From: Matthew Howell matthew.howell@sealevel.com
[ Upstream commit 5fdbe136ae19ab751daaa4d08d9a42f3e30d17f9 ]
Sealevel XR17V35X based devices are inoperable on kernel versions 4.11 and above due to a change in the GPIO preconfiguration introduced in commit 7dea8165f1d. This patch fixes this by preconfiguring the GPIO on Sealevel cards to the value (0x00) used prior to commit 7dea8165f1d
With GPIOs preconfigured as per commit 7dea8165f1d all ports on Sealevel XR17V35X based devices become stuck in high impedance mode, regardless of dip-switch or software configuration. This causes the device to become effectively unusable. This patch (in various forms) has been distributed to our customers and no issues related to it have been reported.
Fixes: 7dea8165f1d6 ("serial: exar: Preconfigure xr17v35x MPIOs as output") Signed-off-by: Matthew Howell matthew.howell@sealevel.com Link: https://lore.kernel.org/r/alpine.DEB.2.21.2007221605270.13247@tstest-Virtual... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/tty/serial/8250/8250_exar.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/8250/8250_exar.c b/drivers/tty/serial/8250/8250_exar.c index 899f36b59af79..ed81128bb42e0 100644 --- a/drivers/tty/serial/8250/8250_exar.c +++ b/drivers/tty/serial/8250/8250_exar.c @@ -229,7 +229,17 @@ static void setup_gpio(struct pci_dev *pcidev, u8 __iomem *p) * devices will export them as GPIOs, so we pre-configure them safely * as inputs. */ - u8 dir = pcidev->vendor == PCI_VENDOR_ID_EXAR ? 0xff : 0x00; + + u8 dir = 0x00; + + if ((pcidev->vendor == PCI_VENDOR_ID_EXAR) && + (pcidev->subsystem_vendor != PCI_VENDOR_ID_SEALEVEL)) { + // Configure GPIO as inputs for Commtech adapters + dir = 0xff; + } else { + // Configure GPIO as outputs for SeaLevel adapters + dir = 0x00; + }
writeb(0x00, p + UART_EXAR_MPIOINT_7_0); writeb(0x00, p + UART_EXAR_MPIOLVL_7_0);