[V2,0/4] clk: imx: Improve imx8mm/imx8mn LCDIF clocks

Message

Adam Ford March 23, 2023, 10:51 p.m. UTC

Both the i.MX8M Mini and Nano have a video_pll which can be used 
to source a clock which feeds the lcdif interface.  This interface
currently fixes video_pll and divides down the clock feeding LCDIF.
However, when connected to an HDMI bridge chip that supports a
variety of video resolutions and refresh rates, the only settings
that properly sync are ones that evenly divide from the video_pll_out
clock.

This series adds the ability for the clk-compolsite-8m to
request a better parent clock rate if the proper clock flag is
enable and sets that flag in the corresponding imx8mm and 
imx8mn video_pll clocks to increase the number of resolutions
and refresh rates timings that the LCDIF can produce.

This also has a side benefit of allowing the video-pll to run
at a lower clock speed which can potentially save some power
depending on the requested resolution and refresh rate.

V3:  Change the name of clk_divider_determine_rate to
      imx8m_clk_divider_determine_rate
V2:  Split off the new imx8m_clk_hw_composite_flags definition
     into its own patch and re-order to fix build error.
      
Adam Ford (3):
  clk: imx: composite-8m: Add support to determine_rate
  clk: imx8mm: Let IMX8MM_CLK_LCDIF_PIXEL set parent rate
  clk: imx: Let IMX8MN_CLK_DISP_PIXEL set parent rate

 drivers/clk/imx/clk-composite-8m.c | 7 +++++++
 drivers/clk/imx/clk-imx8mm.c       | 2 +-
 drivers/clk/imx/clk-imx8mn.c       | 2 +-
 drivers/clk/imx/clk.h              | 4 ++++
 4 files changed, 13 insertions(+), 2 deletions(-)