[RESEND PATCH v4] clk: stm32f4: fix post divisor setup for I2S/SAI PLLs

[Dario Binacchi]

Hi Dillon,

> Il 28/07/2021 12:03 Dillon Hua <dillonhua at gmail.com> ha scritto:
> 
>  
> Hi Dario,
> 
> I have a similar patch [1] submitted last year.
> Unfortunately, it did not get accepted by the maintainer.
> 
> Just a reminder here for you, should remove
> 
> { STM32F4_RCC_APB2ENR, 26, "ltdc", "apb2_div" },

Thank you for your suggestion.
While testing the patch on the stm32f469-disco board I didn't
notice the white screen issue. I'll try to run the tests again. 
I will let you know.

Thanks and regards,
Dario

> 
> from stm32{f429, f469, f746, f769}_gates[]; or else
> run into white screen after the kernel enters the console.
> 
> This patch was verified by Patrice Chotard, you can
> find  the history from [2].
> 
> Hope you can help to submit a patch to include [2], thanks.
> 
> [1]
> https://lore.kernel.org/linux-arm-kernel/1590564453-24499-7-git-send-email-dillon.minfei@gmail.com/
> https://lore.kernel.org/linux-arm-kernel/1590564453-24499-6-git-send-email-dillon.minfei@gmail.com/
> 
> resend this year:
> https://lore.kernel.org/lkml/1590378348-8115-6-git-send-email-dillon.minfei@gmail.com/
> 
> [2]
> https://lore.kernel.org/lkml/6915fa2a-e211-476f-8317-6825e280c322@foss.st.com/
> 
> Thanks
> Best Regards
> 
> Dillon
> 
> On Mon, Jul 26, 2021 at 12:08 AM Dario Binacchi <dariobin at libero.it> wrote:
> >
> > Enabling the framebuffer leads to a system hang. Running, as a debug
> > hack, the store_pan() function in drivers/video/fbdev/core/fbsysfs.c
> > without taking the console_lock, allows to see the crash backtrace on
> > the serial line.
> >
> > ~ # echo 0 0 > /sys/class/graphics/fb0/pan
> >
> > [    9.719414] Unhandled exception: IPSR = 00000005 LR = fffffff1
> > [    9.726937] CPU: 0 PID: 49 Comm: sh Not tainted 5.13.0-rc5 #9
> > [    9.733008] Hardware name: STM32 (Device Tree Support)
> > [    9.738296] PC is at clk_gate_is_enabled+0x0/0x28
> > [    9.743426] LR is at stm32f4_pll_div_set_rate+0xf/0x38
> > [    9.748857] pc : [<0011e4be>]    lr : [<0011f9e3>]    psr: 0100000b
> > [    9.755373] sp : 00bc7be0  ip : 00000000  fp : 001f3ac4
> > [    9.760812] r10: 002610d0  r9 : 01efe920  r8 : 00540560
> > [    9.766269] r7 : 02e7ddb0  r6 : 0173eed8  r5 : 00000000  r4 : 004027c0
> > [    9.773081] r3 : 0011e4bf  r2 : 02e7ddb0  r1 : 0173eed8  r0 : 1d3267b8
> > [    9.779911] xPSR: 0100000b
> > [    9.782719] CPU: 0 PID: 49 Comm: sh Not tainted 5.13.0-rc5 #9
> > [    9.788791] Hardware name: STM32 (Device Tree Support)
> > [    9.794120] [<0000afa1>] (unwind_backtrace) from [<0000a33f>] (show_stack+0xb/0xc)
> > [    9.802421] [<0000a33f>] (show_stack) from [<0000a8df>] (__invalid_entry+0x4b/0x4c)
> >
> > The `pll_num' field in the post_div_data configuration contained a wrong
> > value which also referenced an uninitialized hardware clock when
> > clk_register_pll_div() was called.
> >
> > Fixes: 517633ef630e ("clk: stm32f4: Add post divisor for I2S & SAI PLLs")
> > Signed-off-by: Dario Binacchi <dariobin at libero.it>
> > Reviewed-by: Gabriel Fernandez <gabriel.fernandez at st.com>
> >
> > ---
> > I added Gabriel Fernandez's 'Reviewed-by' tag as requested by himself
> > 15 days ago at https://lore.kernel.org/patchwork/patch/1450964/.
> >
> > Changes in v4:
> > - Really add Gabriel Fernandez 'Reviewed-by' tag. In version 3 I forgot
> >   to add the tag.
> >
> > Changes in v3:
> > - Add Gabriel Fernandez 'Reviewed-by' tag.
> >
> > Changes in v2:
> > - Change  'u8 pll_num' from 'stm32f4_pll_post_div_data' structure into
> >   'int pll_idx'.
> >
> >  drivers/clk/clk-stm32f4.c | 10 +++++-----
> >  1 file changed, 5 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/clk/clk-stm32f4.c b/drivers/clk/clk-stm32f4.c
> > index 18117ce5ff85..5c75e3d906c2 100644
> > --- a/drivers/clk/clk-stm32f4.c
> > +++ b/drivers/clk/clk-stm32f4.c
> > @@ -526,7 +526,7 @@ struct stm32f4_pll {
> >
> >  struct stm32f4_pll_post_div_data {
> >         int idx;
> > -       u8 pll_num;
> > +       int pll_idx;
> >         const char *name;
> >         const char *parent;
> >         u8 flag;
> > @@ -557,13 +557,13 @@ 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 },
> >  };
> >
> > @@ -1774,7 +1774,7 @@ static void __init stm32f4_rcc_init(struct device_node *np)
> >                                 post_div->width,
> >                                 post_div->flag_div,
> >                                 post_div->div_table,
> > -                               clks[post_div->pll_num],
> > +                               clks[post_div->pll_idx],
> >                                 &stm32f4_clk_lock);
> >
> >                 if (post_div->idx != NO_IDX)
> > --
> > 2.17.1
> >