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

[Violeta Menendez Gonzalez <violeta.menendez@codethink.co.uk>]

On 06/05/14 10:52, Ben Dooks wrote:
> 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.

Indeed. Adding it fixed our issue.

Thanks all.

>
>>                  <&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";
>>         ...
>>
>
>

-- 
Violeta Menéndez González	http://www.codethink.co.uk/
Software Engineer		Codethink - Providing Genius