serial: exar: Add support for IOT2040 device

[linux.git] / drivers / tty / serial / 8250 / 8250_exar.c

diff --git a/drivers/tty/serial/8250/8250_exar.c b/drivers/tty/serial/8250/8250_exar.c
index 9931e26ca0616f55a8bd48ffe715c635879c634f..b105f4cb51aae33c7211b5d093a1cf1f988f121c 100644 (file)
--- a/drivers/tty/serial/8250/8250_exar.c
+++ b/drivers/tty/serial/8250/8250_exar.c
@@ -10,6 +10,7 @@
  * the Free Software Foundation; either version 2 of the License.
  */
 #include <linux/acpi.h>
+#include <linux/dmi.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
@@ -62,6 +63,43 @@
 #define UART_EXAR_MPIOSEL_15_8 0x99    /* MPIOSEL[15:8] */
 #define UART_EXAR_MPIOOD_15_8  0x9a    /* MPIOOD[15:8] */
 
+#define UART_EXAR_RS485_DLY(x) ((x) << 4)
+
+/*
+ * IOT2040 MPIO wiring semantics:
+ *
+ * MPIO                Port    Function
+ * ----                ----    --------
+ * 0           2       Mode bit 0
+ * 1           2       Mode bit 1
+ * 2           2       Terminate bus
+ * 3           -       <reserved>
+ * 4           3       Mode bit 0
+ * 5           3       Mode bit 1
+ * 6           3       Terminate bus
+ * 7           -       <reserved>
+ * 8           2       Enable
+ * 9           3       Enable
+ * 10          -       Red LED
+ * 11..15      -       <unused>
+ */
+
+/* IOT2040 MPIOs 0..7 */
+#define IOT2040_UART_MODE_RS232                0x01
+#define IOT2040_UART_MODE_RS485                0x02
+#define IOT2040_UART_MODE_RS422                0x03
+#define IOT2040_UART_TERMINATE_BUS     0x04
+
+#define IOT2040_UART1_MASK             0x0f
+#define IOT2040_UART2_SHIFT            4
+
+#define IOT2040_UARTS_DEFAULT_MODE     0x11    /* both RS232 */
+#define IOT2040_UARTS_GPIO_LO_MODE     0x88    /* reserved pins as input */
+
+/* IOT2040 MPIOs 8..15 */
+#define IOT2040_UARTS_ENABLE           0x03
+#define IOT2040_UARTS_GPIO_HI_MODE     0xF8    /* enable & LED as outputs */
+
 struct exar8250;
 
 struct exar8250_platform {
@@ -236,18 +274,107 @@ static const struct exar8250_platform exar8250_default_platform = {
        .register_gpio = xr17v35x_register_gpio,
 };
 
+static int iot2040_rs485_config(struct uart_port *port,
+                               struct serial_rs485 *rs485)
+{
+       bool is_rs485 = !!(rs485->flags & SER_RS485_ENABLED);
+       u8 __iomem *p = port->membase;
+       u8 mask = IOT2040_UART1_MASK;
+       u8 mode, value;
+
+       if (is_rs485) {
+               if (rs485->flags & SER_RS485_RX_DURING_TX)
+                       mode = IOT2040_UART_MODE_RS422;
+               else
+                       mode = IOT2040_UART_MODE_RS485;
+
+               if (rs485->flags & SER_RS485_TERMINATE_BUS)
+                       mode |= IOT2040_UART_TERMINATE_BUS;
+       } else {
+               mode = IOT2040_UART_MODE_RS232;
+       }
+
+       if (port->line == 3) {
+               mask <<= IOT2040_UART2_SHIFT;
+               mode <<= IOT2040_UART2_SHIFT;
+       }
+
+       value = readb(p + UART_EXAR_MPIOLVL_7_0);
+       value &= ~mask;
+       value |= mode;
+       writeb(value, p + UART_EXAR_MPIOLVL_7_0);
+
+       value = readb(p + UART_EXAR_FCTR);
+       if (is_rs485)
+               value |= UART_FCTR_EXAR_485;
+       else
+               value &= ~UART_FCTR_EXAR_485;
+       writeb(value, p + UART_EXAR_FCTR);
+
+       if (is_rs485)
+               writeb(UART_EXAR_RS485_DLY(4), p + UART_MSR);
+
+       port->rs485 = *rs485;
+
+       return 0;
+}
+
+static const struct property_entry iot2040_gpio_properties[] = {
+       PROPERTY_ENTRY_U32("linux,first-pin", 10),
+       PROPERTY_ENTRY_U32("ngpios", 1),
+       { }
+};
+
+static int iot2040_register_gpio(struct pci_dev *pcidev,
+                             struct uart_8250_port *port)
+{
+       u8 __iomem *p = port->port.membase;
+
+       writeb(IOT2040_UARTS_DEFAULT_MODE, p + UART_EXAR_MPIOLVL_7_0);
+       writeb(IOT2040_UARTS_GPIO_LO_MODE, p + UART_EXAR_MPIOSEL_7_0);
+       writeb(IOT2040_UARTS_ENABLE, p + UART_EXAR_MPIOLVL_15_8);
+       writeb(IOT2040_UARTS_GPIO_HI_MODE, p + UART_EXAR_MPIOSEL_15_8);
+
+       port->port.private_data =
+               __xr17v35x_register_gpio(pcidev, iot2040_gpio_properties);
+
+       return 0;
+}
+
+static const struct exar8250_platform iot2040_platform = {
+       .rs485_config = iot2040_rs485_config,
+       .register_gpio = iot2040_register_gpio,
+};
+
+static const struct dmi_system_id exar_platforms[] = {
+       {
+               .matches = {
+                       DMI_EXACT_MATCH(DMI_BOARD_NAME, "SIMATIC IOT2000"),
+                       DMI_EXACT_MATCH(DMI_BOARD_ASSET_TAG,
+                                       "6ES7647-0AA00-1YA2"),
+               },
+               .driver_data = (void *)&iot2040_platform,
+       },
+       {}
+};
+
 static int
 pci_xr17v35x_setup(struct exar8250 *priv, struct pci_dev *pcidev,
                   struct uart_8250_port *port, int idx)
 {
        const struct exar8250_board *board = priv->board;
        const struct exar8250_platform *platform;
+       const struct dmi_system_id *dmi_match;
        unsigned int offset = idx * 0x400;
        unsigned int baud = 7812500;
        u8 __iomem *p;
        int ret;
 
-       platform = &exar8250_default_platform;
+       dmi_match = dmi_first_match(exar_platforms);
+       if (dmi_match)
+               platform = dmi_match->driver_data;
+       else
+               platform = &exar8250_default_platform;
 
        port->port.uartclk = baud * 16;
        port->port.rs485_config = platform->rs485_config;