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[v2,0/2] Add CTS/RTS gpio support to STM32 UART

Message ID 20200416175729.5550-1-mani@kernel.org
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Series Add CTS/RTS gpio support to STM32 UART | expand

Message

Manivannan Sadhasivam April 16, 2020, 5:57 p.m. UTC 
From: Manivannan Sadhasivam <mani@kernel.org>

Hello,

This patchset adds CTS/RTS gpio support to STM32 UART controller.
Eventhough the UART controller supports using dedicated CTS/RTS gpios,
sometimes we need to use different set of gpios for flow control.

This is necessary for the upcoming STM32MP1 based board called Stinger96
IoT-Box. On that board, a bluetooth chip is connected to one of the UART
controller but the CTS/RTS lines got swapped mistakenly. So this patchset
serves as a workaround for that hardware bug and also supports the
usecase of using any gpio for CTS/RTS functionality. As per the sugggestion
provided by Andy for v1, I've now switched to mctrl_gpio driver.

This patchset has been validated with Stinger96 IoT-Box connected to Murata
WiFi-BT combo chip.

Thanks,
Mani

Changes in v2:

As per the review by Andy:

* Switched to mctrl_gpio driver instead of using custom CTS/RTS
  implementation
* Removed the use of software flow control terminology.

Manivannan Sadhasivam (2):
  tty: serial: Add modem control gpio support for STM32 UART
  dt-bindings: serial: Document CTS/RTS gpios in STM32 UART

 .../bindings/serial/st,stm32-uart.yaml        | 14 ++++++
 drivers/tty/serial/Kconfig                    |  1 +
 drivers/tty/serial/stm32-usart.c              | 43 ++++++++++++++++++-
 drivers/tty/serial/stm32-usart.h              |  1 +
 4 files changed, 58 insertions(+), 1 deletion(-)