[PATCH 3/7] clk: stm32: Fix ltdc's clock turn off by clk_disable_unused() after kernel startup

[Dillon Min]

Hi Hans,

On Thu, Jun 17, 2021 at 5:57 PM Hans Verkuil <hverkuil-cisco at xs4all.nl> wrote:
>
> On 20/05/2021 13:05, dillon.minfei at gmail.com wrote:
> > From: Dillon Min <dillon.minfei at gmail.com>
> >
> > 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.
> >
> > Fixes: daf2d117cbca ("clk: stm32f4: Add lcd-tft clock")
> > Signed-off-by: Dillon Min <dillon.minfei at gmail.com>
> > Acked-by: Stephen Boyd <sboyd at kernel.org>
> > Link: https://lore.kernel.org/linux-arm-kernel/1590564453-24499-7-git-send-email-dillon.minfei@gmail.com/
>
> For my understanding: this patch is going/has already gone in via a different
> subsystem, right? And I should skip it when adding this driver to the media subsystem?

Yes, Just ignore this patch please.

It's only to make st's engineer easier to verify the dma2d driver,
since the board's lcd panel depends on this patch to work

stm32f469-disco board :
https://www.st.com/content/st_com/en/products/evaluation-tools/product-evaluation-tools/mcu-mpu-eval-tools/stm32-mcu-mpu-eval-tools/stm32-discovery-kits/32f469idiscovery.html

Thanks
Best Regards

Dillon

>
> Regards,
>
>         Hans
>
> > ---
> >
> > This patch was submitted in
> > https://lore.kernel.org/lkml/1620990152-19255-1-git-send-email-dillon.minfei@gmail.com/
> >
> >  drivers/clk/clk-stm32f4.c | 7 +++----
> >  1 file changed, 3 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/clk/clk-stm32f4.c b/drivers/clk/clk-stm32f4.c
> > index 18117ce5ff85..b6ab8c3a7994 100644
> > --- a/drivers/clk/clk-stm32f4.c
> > +++ b/drivers/clk/clk-stm32f4.c
> > @@ -211,7 +211,6 @@ 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 = {
> > @@ -557,13 +556,13 @@ static const struct clk_div_table post_divr_table[] = {
> >
> >  #define MAX_POST_DIV 3
> >  static const struct stm32f4_pll_post_div_data  post_div_data[MAX_POST_DIV] = {
> > -     { CLK_I2SQ_PDIV, PLL_I2S, "plli2s-q-div", "plli2s-q",
> > +     { CLK_I2SQ_PDIV, PLL_VCO_I2S, "plli2s-q-div", "plli2s-q",
> >               CLK_SET_RATE_PARENT, STM32F4_RCC_DCKCFGR, 0, 5, 0, NULL},
> >
> > -     { CLK_SAIQ_PDIV, PLL_SAI, "pllsai-q-div", "pllsai-q",
> > +     { CLK_SAIQ_PDIV, PLL_VCO_SAI, "pllsai-q-div", "pllsai-q",
> >               CLK_SET_RATE_PARENT, STM32F4_RCC_DCKCFGR, 8, 5, 0, NULL },
> >
> > -     { NO_IDX, PLL_SAI, "pllsai-r-div", "pllsai-r", CLK_SET_RATE_PARENT,
> > +     { NO_IDX, PLL_VCO_SAI, "pllsai-r-div", "pllsai-r", CLK_SET_RATE_PARENT,
> >               STM32F4_RCC_DCKCFGR, 16, 2, 0, post_divr_table },
> >  };
> >
> >
>