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Date: Mon, 9 May 2016 13:18:06 +0200
From: "H. Nikolaus Schaller" <hns@...delico.com>
To: Tero Kristo <t-kristo@...com>
Cc: Peter Ujfalusi <peter.ujfalusi@...com>,
Tony Lindgren <tony@...mide.com>,
Benoît Cousson <bcousson@...libre.com>,
Rob Herring <robh+dt@...nel.org>,
Pawel Moll <pawel.moll@....com>,
Mark Rutland <mark.rutland@....com>,
Ian Campbell <ijc+devicetree@...lion.org.uk>,
Kumar Gala <galak@...eaurora.org>,
Russell King <linux@....linux.org.uk>,
Laxman Dewangan <ldewangan@...dia.com>,
linux-omap <linux-omap@...r.kernel.org>,
devicetree@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>,
Marek Belisko <marek@...delico.com>, kernel@...a-handheld.com,
Discussions about the Letux Kernel
<letux-kernel@...nphoenux.org>
Subject: Re: [PATCH v2 4/5] ARM: dts: omap5: describe control for ckobuffer
Hi,
> Am 28.04.2016 um 15:23 schrieb Tero Kristo <t-kristo@...com>:
>
> On 28/04/16 12:12, H. Nikolaus Schaller wrote:
>> Hi Tero,
>>
>>> Am 28.04.2016 um 10:03 schrieb Tero Kristo <t-kristo@...com>:
>>>
>>> On 27/04/16 17:35, H. Nikolaus Schaller wrote:
>>>> HI,
>>>>
>>>>> Am 27.04.2016 um 16:23 schrieb Peter Ujfalusi <peter.ujfalusi@...com>:
>>>>>
>>>>> On 04/27/2016 05:10 PM, Tero Kristo wrote:
>>>>>> On 27/04/16 16:10, H. Nikolaus Schaller wrote:
>>>>>>>
>>>>>>>> Am 27.04.2016 um 14:31 schrieb Tero Kristo <t-kristo@...com>:
>>>>>>>>
>>>>>>>> On 27/04/16 09:04, H. Nikolaus Schaller wrote:
>>>>>>>>>
>>>>>>>>>> Am 26.04.2016 um 19:27 schrieb Tony Lindgren <tony@...mide.com>:
>>>>>>>>>>
>>>>>>>>>> Tero,
>>>>>>>>>>
>>>>>>>>>> * H. Nikolaus Schaller <hns@...delico.com> [160418 11:23]:
>>>>>>>>>>> OMAP5 has a register to control if the ckobuffer is enabled
>>>>>>>>>>> and defines the polarity. ckobuffer is required to drive a twl6040
>>>>>>>>>>> with the system clock. Hence, add the pinctrl,single to the
>>>>>>>>>>> OMAP5 SoC description so that omap5-board-common can
>>>>>>>>>>> set up the ckobuffer as required.
>>>>>>>>>>
>>>>>>>>>> Is this really a mux or should it be a mux clock?
>>>>>>>>>
>>>>>>>>> It is a pinmux setting for the clock out buffer to choose what signal
>>>>>>>>> (and polarity) is presented on the fref_xtal_clk pad.
>>>>>>>>>
>>>>>>>>> The register is part of the CTRL_MODULE_WKUP.
>>>>>>>>> The clock signal is the xtal master clock of the whole SoC.
>>>>>>>>>
>>>>>>>>> Although there is a bit to choose an alternate clock, there is no
>>>>>>>>> alternate in the OMAP5 silicon.
>>>>>>>>>
>>>>>>>>> Therefore I would say it is about padconf and not clock or clock mux
>>>>>>>>> related.
>>>>>>>>>
>>>>>>>>> It just happens to be a clock signal which can be routed to this
>>>>>>>>> pad.
>>>>>>>>
>>>>>>>> The two could very well be implemented as clock nodes, a mux and a gate.
>>>>>>>> This would describe the hardware functionality better imo, if the
>>>>>>>> assumptions made here are correct. Implementing the control as pinctrl
>>>>>>>> hacks looks rather weird to me.
>>>>>>>
>>>>>>> Why do you consider it a "pinctrl hack"? IMHO it is not a hack, but 100%
>>>>>>> proper use of pinctrl.
