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

"gabriel.fernandez@xxxxxxxxxxx" <gabriel.fernandez@xxxxxxxxxxx> · Fri, 22 Oct 2021 11:10:14 +0200

Hi Dillon,

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

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@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/

[2] https://lore.kernel.org/linux-arm-kernel/159056850835.88029.9264848839121822798@xxxxxxxxxxxxxxxxxxxxxxxxxx/

[3] https://lore.kernel.org/lkml/6915fa2a-e211-476f-8317-6825e280c322@xxxxxxxxxxx/#t

Best Regards
Dillon

On Tue, 19 Oct 2021 at 16:44, Dillon Min <dillon.minfei@xxxxxxxxx> 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@xxxxxxxxxx>
Link: https://lore.kernel.org/linux-arm-kernel/1590564453-24499-7-git-send-email-dillon.minfei@xxxxxxxxx/
Link: https://lore.kernel.org/lkml/CAPTRvHkf0cK_4ZidM17rPo99gWDmxgqFt4CDUjqFFwkOeQeFDg@xxxxxxxxxxxxxx/
Signed-off-by: Dillon Min <dillon.minfei@xxxxxxxxx>
---
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







