The patch enables spread spectrum clocking (SSC) for MPU and LCD PLLs.
As reported by the TI spruh73x/spruhl7x RM, SSC is only supported for
the DISP/LCD and MPU PLLs on am33xx/am43xx. SSC is not supported for
DDR, PER, and CORE PLLs.
Calculating the required values and setting the registers accordingly
was taken from the set_mpu_spreadspectrum routine contained in the
arch/arm/mach-omap2/am33xx/clock_am33xx.c file of the u-boot project.
In locked condition, DPLL output clock = CLKINP *[M/N]. In case of
SSC enabled, the reference manual explains that there is a restriction
of range of M values. Since the clk_ti_am3_dpll_round_rate() attempts
to select the minimum possible N, the value of M obtained is not
guaranteed to be within the range required. With the new "ti,min-div"
parameter it is possible to increase N and consequently M to satisfy the
constraint imposed by SSC.
Link: https://lore.kernel.org/r/20210606202253.31649-6-dariobin@libero.it
Signed-off-by: Dario Binacchi <dariobin@libero.it>
Using the custom TI functions required not only replacing common memory
access functions but also rewriting the routines used to set bypass and
lock states. As for readl() and writel(), they also required the address
of the register to be accessed, a parameter that is hidden by the TI clk
module.
Signed-off-by: Dario Binacchi <dariobin@libero.it>
Something was wrong in the merge process into the mainline.
Some added patches access driver structure fields and functions that
have been modified by previous patches.
The patch renames:
- dev_get_platdata to dev_get_plat
- dev_get_uclass_platdata to dev_get_uclass_plat
- ofdata_to_platdata to of_to_plat
- plat_data_alloc_size to plat_auto
- priv_auto_alloc_size to priv_auto
- video_uc_platdata to video_uc_plat
Signed-off-by: Dario Binacchi <dariobin@libero.it>
The digital phase-locked loop (DPLL) provides all interface clocks and
functional clocks to the processor of the AM33xx device. The AM33xx
device integrates five different DPLLs:
* Core DPLL
* Per DPLL
* LCD DPLL
* DDR DPLL
* MPU DPLL
The patch adds support for the compatible strings:
* "ti,am3-dpll-core-clock"
* "ti,am3-dpll-no-gate-clock"
* "ti,am3-dpll-no-gate-j-type-clock"
* "ti,am3-dpll-x2-clock"
The code is loosely based on the drivers/clk/ti/dpll.c drivers of the
Linux kernel version 5.9-rc7.
For DT binding details see:
- Documentation/devicetree/bindings/clock/ti/dpll.txt
Signed-off-by: Dario Binacchi <dariobin@libero.it>
