| Message ID | 20200412180923.30774-1-mani@kernel.org (mailing list archive) |
|---|---|
| Headers | show |
| Series | Add software flow control support for STM32 UART | expand |
On Mon, Apr 13, 2020 at 7:06 AM <mani@kernel.org> wrote: > > From: Manivannan Sadhasivam <mani@kernel.org> > > Hello, > > This patchset adds software flow control support for STM32 UART controller. > 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 in order to > workaround that hardware bug and also to support the usecase of using only > Tx/Rx pins, this patchset adds software flow control support. > > This patchset has been validated w/ Stinger96 IoT-Box connected to Murata > WiFi-BT combo chip. > I think it's a mix of terminology or so. Looking into the patches I found that it's required to have GPIOs for SW flow control. No, SW flow control does not require any additional signals, except RxD/TxD. On top of that, it seems you adding mctrl-gpio functionality. Why can't you use that one? And thus no bindings needs to be updated. > Thanks, > Mani > > Manivannan Sadhasivam (2): > dt-bindings: serial: Add binding for software flow control in STM32 > UART > tty: serial: Add software flow control support for STM32 USART > > .../bindings/serial/st,stm32-uart.yaml | 15 +- > drivers/tty/serial/stm32-usart.c | 143 +++++++++++++++++- > drivers/tty/serial/stm32-usart.h | 4 + > 3 files changed, 155 insertions(+), 7 deletions(-) > > -- > 2.17.1 >
Hi Andy, On Mon, Apr 13, 2020 at 12:17:21PM +0300, Andy Shevchenko wrote: > On Mon, Apr 13, 2020 at 7:06 AM <mani@kernel.org> wrote: > > > > From: Manivannan Sadhasivam <mani@kernel.org> > > > > Hello, > > > > This patchset adds software flow control support for STM32 UART controller. > > 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 in order to > > workaround that hardware bug and also to support the usecase of using only > > Tx/Rx pins, this patchset adds software flow control support. > > > > This patchset has been validated w/ Stinger96 IoT-Box connected to Murata > > WiFi-BT combo chip. > > > > I think it's a mix of terminology or so. Looking into the patches I > found that it's required to have GPIOs for SW flow control. > No, SW flow control does not require any additional signals, except RxD/TxD. > Yikes. Yes I got it wrong. 'st,hw-flow-ctrl' property confused me :) > On top of that, it seems you adding mctrl-gpio functionality. Why > can't you use that one? And thus no bindings needs to be updated. > Sure. This looks feasible. Will submit a follow up patch. Thanks, Mani > > Thanks, > > Mani > > > > Manivannan Sadhasivam (2): > > dt-bindings: serial: Add binding for software flow control in STM32 > > UART > > tty: serial: Add software flow control support for STM32 USART > > > > .../bindings/serial/st,stm32-uart.yaml | 15 +- > > drivers/tty/serial/stm32-usart.c | 143 +++++++++++++++++- > > drivers/tty/serial/stm32-usart.h | 4 + > > 3 files changed, 155 insertions(+), 7 deletions(-) > > > > -- > > 2.17.1 > > > > > -- > With Best Regards, > Andy Shevchenko
From: Manivannan Sadhasivam <mani@kernel.org> Hello, This patchset adds software flow control support for STM32 UART controller. 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 in order to workaround that hardware bug and also to support the usecase of using only Tx/Rx pins, this patchset adds software flow control support. This patchset has been validated w/ Stinger96 IoT-Box connected to Murata WiFi-BT combo chip. Thanks, Mani Manivannan Sadhasivam (2): dt-bindings: serial: Add binding for software flow control in STM32 UART tty: serial: Add software flow control support for STM32 USART .../bindings/serial/st,stm32-uart.yaml | 15 +- drivers/tty/serial/stm32-usart.c | 143 +++++++++++++++++- drivers/tty/serial/stm32-usart.h | 4 + 3 files changed, 155 insertions(+), 7 deletions(-)