Some platforms e.g. TI Davinci require 32-bit accesses to the UARTs.
The of_serial driver currently registers all UARTs as UPIO_MEM. Add a
new attribute "io-width" to allow the port to be registered with
different IO width requirements.
Acked-by: Alan Cox <alan@xxxxxxxxxxxxxxx>
Acked-by: Grant Likely <grant.likely@xxxxxxxxxxxx>
Signed-off-by: Jamie Iles <jamie@xxxxxxxxxxxxx>
---
.../devicetree/bindings/tty/serial/of-serial.txt | 3 +++
drivers/tty/serial/of_serial.c | 17 +++++++++++++++++
2 files changed, 20 insertions(+), 0 deletions(-)
diff --git a/Documentation/devicetree/bindings/tty/serial/of-serial.txt b/Documentation/devicetree/bindings/tty/serial/of-serial.txt
index 35e53ae..93260d0 100644
--- a/Documentation/devicetree/bindings/tty/serial/of-serial.txt
+++ b/Documentation/devicetree/bindings/tty/serial/of-serial.txt
@@ -21,6 +21,9 @@ Optional properties:
- reg-shift : quantity to shift the register offsets by.
- used-by-rtas : set to indicate that the port is in use by the OpenFirmware
RTAS and should not be registered.
+- io-width : the size (in bytes) of the IO accesses that should be performed
+ on the device. There are some systems that require 32-bit accesses to the
+ UART (e.g. TI davinci).
Example:
diff --git a/drivers/tty/serial/of_serial.c b/drivers/tty/serial/of_serial.c
index c911b24..dfcad6f 100644
--- a/drivers/tty/serial/of_serial.c
+++ b/drivers/tty/serial/of_serial.c
@@ -65,6 +65,23 @@ static int __devinit of_platform_serial_setup(struct platform_device *ofdev,
port->irq = irq_of_parse_and_map(np, 0);
port->iotype = UPIO_MEM;
+ prop = of_get_property(np, "io-width", &prop_size);
+ if (prop && (prop_size == sizeof(u32))) {
+ switch (be32_to_cpup(prop)) {
+ case 1:
+ port->iotype = UPIO_MEM;
+ break;
+ case 4:
+ port->iotype = UPIO_MEM32;
+ break;
+ default:
+ dev_warn(&ofdev->dev,
+ "unsupported io width (%d bytes)\n",
+ be32_to_cpup(prop));
+ return -EINVAL;
+ }
+ }
+
port->type = type;
port->uartclk = be32_to_cpup(clk);
port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
--
1.7.4.1
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