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stm32h7/rcc: make VOS0 configurable from board.h

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It seems that over-drive is not required for ULPI but it can be a workaround solution for boards with poor signal integration.
Higher core voltage means faster clock signal edges, which may be sufficient to synchronize the high-speed clock and data on poorly designed boards.

Over-drive can be forced to a given state by adding define to the
board.h configuration file:

   #define STM32_VOS_OVERDRIVE 1 - force over-drive enabled,
   #define STM32_VOS_OVERDRIVE 0 - force over-drive disabled,
   #undef STM32_VOS_OVERDRIVE    - autoselect over-drive by the default RCC logic
This commit is contained in:
raiden00pl 2023-04-14 09:32:25 +02:00 committed by David Sidrane
parent 7671ed9615
commit 876b7a5e8e
1 changed files with 18 additions and 12 deletions
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30
arch/arm/src/stm32h7/stm32h7x3xx_rcc.c
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@ -104,24 +104,30 @@
#endif
/* Over-drive is supported only for Voltage output scale 1 mode.
* It is required when:
* - SYSCLK frequency is over 400 MHz,
* - external ULPI is selected
* It is required when SYSCLK frequency is over 400 MHz or it can be forced
* to a given state by adding define to the board.h configuration file:
*
* #define STM32_VOS_OVERDRIVE 1 - force over-drive enabled,
* #define STM32_VOS_OVERDRIVE 0 - force over-drive disabled,
* #undef STM32_VOS_OVERDRIVE - autoselect over-drive by logic below
*
* Boosting the core voltage can be a workaround solution to problems with
* poor board signal integration for high-speed digital interfaces like ULPI.
* Higher voltage means faster clock signal edges which may be sufficient to
* synchronise the high-speed clock and data.
*/
#if (STM32_PWR_VOS_SCALE == PWR_D3CR_VOS_SCALE_1)
# if (STM32_SYSCLK_FREQUENCY > 400000000)
# define STM32_VOS_OVERDRIVE 1
# elif defined(CONFIG_STM32H7_OTGHS_EXTERNAL_ULPI)
#ifndef STM32_VOS_OVERDRIVE
# if (STM32_PWR_VOS_SCALE == PWR_D3CR_VOS_SCALE_1) && \
(STM32_SYSCLK_FREQUENCY > 400000000)
# define STM32_VOS_OVERDRIVE 1
# else
# define STM32_VOS_OVERDRIVE 0
# endif
#endif
#ifdef CONFIG_STM32H7_OTGHS_EXTERNAL_ULPI
# if (STM32_PWR_VOS_SCALE != PWR_D3CR_VOS_SCALE_1)
# error external ULPI seems to work only with SCALE 0
#else
# if (STM32_VOS_OVERDRIVE == 1) && \
(STM32_PWR_VOS_SCALE != PWR_D3CR_VOS_SCALE_1)
# error Over-drive can be selected only when VOS1 is configured
# endif
#endif