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    SubjectRe: [PATCH 1/3] serial/imx: add device tree support
    Hi Grant,

    I just gave a try to use aliases node for identify the device index.
    Please take a look and let me know if it's what you expect.

    On Sun, Jun 19, 2011 at 03:30:02PM +0800, Shawn Guo wrote:
    [...]
    > > >
    > > > +#ifdef CONFIG_OF
    > > > +static int serial_imx_probe_dt(struct imx_port *sport,
    > > > + struct platform_device *pdev)
    > > > +{
    > > > + struct device_node *node = pdev->dev.of_node;
    > > > + const __be32 *line;
    > > > +
    > > > + if (!node)
    > > > + return -ENODEV;
    > > > +
    > > > + line = of_get_property(node, "id", NULL);
    > > > + if (!line)
    > > > + return -ENODEV;
    > > > +
    > > > + sport->port.line = be32_to_cpup(line) - 1;
    > >
    > > Hmmm, I really would like to be rid of this. Instead, if uarts must
    > > be enumerated, the driver should look for a /aliases/uart* property
    > > that matches the of_node. Doing it that way is already established in
    > > the OpenFirmware documentation, and it ensures there are no overlaps
    > > in the global namespace.
    > >
    >
    > I just gave one more try to avoid using 'aliases', and you gave a
    > 'no' again. Now, I know how hard you are on this. Okay, I start
    > thinking about your suggestion seriously :)
    >
    > > We do need some infrastructure to make that easier though. Would you
    > > have time to help put that together?
    > >
    > Ok, I will give it a try.
    >

    diff --git a/arch/arm/boot/dts/imx51-babbage.dts b/arch/arm/boot/dts/imx51-babbage.dts
    index da0381a..f4a5c3c 100644
    --- a/arch/arm/boot/dts/imx51-babbage.dts
    +++ b/arch/arm/boot/dts/imx51-babbage.dts
    @@ -18,6 +18,12 @@
    compatible = "fsl,imx51-babbage", "fsl,imx51";
    interrupt-parent = <&tzic>;

    + aliases {
    + serial0 = &uart0;
    + serial1 = &uart1;
    + serial2 = &uart2;
    + };
    +
    chosen {
    bootargs = "console=ttymxc0,115200 root=/dev/mmcblk0p3 rootwait";
    };
    @@ -47,29 +53,29 @@
    reg = <0x70000000 0x40000>;
    ranges;

    - uart@7000c000 {
    + uart2: uart@7000c000 {
    compatible = "fsl,imx51-uart", "fsl,imx21-uart";
    reg = <0x7000c000 0x4000>;
    interrupts = <33>;
    id = <3>;
    - fsl,has-rts-cts;
    + fsl,uart-has-rtscts;
    };
    };

    - uart@73fbc000 {
    + uart0: uart@73fbc000 {
    compatible = "fsl,imx51-uart", "fsl,imx21-uart";
    reg = <0x73fbc000 0x4000>;
    interrupts = <31>;
    id = <1>;
    - fsl,has-rts-cts;
    + fsl,uart-has-rtscts;
    };

    - uart@73fc0000 {
    + uart1: uart@73fc0000 {
    compatible = "fsl,imx51-uart", "fsl,imx21-uart";
    reg = <0x73fc0000 0x4000>;
    interrupts = <32>;
    id = <2>;
    - fsl,has-rts-cts;
    + fsl,uart-has-rtscts;
    };
    };

    diff --git a/drivers/of/base.c b/drivers/of/base.c
    index 632ebae..13df5d2 100644
    --- a/drivers/of/base.c
    +++ b/drivers/of/base.c
    @@ -737,6 +737,37 @@ err0:
    EXPORT_SYMBOL(of_parse_phandles_with_args);

    /**
    + * of_get_device_index - Get device index by looking up "aliases" node
    + * @np: Pointer to device node that asks for device index
    + * @name: The device alias without index number
    + *
    + * Returns the device index if find it, else returns -ENODEV.
    + */
    +int of_get_device_index(struct device_node *np, const char *alias)
    +{
    + struct device_node *aliases = of_find_node_by_name(NULL, "aliases");
    + struct property *prop;
    + char name[32];
    + int index = 0;
    +
    + if (!aliases)
    + return -ENODEV;
    +
    + while (1) {
    + snprintf(name, sizeof(name), "%s%d", alias, index);
    + prop = of_find_property(aliases, name, NULL);
    + if (!prop)
    + return -ENODEV;
    + if (np == of_find_node_by_path(prop->value))
    + break;
    + index++;
    + }
    +
    + return index;
    +}
    +EXPORT_SYMBOL(of_get_device_index);
    +
    +/**
    * prom_add_property - Add a property to a node
    */
    int prom_add_property(struct device_node *np, struct property *prop)
    diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
    index da436e0..852668f 100644
    --- a/drivers/tty/serial/imx.c
    +++ b/drivers/tty/serial/imx.c
    @@ -1271,18 +1271,18 @@ static int serial_imx_probe_dt(struct imx_port *sport,
    struct device_node *node = pdev->dev.of_node;
    const struct of_device_id *of_id =
    of_match_device(imx_uart_dt_ids, &pdev->dev);
    - const __be32 *line;
    + int line;

    if (!node)
    return -ENODEV;

    - line = of_get_property(node, "id", NULL);
    - if (!line)
    + line = of_get_device_index(node, "serial");
    + if (IS_ERR_VALUE(line))
    return -ENODEV;

    - sport->port.line = be32_to_cpup(line) - 1;
    + sport->port.line = line;

    - if (of_get_property(node, "fsl,has-rts-cts", NULL))
    + if (of_get_property(node, "fsl,uart-has-rtscts", NULL))
    sport->have_rtscts = 1;

    if (of_get_property(node, "fsl,irda-mode", NULL))
    diff --git a/include/linux/of.h b/include/linux/of.h
    index bfc0ed1..3153752 100644
    --- a/include/linux/of.h
    +++ b/include/linux/of.h
    @@ -213,6 +213,8 @@ extern int of_parse_phandles_with_args(struct device_node *np,
    const char *list_name, const char *cells_name, int index,
    struct device_node **out_node, const void **out_args);

    +extern int of_get_device_index(struct device_node *np, const char *alias);
    +
    extern int of_machine_is_compatible(const char *compat);

    extern int prom_add_property(struct device_node* np, struct property* prop);
    --
    Regards,
    Shawn



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