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The IVA DPLL in DRA7xx provides the output clocks for only the IVAHD subsystem in DRA7xx as compared to previous OMAP generations when it provided the clocks for both DSP and IVAHD subsystems. This DPLL is currently not configured by older bootloaders. Use the DT standard properties "assigned-clocks" and "assigned-clock-rates" to set the IVA DPLL clock rate and the rates for its derivative clocks at boot time to properly initialize/lock this DPLL and be independent of the bootloader version. Newer u-boots (from 2017.01 onwards) reuse and can update these properties to choose an appropriate one-time fixed OPP configuration. The DPLL will automatically transition into a low-power stop mode when the associated output clocks are not utilized or gated automatically. The reset value of the divider M2 (that supplies the IVA_GFLCK, the functional clock for the IVAHD subsystem) does not match a specific OPP. So, the derived output clock from this IVA DPLL has to be initialized as well to avoid initializing these divider outputs to an incorrect frequencies. The OPP_NOM clock frequencies are defined in the AM572x SR2.0 Data Sheet vB, section 5.5.2 "Voltage And Core Clock Specifications". The clock rates are chosen based on these OPP_NOM values and defined as per a DRA7xx PLL spec document. The DPLL locked frequency is 2300 MHz, so the dpll_iva_ck clock rate used is half of this value. The value for the divider clock, dpll_iva_m2_ck, has to be set to 388.333334 MHz or more for the divider clk logic to compute the appropriate divider value for OPP_NOM. Signed-off-by: Suman Anna <s-anna@ti.com> Acked-by: Tero Kristo <t-kristo@ti.com> Signed-off-by: Tony Lindgren <tony@atomide.com>
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.