pwm: lpss: Fix base_unit calculation for PWM frequency

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The base_unit calculation applies an offset of 0x2 which adds
significant error for lower frequencies and doesn't appear to be
warranted - rounding the division result gives a correct value.

Also, the upper limit check for base_unit is off-by-one; the upper
nibble of base_unit is invalid if >=128 according to the Table 88
in the Z8000 Processor Series Datasheet Volume 1 (Rev. 2).

Verified on UP Board (Cherry Trail) and Minnowboard Max (Bay Trail).

Signed-off-by: Dan O'Donovan <dan@emutex.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

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Dan O'Donovan 2016-06-01 15:31:12 +01:00 • committed by Thierry Reding

parent cc37655e6b

commit e5ca42458b

1 changed files with 3 additions and 5 deletions

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drivers/pwm/pwm-lpss.c

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