done communication to slave devices may fail with arbitration lost errors like the one seen below taken from Lenovo Yoga 900: i2c_hid i2c-SYNA2B29:00: Fetching the HID descriptor i2c_hid i2c-SYNA2B29:00: __i2c_hid_command: cmd=20 00 i2c_designware i2c_designware.1: i2c_dw_handle_tx_abort: lost arbitration To fix this we follow what the Windows driver is doing and pass the default SDA hold time of 230 ns to all Intel Skylake host controllers. This still allows the platform to override these values by passing special ACPI methods SSCN and FMCN. Reported-by: Kevin Fenzi <kevin@scrye.com> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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