exynos5420: re-factor clock_get_periph_rate()

This re-factors clock_get_periph_rate() to be a simpler and also
make a few corrections along the way. To summarize:

- clk_bit_info is no longer used. It had numerous errors and was
  really painful anyway since it was just a bunch of opaque magic
  numbers that made bugs non-obvious.

- Clock source bitfields for peripherals handled in the switch
  statement are 3 bits, not 4. Some divider values are 3 bits,
  some are 4. The earlier code always assumed 4 bits for both
  which included reserved bits in many cases.

- UART source clock and divider shift values were wrong.

- PWM clock divider was being read from the wrong register.

- SPI3 divider value was being read from the wrong register.

- There was a really confusing calculation for SDMMC0 and SDMMC2
  clock rates, but it was never actually used since the switch
  statement never handled PERIPH_ID_SDMMC{0,2} and would thus
  return if they were ever passed into this function.

Signed-off-by: David Hendricks <dhendrix@chromium.org>

Change-Id: I0a03a64d8b42fbe83dbf377292597ce681b22f4b
Reviewed-on: https://gerrit.chromium.org/gerrit/65284
Commit-Queue: David Hendricks <dhendrix@chromium.org>
Tested-by: David Hendricks <dhendrix@chromium.org>
Reviewed-by: Gabe Black <gabeblack@chromium.org>
Reviewed-on: http://review.coreboot.org/4463
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>

0 files changed, 0 insertions, 0 deletions