Re: imx: RS-485 problems during TX, maybe DMA related
From: Fabio Estevam <festevam@gmail.com>
Date: 2017-01-07 14:57:22
Also in:
linux-arm-kernel, lkml
From: Fabio Estevam <festevam@gmail.com>
Date: 2017-01-07 14:57:22
Also in:
linux-arm-kernel, lkml
Hi Clemens, On Sat, Jan 7, 2017 at 11:45 AM, Clemens Gruber [off-list ref] wrote:
It should work like this, I don't think using an extra GPIO is necessary.
The MX6QDL_PAD_CSI0_DAT16__UART4_CTS_B option is only valid in dte mode. If I pass 'fsl,dte-mode' then I can see this pin toggling. (rx, tx would not work as expected). In the default dce mode I can see UART4_CTS_B pin toggling when I monitor CSI0_DAT17 pin and configure it as: MX6QDL_PAD_CSI0_DAT17__UART4_CTS_B ,but unfortunately this pin does not go to the TXEN pin of the RS485 transceiver. So this means that with the hardware I have access to my only alternative is to set MX6QDL_PAD_CSI0_DAT16__GPIO6_IO02.
quoted
So I was never able to observe the DE pin toggling correctly.But did you set SER_RS485_RX_DURING_TX in your flags? This is counter intuitive, but I observed that it would not work otherwise.
Yes, I have also tried when I read your email, but did not help on my case. Thanks, Fabio Estevam