[PATCH v4 1/9] serial: exar: Leave MPIOs as output for Commtech adapters
From: Jan Kiszka <jan.kiszka@siemens.com>
Date: 2017-05-30 07:01:54
Also in:
linux-gpio, lkml
Subsystem:
8250/16?50 (and clone uarts) serial driver, the rest, tty layer and serial drivers · Maintainers:
Greg Kroah-Hartman, Linus Torvalds, Jiri Slaby
Commtech adapters apparently need the original setting as outputs, see https://marc.info/?l=linux-gpio&m=149557425201323&w=2. Account for that. Fixes: 7dea8165f1d6 ("serial: exar: Preconfigure xr17v35x MPIOs as output") Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> --- drivers/tty/serial/8250/8250_exar.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_exar.c b/drivers/tty/serial/8250/8250_exar.c
index b4fa585156c7..8984e8b2d524 100644
--- a/drivers/tty/serial/8250/8250_exar.c
+++ b/drivers/tty/serial/8250/8250_exar.c@@ -171,19 +171,26 @@ pci_xr17c154_setup(struct exar8250 *priv, struct pci_dev *pcidev, return default_setup(priv, pcidev, idx, offset, port); } -static void setup_gpio(u8 __iomem *p) +static void setup_gpio(struct pci_dev *pcidev, u8 __iomem *p) { + /* + * The Commtech adapters required the MPIOs to be driven low. The Exar + * devices will export them as GPIOs, so we pre-configure them safely + * as inputs. + */ + u8 dir = pcidev->vendor == PCI_VENDOR_ID_EXAR ? 0xff : 0x00; + writeb(0x00, p + UART_EXAR_MPIOINT_7_0); writeb(0x00, p + UART_EXAR_MPIOLVL_7_0); writeb(0x00, p + UART_EXAR_MPIO3T_7_0); writeb(0x00, p + UART_EXAR_MPIOINV_7_0); - writeb(0xff, p + UART_EXAR_MPIOSEL_7_0); + writeb(dir, p + UART_EXAR_MPIOSEL_7_0); writeb(0x00, p + UART_EXAR_MPIOOD_7_0); writeb(0x00, p + UART_EXAR_MPIOINT_15_8); writeb(0x00, p + UART_EXAR_MPIOLVL_15_8); writeb(0x00, p + UART_EXAR_MPIO3T_15_8); writeb(0x00, p + UART_EXAR_MPIOINV_15_8); - writeb(0xff, p + UART_EXAR_MPIOSEL_15_8); + writeb(dir, p + UART_EXAR_MPIOSEL_15_8); writeb(0x00, p + UART_EXAR_MPIOOD_15_8); }
@@ -236,7 +243,7 @@ pci_xr17v35x_setup(struct exar8250 *priv, struct pci_dev *pcidev, if (idx == 0) { /* Setup Multipurpose Input/Output pins. */ - setup_gpio(p); + setup_gpio(pcidev, p); port->port.private_data = xr17v35x_register_gpio(pcidev); }
--
2.12.3