Re: [PATCH v6 09/10] clk: stm32: Fix ltdc's clock turn off by clk_disable_unused() after system enter shell

From: Dillon Min <dillon.minfei@gmail.com>
To: "gabriel.fernandez@foss.st.com" <gabriel.fernandez@foss.st.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>,
	mchehab+huawei@kernel.org,
	Hans Verkuil <hverkuil-cisco@xs4all.nl>,
	ezequiel@collabora.com, gnurou@gmail.com,
	Pi-Hsun Shih <pihsun@chromium.org>,
	Maxime Coquelin <mcoquelin.stm32@gmail.com>,
	Alexandre TORGUE <alexandre.torgue@foss.st.com>,
	Michael Turquette <mturquette@baylibre.com>,
	Stephen Boyd <sboyd@kernel.org>, Rob Herring <robh+dt@kernel.org>,
	gabriel.fernandez@st.com,
	Patrice CHOTARD <patrice.chotard@foss.st.com>,
	hugues.fruchet@foss.st.com,
	linux-media <linux-media@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-stm32@st-md-mailman.stormreply.com,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	linux-clk <linux-clk@vger.kernel.org>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
	<devicetree@vger.kernel.org>
Subject: Re: [PATCH v6 09/10] clk: stm32: Fix ltdc's clock turn off by clk_disable_unused() after system enter shell
Date: Fri, 22 Oct 2021 17:14:32 +0800	[thread overview]
Message-ID: <CAL9mu0LUs0iwn2NUaUrbDjDGkB8dahdW+86RSeVJPpaP=V8f6A@mail.gmail.com> (raw)
In-Reply-To: <b43699a6-dc53-3fcd-6cc9-6b05025cad96@foss.st.com>

Hi Gabriel

Thanks for the quick response.

Best Regards
Dillon

On Fri, 22 Oct 2021 at 17:10, gabriel.fernandez@foss.st.com
<gabriel.fernandez@foss.st.com> wrote:
>
> Hi Dillon,
>
> You can add my Acked-by: Gabriel Fernandez <gabriel.fernandez@foss.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@gmail.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@kernel.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@gmail.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
> >>