linux-kernel - Re: [PATCH v6 09/10] clk: stm32: Fix ltdc's clock turn off by clk_disable

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Date:   Fri, 22 Oct 2021 11:10:14 +0200
From:   "gabriel.fernandez@...s.st.com" <gabriel.fernandez@...s.st.com>
To:     Dillon Min <dillon.minfei@...il.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        <mchehab+huawei@...nel.org>,
        Hans Verkuil <hverkuil-cisco@...all.nl>,
        <ezequiel@...labora.com>, <gnurou@...il.com>,
        Pi-Hsun Shih <pihsun@...omium.org>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre TORGUE <alexandre.torgue@...s.st.com>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Rob Herring <robh+dt@...nel.org>, <gabriel.fernandez@...com>
CC:     Patrice CHOTARD <patrice.chotard@...s.st.com>,
        <hugues.fruchet@...s.st.com>,
        linux-media <linux-media@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        linux-clk <linux-clk@...r.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>
Subject: Re: [PATCH v6 09/10] clk: stm32: Fix ltdc's clock turn off by
 clk_disable_unused() after system enter shell

Hi Dillon,

You can add my Acked-by: Gabriel Fernandez <gabriel.fernandez@...s.st.com>

Best Regards
Gabriel

On 10/22/21 9:25 AM, Dillon Min wrote:
> Hi Gabriel
> 
> I guess you are the maintainer of stm32 clk subsystem from [1], Could
> you help to review this patch, just give a brief of the history:
> 
> - this patch was acked by Stephen Boyd at [2].
> - reviewed by Patrice Chotard at [3].
> 
> Without this patch , the kernel will turn off ltdc's clk after the
> system reach shell.
> 
> [1] https://lore.kernel.org/lkml/AM8PR10MB4785545DC980090C1E7D66B281009@AM8PR10MB4785.EURPRD10.PROD.OUTLOOK.COM/
> 
> [2] https://lore.kernel.org/linux-arm-kernel/159056850835.88029.9264848839121822798@swboyd.mtv.corp.google.com/
> 
> [3] https://lore.kernel.org/lkml/6915fa2a-e211-476f-8317-6825e280c322@foss.st.com/#t
> 
> Best Regards
> Dillon
> 
> On Tue, 19 Oct 2021 at 16:44, Dillon Min <dillon.minfei@...il.com> wrote:
>>
>> stm32's clk driver register two ltdc gate clk to clk core by
>> clk_hw_register_gate() and clk_hw_register_composite()
>>
>> first: 'stm32f429_gates[]', clk name is 'ltdc', which no user to use.
>> second: 'stm32f429_aux_clk[]', clk name is 'lcd-tft', used by ltdc driver
>>
>> both of them point to the same offset of stm32's RCC register. after
>> kernel enter console, clk core turn off ltdc's clk as 'stm32f429_gates[]'
>> is no one to use. but, actually 'stm32f429_aux_clk[]' is in use.
>>
>> stm32f469/746/769 have the same issue, fix it.
>>
>> Fixes: daf2d117cbca ("clk: stm32f4: Add lcd-tft clock")
>> Acked-by: Stephen Boyd <sboyd@...nel.org>
>> Link: https://lore.kernel.org/linux-arm-kernel/1590564453-24499-7-git-send-email-dillon.minfei@gmail.com/
>> Link: https://lore.kernel.org/lkml/CAPTRvHkf0cK_4ZidM17rPo99gWDmxgqFt4CDUjqFFwkOeQeFDg@mail.gmail.com/
>> Signed-off-by: Dillon Min <dillon.minfei@...il.com>
>> ---
>> v6: no change.
>>
>>   drivers/clk/clk-stm32f4.c | 4 ----
>>   1 file changed, 4 deletions(-)
>>
>> diff --git a/drivers/clk/clk-stm32f4.c b/drivers/clk/clk-stm32f4.c
>> index af46176ad053..473dfe632cc5 100644
>> --- a/drivers/clk/clk-stm32f4.c
>> +++ b/drivers/clk/clk-stm32f4.c
>> @@ -129,7 +129,6 @@ static const struct stm32f4_gate_data stm32f429_gates[] __initconst = {
>>          { STM32F4_RCC_APB2ENR, 20,      "spi5",         "apb2_div" },
>>          { STM32F4_RCC_APB2ENR, 21,      "spi6",         "apb2_div" },
>>          { STM32F4_RCC_APB2ENR, 22,      "sai1",         "apb2_div" },
>> -       { STM32F4_RCC_APB2ENR, 26,      "ltdc",         "apb2_div" },
>>   };
>>
>>   static const struct stm32f4_gate_data stm32f469_gates[] __initconst = {
>> @@ -211,7 +210,6 @@ static const struct stm32f4_gate_data stm32f469_gates[] __initconst = {
>>          { STM32F4_RCC_APB2ENR, 20,      "spi5",         "apb2_div" },
>>          { STM32F4_RCC_APB2ENR, 21,      "spi6",         "apb2_div" },
>>          { STM32F4_RCC_APB2ENR, 22,      "sai1",         "apb2_div" },
>> -       { STM32F4_RCC_APB2ENR, 26,      "ltdc",         "apb2_div" },
>>   };
>>
>>   static const struct stm32f4_gate_data stm32f746_gates[] __initconst = {
>> @@ -286,7 +284,6 @@ static const struct stm32f4_gate_data stm32f746_gates[] __initconst = {
>>          { STM32F4_RCC_APB2ENR, 21,      "spi6",         "apb2_div" },
>>          { STM32F4_RCC_APB2ENR, 22,      "sai1",         "apb2_div" },
>>          { STM32F4_RCC_APB2ENR, 23,      "sai2",         "apb2_div" },
>> -       { STM32F4_RCC_APB2ENR, 26,      "ltdc",         "apb2_div" },
>>   };
>>
>>   static const struct stm32f4_gate_data stm32f769_gates[] __initconst = {
>> @@ -364,7 +361,6 @@ static const struct stm32f4_gate_data stm32f769_gates[] __initconst = {
>>          { STM32F4_RCC_APB2ENR, 21,      "spi6",         "apb2_div" },
>>          { STM32F4_RCC_APB2ENR, 22,      "sai1",         "apb2_div" },
>>          { STM32F4_RCC_APB2ENR, 23,      "sai2",         "apb2_div" },
>> -       { STM32F4_RCC_APB2ENR, 26,      "ltdc",         "apb2_div" },
>>          { STM32F4_RCC_APB2ENR, 30,      "mdio",         "apb2_div" },
>>   };
>>
>> --
>> 2.7.4
>>