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The DSP DPLL is a new DPLL compared to previous OMAP generations and supplies the root clocks for the DSP processors, as well as a mux input source for EVE sub-system (on applicable SoCs). This DPLL is currently not configured by older bootloaders. Use the DT standard properties "assigned-clocks" and "assigned-clock-rates" to set the DSP 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 DSP DPLL provides two output clocks, DSP_GFCLK and EVE_GCLK. The desired rate for DSP_GFCLK is 600 MHz (same as DSP DPLL CLKOUT frequency), and is currently auto set due to the desired M2 divider value being the same as reset value for the locked frequency of 600 MHz. The EVE_GCLK however is required to be 400 MHz, so set the dpll_dsp_m3x2_ck's rate explicitly so that the divider is set properly. The dpll_dsp_m2_ck rate is also set explicitly to not rely on any implicit matching divider reset values to the locked DPLL frequency. 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 1200 MHz, so the dpll_dsp_ck clock rate used is half of this value. 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.