Re: [PATCH 5/5 v3] clk: ux500: Implement the missing CLKOUT clocks

[Stephen Boyd <sboyd@kernel.org>]

Quoting Linus Walleij (2022-04-14 15:17:51)
> This implements the two missing CLKOUT clocks for the ux500
> (well really U8500/DB8500) SoC.
> 
> The clocks are initialized using a specific parent and
> divider and these are specified in the device tree, see
> the separate binding patch.
> 
> The implementation is a bit different in that it will only
> create the clock in the clock framework if a user appears
> in the device tree, rather than it being registered upfront
> like most of the other clocks. This is because the clock
> needs parameters for source and divider from the consumer
> phandle for the clock to be set up properly when the clock
> is registered.
> 
> There could be more than one user of a CLKOUT clock, but
> we have not seen this in practice. If this happens the
> framework prints and info and returns the previously
> registered clock.
> 
> Using the clocks requires also muxing the CLKOUT1 or
> CLKOUT2 to the appropriate pad. In practice this is
> achived in a pinctrl handle in the DTS node for the device
> using the CLKOUT clock, so this muxing is done separately
> from the clock itself. Example:
> 
>   haptic@49 {
>     compatible = "immersion,isa1200";
>     reg = <0x49>;
>     (...)
>     /* clkout1 from ACLK divided by 8 */
>     clocks = <&clkout_clk DB8500_CLKOUT_1 DB8500_CLKOUT_SRC_ACLK 8>;
>     pinctrl-names = "default";
>     pinctrl-0 = <&isa1200_janice_default>;
>   };
> 
>   isa1200_janice_default: isa1200_janice {
>     /* Bring out clkout1 on pin GPIO227 pin AH7 */
>     janice_mux {
>       function = "clkout";
>       groups = "clkout1_a_1";
>     };
>     janice_cfg1 {
>       pins = "GPIO227_AH7";
>       ste,config = <&out_lo>;
>     };
>   (...)
> 
> This was tested successfully with the Immersion ISA1200
> haptic feedback unit on the Samsung Galaxy S Advance GT-I9070
> (Janice) mobile phone.
> 
> As the CLKOUT clocks need some undefined fixed rate parent
> clocks that are currently missing from the PRCMU clock
> implementation, the three simplest are added in this patch:
> clk38m_to_clkgen, aclk and sysclk. The only parent not yet
> available in the implementation is clk009, which is a kind
> of special muxed and divided clock which isn't even
> implemented in the vendor clock driver.
> 
> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> ---

Applied to clk-next