>>>>>>
>>>>>> It is just the level of abstraction we are talking about here. If it is a
>>>>>> clock we are controlling, we should rather control it as a clock (higher level
>>>>>> abstraction), not a pin.
>>>>>
>>>>> I second this. I think it is better to have a simple gate clock and handle
>>>>> only CONTROL_CKOBUFFER:CKOBUFFER_CLK_EN (bit 28) only as the other bits does
>>>>> not have real use.
>>>>>
>>>>> Then we can add clk API support for this. On most OMAP4 devices the clock is
>>>>> always on,
>>>>
>>>> this is why I am raising the question if we really want to control it on the omap5 or just
>>>> turn it on for all omap5 boards like the omap4 appears to do... I.e. if turning the pin on
>>>> as a pinctrl is IMHO sufficient for all practical purposes.
>>>>
>>>>> so the board DTS file need to provide a dummy clock, or we can make
>>>>> the high precision clock also as optional (on panda both OMAP4 and twl6040
>>>>> uses the same reference clock).
>>>>
>>>> Hm. It looks as if implementing this (and clock gating) is beyond my experiences.
>>>> But I am happy to test a proposal on our omap5 board.
>>>>
>>>> BR and thanks,
>>>> Nikolaus
>>>
>>> See the inline patch, this implements the fref_xtal_ck. I had to add some kernel code also to cope with the new SCM area, but the same area can now be accessed via syscon also if needed.
>>
>> Looks interesting, although quite complex to enable a single SoC pad at boot time...
>
> Yea it gives plenty of other things for you also. syscon, integration with clock framework, etc.
>
>>
>> Will asap study how it works and test. And of course report results.
>
> Thanks, Tero.
>
>>
>> Thanks and BR,
>> Nikolaus
>>
>>>
>>> From: Tero Kristo <t-kristo@...com>
>>> Date: Thu, 28 Apr 2016 11:00:57 +0300
>>> Subject: [PATCH] ARM: omap5: add support for fref_xtal_ck
>>>
>>> Signed-off-by: Tero Kristo <t-kristo@...com>
>>> ---
>>> arch/arm/boot/dts/omap5.dtsi | 22 ++++++++++++++++++++++
>>> arch/arm/boot/dts/omap54xx-clocks.dtsi | 10 ++++++++++
>>> arch/arm/mach-omap2/control.c | 20 ++++++++++++++++----
>>> include/linux/clk/ti.h | 1 +
>>> 4 files changed, 49 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/arch/arm/boot/dts/omap5.dtsi b/arch/arm/boot/dts/omap5.dtsi
>>> index 38805eb..bdc6528 100644
>>> --- a/arch/arm/boot/dts/omap5.dtsi
>>> +++ b/arch/arm/boot/dts/omap5.dtsi
>>> @@ -277,6 +277,28 @@
>>> pinctrl-single,register-width = <16>;
>>> pinctrl-single,function-mask = <0x7fff>;
>>> };
>>> +
>>> + omap5_scm_wkup_pad_conf: omap5_scm_wkup_pad_conf@...0 {
>>> + compatible = "ti,omap5-scm-wkup-pad-conf",
>>> + "simple-bus";
>>> + reg = <0xcda0 0x60>;
>>> + #address-cells = <1>;
>>> + #size-cells = <1>;
>>> + ranges = <0 0xcda0 0x60>;
>>> +
>>> + scm_wkup_pad_conf: scm_conf@0 {
>>> + compatible = "syscon", "simple-bus";
>>> + reg = <0x0 0x60>;
>>> + #address-cells = <1>;
>>> + #size-cells = <1>;
>>> + ranges = <0 0x0 0x60>;
>>> +
>>> + scm_wkup_pad_conf_clocks: clocks@0 {
>>> + #address-cells = <1>;
>>> + #size-cells = <0>;
>>> + };
>>> + };
>>> + };
>>> };
>>>
>>> ocmcram: ocmcram@...00000 {
>>> diff --git a/arch/arm/boot/dts/omap54xx-clocks.dtsi b/arch/arm/boot/dts/omap54xx-clocks.dtsi
>>> index 83b425f..f970dac 100644
>>> --- a/arch/arm/boot/dts/omap54xx-clocks.dtsi
