Re: [alsa-devel] r8a7790 only has audio when clock is forced on

[Ben Dooks <ben.dooks@codethink.co.uk>]

On 05/06/14 10:35, Kuninori Morimoto wrote:
> 
> Hi Violeta
> 
>>> SSI(ALL) bit mean "this bit is always required for all SSI"
>>> If you want to use SSI0, then, you need to enable "SSI(ALL) + SSI0" bit
>>>
>>
>> We have to force SSI(ALL) to stay always on on the DT with a special 
>> property, like this:
>> always-on = <0x00000020>;
>>
>> we don't need to force SSI0 on, although it is necessary for audio that 
>> this clock is on too.
>>
>> The code for mstp10 correctly enables SSI0 *and* SSI(ALL). But it only 
>> works when SSI(ALL) is forced on the DT.
> (snip)
>> Where index 5 is SSI(ALL) and index 15 is SSI0.
>> We can observe that when we force SSI(ALL) on on the DT, then 
>> clock_disable is called for SSI(ALL) before it enables again.
>> But when we don't force SSI(ALL) to be on, then it only calls 
>> clock_enable, but the register data is the same.
>>
>> This looks like the correct behaviour, but in one case we have audio, 
>> and in the other we don't.
>>
>> I hope this clarifies the problem a bit more.
> 
> I understand your point on DT with SSI(ALL).
> I didn't send R-Car sound DT support patch yet for some reasons.
> But, R-Car sound clock needs trick.
> 
>  - SSI(ALL) is called via pm_runtime_xxx() from sound driver
>  - SRC(ALL) is called as parent clock of SRCn clocks

See, this is why I /hate/ the implicit clock management. This is
another case where we're getting bitten by it.

> This is implemented on legacy clock-r8a7790.c too.
> So, I think "always-on" is not needed for sound driver.
> 
> My local DTS file is below.
> (not enough maintenance though...)
> 
> It is very nice if you can wait for my DT patches,
> since R-Car sound driver is very complex / needs some trick etc...
> 
>      mstp10_clks: mstp10_clks@e6150998 {
>                 compatible = "renesas,r8a7790-mstp-clocks", "renesas,cpg-mstp-clocks";
>                 reg = <0 0xe6150998 0 4>, <0 0xe61509a8 0 4>;
>                 clocks = <&p_clk>, /* parent of SCU */
>                         <&p_clk>,
>                         <&p_clk>, <&p_clk>, <&p_clk>, <&p_clk>, <&p_clk>,
>                         <&p_clk>, <&p_clk>, <&p_clk>, <&p_clk>, <&p_clk>,

we have these as <&mstp10_clks R8A7790_CLK_SSI>

>                         <&mstp10_clks R8A7790_CLK_SCU>, <&mstp10_clks R8A7790_CLK_SCU>,
>                         <&mstp10_clks R8A7790_CLK_SCU>, <&mstp10_clks R8A7790_CLK_SCU>,
>                         <&mstp10_clks R8A7790_CLK_SCU>, <&mstp10_clks R8A7790_CLK_SCU>,
>                         <&mstp10_clks R8A7790_CLK_SCU>, <&mstp10_clks R8A7790_CLK_SCU>,
>                         <&mstp10_clks R8A7790_CLK_SCU>, <&mstp10_clks R8A7790_CLK_SCU>,
>                         <&mstp10_clks R8A7790_CLK_SCU>, <&mstp10_clks R8A7790_CLK_SCU>;
>                   #clock-cells = <1>;
>                 clock-indices = <
>                         R8A7790_CLK_SCU
>                         R8A7790_CLK_SSI
>                         R8A7790_CLK_SSI9 R8A7790_CLK_SSI8 R8A7790_CLK_SSI7 R8A7790_CLK_SSI6 R8A7790_CLK_SSI5
>                         R8A7790_CLK_SSI4 R8A7790_CLK_SSI3 R8A7790_CLK_SSI2 R8A7790_CLK_SSI1 R8A7790_CLK_SSI0
>                         R8A7790_CLK_DVC1 R8A7790_CLK_DVC0
>                         R8A7790_CLK_SRC9 R8A7790_CLK_SRC8 R8A7790_CLK_SRC7 R8A7790_CLK_SRC6 R8A7790_CLK_SRC5
>                         R8A7790_CLK_SRC4 R8A7790_CLK_SRC3 R8A7790_CLK_SRC2 R8A7790_CLK_SRC1 R8A7790_CLK_SRC0
>                 >;
>                 clock-output-names >                         "scu", "ssi",
>                         "ssi9", "ssi8", "ssi7", "ssi6", "ssi5",
>                         "ssi4", "ssi3", "ssi2", "ssi1", "ssi0",
>                         "dvc1", "dvc0",
>                         "src9", "src8", "src7", "src6", "src5",
>                         "src4", "src3", "src2", "src1", "src0";
>         };
> 
> ...
> 
> rcar_sound: rcar_sound@0xec500000 {
>         #sound-dai-cells = <1>;
>         compatible =  "renesas,rcar_sound-r8a7790", "renesas,rcar_sound-gen2", "renesas,rcar_sound";
>         interrupt-parent = <&gic>;
>         reg =   <0 0xec500000 0 0x1000>, /* SCU */
>                 <0 0xec5a0000 0 0x100>,  /* ADG */
>                 <0 0xec540000 0 0x1000>, /* SSIU */
>                 <0 0xec541000 0 0x1280>; /* SSI */
>         clocks = <&mstp10_clks R8A7790_CLK_SSI>,

I don't think we have this one here.

>                 <&mstp10_clks R8A7790_CLK_SSI9>, <&mstp10_clks R8A7790_CLK_SSI8>,
>                 <&mstp10_clks R8A7790_CLK_SSI7>, <&mstp10_clks R8A7790_CLK_SSI6>,
>                 <&mstp10_clks R8A7790_CLK_SSI5>, <&mstp10_clks R8A7790_CLK_SSI4>,
>                 <&mstp10_clks R8A7790_CLK_SSI3>, <&mstp10_clks R8A7790_CLK_SSI2>,
>                 <&mstp10_clks R8A7790_CLK_SSI1>, <&mstp10_clks R8A7790_CLK_SSI0>,
>                 <&mstp10_clks R8A7790_CLK_SRC9>, <&mstp10_clks R8A7790_CLK_SRC8>,
>                 <&mstp10_clks R8A7790_CLK_SRC7>, <&mstp10_clks R8A7790_CLK_SRC6>,
>                 <&mstp10_clks R8A7790_CLK_SRC5>, <&mstp10_clks R8A7790_CLK_SRC4>,
>                 <&mstp10_clks R8A7790_CLK_SRC3>, <&mstp10_clks R8A7790_CLK_SRC2>,
>                 <&mstp10_clks R8A7790_CLK_SRC1>, <&mstp10_clks R8A7790_CLK_SRC0>,
>                 <&audio_clk_a>, <&audio_clk_b>, <&audio_clk_c>, <&m2_clk>;
>         clock-names = "ssi",
>                         "ssi.9", "ssi.8", "ssi.7", "ssi.6", "ssi.5",
>                         "ssi.4", "ssi.3", "ssi.2", "ssi.1", "ssi.0",
>                         "src.9", "src.8", "src.7", "src.6", "src.5",
>                         "src.4", "src.3", "src.2", "src.1", "src.0",
>                         "clk_a", "clk_b", "clk_c", "clk_i";
>        ...
> 


-- 
Ben Dooks				http://www.codethink.co.uk/
Senior Engineer				Codethink - Providing Genius