Re: [PATCH 2/2] tty: of_serial: support for 32 bit accesses

[Grant Likely <grant.likely@secretlab.ca>]

On Wed, Jun 15, 2011 at 6:49 AM, Jamie Iles <jamie@jamieiles.com> wrote:
> 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.
>
> Cc: Alan Cox <alan@linux.intel.com>
> Cc: Grant Likely <grant.likely@secretlab.ca>
> Signed-off-by: Jamie Iles <jamie@jamieiles.com>
> ---
>  .../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 b0c52c2..1771cda 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 firmware 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 4675243..50810a0 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;

Nit: since this is failing out, it should be dev_err instead of
dev_warn, but otherwise:

Acked-by: Grant Likely <grant.likely@secretlab.ca>

g.

> +               }
> +       }
> +
>        port->type = type;
>        port->uartclk = be32_to_cpup(clk);
>        port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
> --
> 1.7.4.1
>
>



-- 
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.
--
To unsubscribe from this list: send the line "unsubscribe linux-serial" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html