[lkml]   [2020]   [May]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH v3 3/4] clk: Add Baikal-T1 CCU PLLs driver
Quoting Serge Semin (2020-05-26 15:20:55)
> Baikal-T1 is supposed to be supplied with a high-frequency external
> oscillator. But in order to create signals suitable for each IP-block
> embedded into the SoC the oscillator output is primarily connected to
> a set of CCU PLLs. There are five of them to create clocks for the MIPS
> P5600 cores, an embedded DDR controller, SATA, Ethernet and PCIe domains.
> The last three domains though named by the biggest system interfaces in
> fact include nearly all of the rest SoC peripherals. Each of the PLLs is
> based on True Circuits TSMC CLN28HPM IP-core with an interface wrapper
> (so called safe PLL' clocks switcher) to simplify the PLL configuration
> procedure.
> This driver creates the of-based hardware clocks to use them then in
> the corresponding subsystems. In order to simplify the driver code we
> split the functionality up into the PLLs clocks operations and hardware
> clocks declaration/registration procedures.
> Even though the PLLs are based on the same IP-core, they may have some
> differences. In particular, some CCU PLLs support the output clock change
> without gating them (like CPU or PCIe PLLs), while the others don't, some
> CCU PLLs are critical and aren't supposed to be gated. In order to cover
> all of these cases the hardware clocks driver is designed with an
> info-descriptor pattern. So there are special static descriptors declared
> for each PLL, which is then used to create a hardware clock with proper
> operations. Additionally debugfs-files are provided for each PLL' field
> to make sure the implemented rate-PLLs-dividers calculation algorithm is
> correct.
> Signed-off-by: Serge Semin <>
> Cc: Alexey Malahov <>
> Cc: Arnd Bergmann <>
> Cc: Rob Herring <>
> Cc:
> Cc:
> ---

Applied to clk-next

 \ /
  Last update: 2020-05-30 20:15    [W:0.087 / U:0.256 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site