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References: <1569411888-98116-1-git-send-email-jian.hu@amlogic.com> <1569411888-98116-3-git-send-email-jian.hu@amlogic.com> <20190925131232.4751020640@mail.kernel.org> <8351489a-f91e-be08-7fcc-e2a90c6e87f0@amlogic.com>
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From:   Jerome Brunet <jbrunet@baylibre.com>
To:     Jian Hu <jian.hu@amlogic.com>
Cc:     Stephen Boyd <sboyd@kernel.org>,
        Jerome Brunet <jbrunet@baylibre.com>,
        Neil Armstrong <narmstrong@baylibre.com>,
        Rob Herring <robh@kernel.org>,
        Jianxin Pan <jianxin.pan@amlogic.com>,
        devicetree@vger.kernel.org,
        Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
        Kevin Hilman <khilman@baylibre.com>,
        Michael Turquette <mturquette@baylibre.com>,
        linux-kernel@vger.kernel.org,
        Qiufang Dai <qiufang.dai@amlogic.com>,
        linux-amlogic@lists.infradead.org, linux-clk@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 2/2] clk: meson: a1: add support for Amlogic A1 clock driver
In-reply-to: <8351489a-f91e-be08-7fcc-e2a90c6e87f0@amlogic.com>
Date:   Fri, 27 Sep 2019 14:56:23 +0200
Message-ID: <1jk19t28zs.fsf@starbuckisacylon.baylibre.com>
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On Fri 27 Sep 2019 at 05:11, Jian Hu <jian.hu@amlogic.com> wrote:

> Hi, Stephen
>
> Thank you for review
>
> On 2019/9/25 21:12, Stephen Boyd wrote:
>> Quoting Jian Hu (2019-09-25 04:44:48)
>>> The Amlogic A1 clock includes three parts:
>>> peripheral clocks, pll clocks, CPU clocks.
>>> sys pll and CPU clocks will be sent in next patch.
>>>
>>> Unlike the previous series, there is no EE/AO domain
>>> in A1 CLK controllers.
>>>
>>> Signed-off-by: Jian Hu <jian.hu@amlogic.com>
>>> Signed-off-by: Jianxin Pan <jianxin.pan@amlogic.com>
>>
>> This second name didn't send the patch. Please follow the signoff
>> procedures documented in Documentation/process/submitting-patches.rst
>>
>>> diff --git a/arch/arm64/Kconfig.platforms b/arch/arm64/Kconfig.platforms
>>> index 16d7614..a48f67d 100644
>>> --- a/arch/arm64/Kconfig.platforms
>>> +++ b/arch/arm64/Kconfig.platforms
>>> @@ -138,6 +138,7 @@ config ARCH_MESON
>>>          select COMMON_CLK_AXG
>>>          select COMMON_CLK_G12A
>>>          select MESON_IRQ_GPIO
>>> +       select COMMON_CLK_A1
>>
>> Sort?
> ok, I will put it behind COMMON_CLK_AXG
>>
>>>          help
>>>            This enables support for the arm64 based Amlogic SoCs
>>>            such as the s905, S905X/D, S912, A113X/D or S905X/D2
>>> diff --git a/drivers/clk/meson/Kconfig b/drivers/clk/meson/Kconfig
>>> index dabeb43..e6cb4c3 100644
>>> --- a/drivers/clk/meson/Kconfig
>>> +++ b/drivers/clk/meson/Kconfig
>>> @@ -107,3 +107,13 @@ config COMMON_CLK_G12A
>>>          help
>>>            Support for the clock controller on Amlogic S905D2, S905X2 and S905Y2
>>>            devices, aka g12a. Say Y if you want peripherals to work.
>>> +
>>> +config COMMON_CLK_A1
>>
>> Probably should be placed somewhere alphabetically in this file?
> ok, I will put it behind COMMON_CLK_AXG_AUDIO
>>
>>> +       bool
>>> +       depends on ARCH_MESON
>>> +       select COMMON_CLK_MESON_REGMAP
>>> +       select COMMON_CLK_MESON_DUALDIV
>>> +       select COMMON_CLK_MESON_PLL
>>> +       help
>>> +         Support for the clock controller on Amlogic A113L device,
>>> +         aka a1. Say Y if you want peripherals to work.
>>> diff --git a/drivers/clk/meson/Makefile b/drivers/clk/meson/Makefile
>>> index 3939f21..6be3a8f 100644
>>> --- a/drivers/clk/meson/Makefile
>>> +++ b/drivers/clk/meson/Makefile
>>> @@ -19,3 +19,4 @@ obj-$(CONFIG_COMMON_CLK_AXG_AUDIO) += axg-audio.o
>>>   obj-$(CONFIG_COMMON_CLK_GXBB) += gxbb.o gxbb-aoclk.o
>>>   obj-$(CONFIG_COMMON_CLK_G12A) += g12a.o g12a-aoclk.o
>>>   obj-$(CONFIG_COMMON_CLK_MESON8B) += meson8b.o
>>> +obj-$(CONFIG_COMMON_CLK_A1) += a1.o
>>
>> I would guess this should be sorted on Kconfig name in this file?
> ok, I will put it behind COMMON_CLK_AXG_AUDIO
>>
>>> diff --git a/drivers/clk/meson/a1.c b/drivers/clk/meson/a1.c
>>> new file mode 100644
>>> index 0000000..26edae0f
>>> --- /dev/null
>>> +++ b/drivers/clk/meson/a1.c
>>> @@ -0,0 +1,2617 @@
>>> +// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
>>> +/*
>>> + * Copyright (c) 2019 Amlogic, Inc. All rights reserved.
>>> + */
>>> +
>>> +#include <linux/clk-provider.h>
>>> +#include <linux/init.h>
>>> +#include <linux/of_device.h>
>>> +#include <linux/platform_device.h>
>>> +#include <linux/of_address.h>
>>> +#include "clk-mpll.h"
>>> +#include "clk-pll.h"
>>> +#include "clk-regmap.h"
>>> +#include "vid-pll-div.h"
>>> +#include "clk-dualdiv.h"
>>> +#include "meson-eeclk.h"
>>> +#include "a1.h"
>>> +
>> [...]
>>> +
>>> +/*
>>> + * The Meson A1 HIFI PLL is 614.4M, it requires
>>> + * a strict register sequence to enable the PLL.
>>> + * set meson_clk_pcie_pll_ops as its ops
>>
>> Please remove this last line as it's obvious from the code what ops are
>> used.
>>
> ok, I will remove it.
>>> + */
>>> +static struct clk_regmap a1_hifi_pll = {
>>> +       .data = &(struct meson_clk_pll_data){
>>> +               .en = {
>>> +                       .reg_off = ANACTRL_HIFIPLL_CTRL0,
>>> +                       .shift   = 28,
>>> +                       .width   = 1,
>>> +               },
>>> +               .m = {
>>> +                       .reg_off = ANACTRL_HIFIPLL_CTRL0,
>>> +                       .shift   = 0,
>>> +                       .width   = 8,
>>> +               },
>>> +               .n = {
>>> +                       .reg_off = ANACTRL_HIFIPLL_CTRL0,
>>> +                       .shift   = 10,
>>> +                       .width   = 5,
>>> +               },
>>> +               .frac = {
>>> +                       .reg_off = ANACTRL_HIFIPLL_CTRL1,
>>> +                       .shift   = 0,
>>> +                       .width   = 19,
>>> +               },
>>> +               .l = {
>>> +                       .reg_off = ANACTRL_HIFIPLL_STS,
>>> +                       .shift   = 31,
>>> +                       .width   = 1,
>>> +               },
>>> +               .table = a1_hifi_pll_params_table,
>>> +               .init_regs = a1_hifi_init_regs,
>>> +               .init_count = ARRAY_SIZE(a1_hifi_init_regs),
>>> +       },
>>> +       .hw.init = &(struct clk_init_data){
>>> +               .name = "hifi_pll",
>>> +               .ops = &meson_clk_pcie_pll_ops,
>>> +               .parent_hws = (const struct clk_hw *[]) {
>>> +                       &a1_xtal_hifipll.hw
>>> +               },
>>> +               .num_parents = 1,
>>> +       },
>>> +};
>>> +
>> [..]
>>> +
>>> +static struct clk_regmap a1_fclk_div2 = {
>>> +       .data = &(struct clk_regmap_gate_data){
>>> +               .offset = ANACTRL_FIXPLL_CTRL0,
>>> +               .bit_idx = 21,
>>> +       },
>>> +       .hw.init = &(struct clk_init_data){
>>> +               .name = "fclk_div2",
>>> +               .ops = &clk_regmap_gate_ops,
>>> +               .parent_hws = (const struct clk_hw *[]) {
>>> +                       &a1_fclk_div2_div.hw
>>> +               },
>>> +               .num_parents = 1,
>>> +               /*
>>> +                * add CLK_IS_CRITICAL flag to avoid being disabled by clk core
>>> +                * or its children clocks.
>>
>> This comment is useless. Please replace it with an actual reason for
>> keeping the clk on instead of describing what the flag does.
>>
> ok, The actual reason is it should not change at runtime.

