serial: vt8500: Add devicetree support for vt8500-serial

Increase vt8500_max_ports to 6 as the WM8505 as 6 available uarts.
Use devicetree port id as primary addressing for ports but allow
auto-allocation if id not specified.

Signed-off-by: Tony Prisk <linux@prisktech.co.nz>
Acked-by: Alan Cox <alan@linux.intel.com>

1 files changed, 53 insertions, 5 deletions

diff --git a/drivers/tty/serial/vt8500_serial.c b/drivers/tty/serial/vt8500_serial.c
index 2be006fb3da0..205d4cf4a063 100644
--- a/drivers/tty/serial/vt8500_serial.c
+++ b/drivers/tty/serial/vt8500_serial.c
@@ -34,6 +34,7 @@
 #include <linux/slab.h>
 #include <linux/clk.h>
 #include <linux/platform_device.h>
+#include <linux/of.h>
 
 /*
  * UART Register offsets
@@ -76,6 +77,8 @@
 #define RX_FIFO_INTS    (RXFAF | RXFF | RXOVER | PER | FER | RXTOUT)
 #define TX_FIFO_INTS    (TXFAE | TXFE | TXUDR)
 
+#define VT8500_MAX_PORTS        6
+
 struct vt8500_port {
         struct uart_port        uart;
         char                    name[16];
@@ -83,6 +86,13 @@ struct vt8500_port {
         unsigned int            ier;
 };
 
+/*
+ * we use this variable to keep track of which ports
+ * have been allocated as we can't use pdev->id in
+ * devicetree
+ */
+static unsigned long vt8500_ports_in_use;
+
 static inline void vt8500_write(struct uart_port *port, unsigned int val,
                              unsigned int off)
 {
@@ -431,7 +441,7 @@ static int vt8500_verify_port(struct uart_port *port,
         return 0;
 }
 
-static struct vt8500_port *vt8500_uart_ports[4];
+static struct vt8500_port *vt8500_uart_ports[VT8500_MAX_PORTS];
 static struct uart_driver vt8500_uart_driver;
 
 #ifdef CONFIG_SERIAL_VT8500_CONSOLE
@@ -548,7 +558,9 @@ static int __devinit vt8500_serial_probe(struct platform_device *pdev)
 {
         struct vt8500_port *vt8500_port;
         struct resource *mmres, *irqres;
+        struct device_node *np = pdev->dev.of_node;
         int ret;
+        int port;
 
         mmres = platform_get_resource(pdev, IORESOURCE_MEM, 0);
         irqres = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
@@ -559,16 +571,46 @@ static int __devinit vt8500_serial_probe(struct platform_device *pdev)
         if (!vt8500_port)
                 return -ENOMEM;
 
+        if (np)
+                port = of_alias_get_id(np, "serial");
+                if (port > VT8500_MAX_PORTS)
+                        port = -1;
+        else
+                port = -1;
+
+        if (port < 0) {
+                /* calculate the port id */
+                port = find_first_zero_bit(&vt8500_ports_in_use,
+                                        sizeof(vt8500_ports_in_use));
+        }
+
+        if (port > VT8500_MAX_PORTS)
+                return -ENODEV;
+
+        /* reserve the port id */
+        if (test_and_set_bit(port, &vt8500_ports_in_use)) {
+                /* port already in use - shouldn't really happen */
+                return -EBUSY;
+        }
+
         vt8500_port->uart.type = PORT_VT8500;
         vt8500_port->uart.iotype = UPIO_MEM;
         vt8500_port->uart.mapbase = mmres->start;
         vt8500_port->uart.irq = irqres->start;
         vt8500_port->uart.fifosize = 16;
         vt8500_port->uart.ops = &vt8500_uart_pops;
-        vt8500_port->uart.line = pdev->id;
+        vt8500_port->uart.line = port;
         vt8500_port->uart.dev = &pdev->dev;
         vt8500_port->uart.flags = UPF_IOREMAP | UPF_BOOT_AUTOCONF;
-        vt8500_port->uart.uartclk = 24000000;
+
+        vt8500_port->clk = of_clk_get(pdev->dev.of_node, 0);
+        if (vt8500_port->clk) {
+                vt8500_port->uart.uartclk = clk_get_rate(vt8500_port->clk);
+        } else {
+                /* use the default of 24Mhz if not specified and warn */
+                pr_warn("%s: serial clock source not specified\n", __func__);
+                vt8500_port->uart.uartclk = 24000000;
+        }
 
         snprintf(vt8500_port->name, sizeof(vt8500_port->name),
                  "VT8500 UART%d", pdev->id);
@@ -579,7 +621,7 @@ static int __devinit vt8500_serial_probe(struct platform_device *pdev)
                 goto err;
         }
 
-        vt8500_uart_ports[pdev->id] = vt8500_port;
+        vt8500_uart_ports[port] = vt8500_port;
 
         uart_add_one_port(&vt8500_uart_driver, &vt8500_port->uart);
 
@@ -603,12 +645,18 @@ static int __devexit vt8500_serial_remove(struct platform_device *pdev)
         return 0;
 }
 
+static const struct of_device_id wmt_dt_ids[] = {
+        { .compatible = "via,vt8500-uart", },
+        {}
+};
+
 static struct platform_driver vt8500_platform_driver = {
         .probe  = vt8500_serial_probe,
         .remove = __devexit_p(vt8500_serial_remove),
         .driver = {
                 .name = "vt8500_serial",
                 .owner = THIS_MODULE,
+                .of_match_table = of_match_ptr(wmt_dt_ids),
         },
 };
 
@@ -642,4 +690,4 @@ module_exit(vt8500_serial_exit);
 
 MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>");
 MODULE_DESCRIPTION("Driver for vt8500 serial device");
-MODULE_LICENSE("GPL");
+MODULE_LICENSE("GPL v2");