>>> +++ b/arch/arm/boot/dts/omap54xx-clocks.dtsi
>>> @@ -1388,3 +1388,13 @@
>>> reg = <0x021c>;
>>> };
>>> };
>>> +
>>> +&scm_wkup_pad_conf_clocks {
>>> + fref_xtal_ck: fref_xtal_ck {
>>> + #clocks-cells = <0>;
>>> + compatible = "ti,gate-clock";
>>> + clocks = <&sys_clkin>;
>>> + ti,bit-shift = <28>;
>>> + reg = <0x14>;
>>> + };
>>> +};
>>> diff --git a/arch/arm/mach-omap2/control.c b/arch/arm/mach-omap2/control.c
>>> index 1662071..5956641 100644
>>> --- a/arch/arm/mach-omap2/control.c
>>> +++ b/arch/arm/mach-omap2/control.c
>>> @@ -623,6 +623,7 @@ void __init omap3_ctrl_init(void)
>>>
>>> struct control_init_data {
>>> int index;
>>> + void __iomem *mem;
>>> s16 offset;
>>> };
>>>
>>> @@ -635,6 +636,10 @@ static const struct control_init_data omap2_ctrl_data = {
>>> .offset = -OMAP2_CONTROL_GENERAL,
>>> };
>>>
>>> +static const struct control_init_data ctrl_aux_data = {
>>> + .index = TI_CLKM_CTRL_AUX,
>>> +};
>>> +
>>> static const struct of_device_id omap_scrm_dt_match_table[] = {
>>> { .compatible = "ti,am3-scm", .data = &ctrl_data },
>>> { .compatible = "ti,am4-scm", .data = &ctrl_data },
>>> @@ -644,6 +649,7 @@ static const struct of_device_id omap_scrm_dt_match_table[] = {
>>> { .compatible = "ti,dm816-scrm", .data = &ctrl_data },
>>> { .compatible = "ti,omap4-scm-core", .data = &ctrl_data },
>>> { .compatible = "ti,omap5-scm-core", .data = &ctrl_data },
>>> + { .compatible = "ti,omap5-scm-wkup-pad-conf", .data = &ctrl_aux_data },
>>> { .compatible = "ti,dra7-scm-core", .data = &ctrl_data },
>>> { }
>>> };
>>> @@ -660,15 +666,21 @@ int __init omap2_control_base_init(void)
>>> struct device_node *np;
>>> const struct of_device_id *match;
>>> struct control_init_data *data;
>>> + void __iomem *mem;
>>>
>>> for_each_matching_node_and_match(np, omap_scrm_dt_match_table, &match) {
>>> data = (struct control_init_data *)match->data;
>>>
>>> - omap2_ctrl_base = of_iomap(np, 0);
>>> - if (!omap2_ctrl_base)
>>> + mem = of_iomap(np, 0);
>>> + if (!mem)
>>> return -ENOMEM;
>>>
>>> - omap2_ctrl_offset = data->offset;
>>> + if (data->index == TI_CLKM_CTRL) {
>>> + omap2_ctrl_base = mem;
>>> + omap2_ctrl_offset = data->offset;
>>> + }
>>> +
>>> + data->mem = mem;
>>> }
>>>
>>> return 0;
>>> @@ -713,7 +725,7 @@ int __init omap_control_init(void)
>>> } else {
>>> /* No scm_conf found, direct access */
>>> ret = omap2_clk_provider_init(np, data->index, NULL,
>>> - omap2_ctrl_base);
>>> + data->mem);
>>> if (ret)
>>> return ret;
>>> }
>>> diff --git a/include/linux/clk/ti.h b/include/linux/clk/ti.h
>>> index dc5164a..be25aa8 100644
>>> --- a/include/linux/clk/ti.h
>>> +++ b/include/linux/clk/ti.h
>>> @@ -195,6 +195,7 @@ enum {
>>> TI_CLKM_PRM,
>>> TI_CLKM_SCRM,
>>> TI_CLKM_CTRL,
>>> + TI_CLKM_CTRL_AUX,
>>> TI_CLKM_PLLSS,
>>> CLK_MAX_MEMMAPS
>>> };
>>
>
finally I found some time to apply your patches. Sorry for the long time.
Unfortunately, it does not work. Neither on omap5evm nor on our omap5 hardware.
I get no sound on the twl6040 - just white noise (which can be controlled in level through
amixer so it is created on the digital input side of the twl6040).
So I think your patch is missing a detail compared to my simple solution.
BR,
Nikolaus
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