Yeah, from the flag we understand that you want to keep this on. What we
are after is why ? What device is using this clock and cannot tolerate
this gate to turn off ?

This is important and this is kind of comment we are after.
These flag should be viewed as "mid term work around". In the end, there
should be a driver for your device which claims the clock and properly
manage it

>>> +                */
>>> +               .flags = CLK_IS_CRITICAL,
>>> +       },
>>> +};
>>> +
>> [..]
>>> +static struct clk_regmap a1_dmc = {
>>> +       .data = &(struct clk_regmap_gate_data){
>>> +               .offset = DMC_CLK_CTRL,
>>> +               .bit_idx = 8,
>>> +       },
>>> +       .hw.init = &(struct clk_init_data) {
>>> +               .name = "dmc",
>>> +               .ops = &clk_regmap_gate_ops,
>>> +               .parent_hws = (const struct clk_hw *[]) {
>>> +                       &a1_dmc_sel2.hw
>>> +               },
>>> +               .num_parents = 1,
>>> +               /*
>>> +                * add CLK_IGNORE_UNUSED to avoid hangup
>>> +                * DDR clock should not change at runtime
>>> +                */
>>> +               .flags = CLK_SET_RATE_PARENT | CLK_IGNORE_UNUSED,
>>
>> So not CLK_IS_CRITICAL?
> Yes, CLK_IS_CRITICAL is better, I will change it.

Same comment as above.

>>
>>> +       },
>>> +};
>>> +
>> [...]
>>> +
>>> +/*
>>> + * cpu clock register base address is 0xfd000080
>>> + */
>>> +static struct clk_regmap *const a1_cpu_clk_regmaps[] = {
>>> +       /* TODO */
>>
>> Can it be done?
> I plan to compelte cpu clock with the DVFS verified. And  Some peripheral
> devices rely on this patch to send. I prefer to do it in the next patch.
>>
>>> +};
>>
>> .
>>