mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-05-09 11:23:09 -04:00
7f218065c1
Allowing the lcdif_pre_sel to propagate rate changes to its parent PLL
allows more fine grained control over the LCDIF pixel clock rate.
For example, the Innovision AT043TN24 LCD panel described in the
imx6ul-14x14-evk device tree requires a 9 MHz pixel clock.
Before this patch, the lcdif_pre_sel clock rate is fixed, and just
setting the lcdif_pred and lcdif_podf dividers only allows to get as
close as about 8.44 MHz:
pll3 1 1 480000000 0 0
pll3_bypass 1 1 480000000 0 0
pll3_usb_otg 1 1 480000000 0 0
pll3_pfd1_540m 1 1 540000000 0 0
lcdif_pre_sel 1 1 540000000 0 0
lcdif_pred 1 1 67500000 0 0
lcdif_podf 1 1 8437500 0 0
lcdif_pix 1 1 8437500 0 0
Once lcdif_pre_sel is allowed to propagate rate requests to its parent,
the actual pixel clock matches the requested value:
pll3 1 1 480000000 0 0
pll3_bypass 1 1 480000000 0 0
pll3_usb_otg 1 1 480000000 0 0
pll3_pfd1_540m 1 1 288000000 0 0
lcdif_pre_sel 1 1 288000000 0 0
lcdif_pred 1 1 36000000 0 0
lcdif_podf 1 1 9000000 0 0
lcdif_pix 1 1 9000000 0 0
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.