On Thu, May 23, 2013 at 04:16:13PM +0800, Huang Shijie wrote:
> The WEIM(Wireless External Interface Module) works like a bus.
> You can attach many different devices on it, such as NOR, onenand.
>
> In the case of i.MX6q-sabreauto, the NOR is connected to WEIM.
>
> This patch also adds the devicetree binding document.
> The driver only works when the devicetree is enabled.
>
> Signed-off-by: Huang Shijie <[email protected]>
> ---
> Documentation/devicetree/bindings/bus/imx-weim.txt | 50 +++++++
> drivers/bus/Kconfig | 9 ++
> drivers/bus/Makefile | 1 +
> drivers/bus/imx-weim.c | 146
> ++++++++++++++++++++
> 4 files changed, 206 insertions(+), 0 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/bus/imx-weim.txt
> create mode 100644 drivers/bus/imx-weim.c
>
> diff --git a/Documentation/devicetree/bindings/bus/imx-weim.txt
> b/Documentation/devicetree/bindings/bus/imx-weim.txt
> new file mode 100644
> index 0000000..3db588e
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/bus/imx-weim.txt
> @@ -0,0 +1,50 @@
> +Device tree bindings for i.MX Wireless External Interface Module (WEIM)
> +
> +The term "wireless" does not imply that the WEIM is literally an interface
> +without wires. It simply means that this module was originally designed for
> +wireless and mobile applications that use low-power technology.
> +
> +The actual devices are instantiated from the child nodes of a WEIM node.
> +
> +
> + - compatible: Should be set to "fsl,imx6q-weim"
> + - reg: A resource specifier for the register space
> + (see the example below)
> + - interrupts: the interrupt number, see the example below.
> + - clocks: the clock, see the example below.
> + - #address-cells: Must be set to 2 to allow memory address translation
> + - #size-cells: Must be set to 1 to allow CS address passing
> + - ranges: Must be set up to reflect the memory layout with four
> + integer values for each chip-select line in use:
> +
> + <cs-number> 0 <physical address of mapping> <size>
> +
> +Timing property for child nodes. It is mandatory, not optional.
> +
> + - fsl,weim-cs-timing: The timing array, contains 6 timing values for
> the
> + child node. We can get the CS index from the child
> + node's "reg" property.
This should be more detailed, something like:
This contains the values for the registers EIM_CSnGCR1, EIM_CSnGCR2,
EIM_CSnRCR1, EIM_CSnRCR2, EIM_CSnWCR1, EIM_CSnWCR2 in this order.
> +static int weim_parse_dt(struct platform_device *pdev)
> +{
> + struct device_node *child;
> + int ret;
> +
> + for_each_child_of_node(pdev->dev.of_node, child) {
> + if (!child->name)
> + continue;
> +
> + ret = weim_timing_setup(pdev, child);
> + if (ret)
> + goto parse_fail;
> +
> + if (!of_platform_device_create(child, NULL, &pdev->dev)) {
> + ret = -EINVAL;
> + goto parse_fail;
> + }
I would print some warning here for the failures in this loop, but I
don't think it's necessary to bail out. No need to make all WEIM devices
fail if one has an erroneous device node.
> +
> + /* get the resource */
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + weim->base = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(weim->base)) {
> + ret = PTR_ERR(weim->base);
> + goto weim_err;
> + }
> +
> + /* get the clock */
> + weim->clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(weim->clk))
> + goto weim_err;
> +
> + clk_prepare_enable(weim->clk);
> +
> + /* parse the device node */
> + ret = weim_parse_dt(pdev);
> + if (ret) {
> + clk_disable_unprepare(weim->clk);
> + goto weim_err;
> + }
> +
> + dev_info(&pdev->dev, "WEIM driver registered.\n");
> + return 0;
> +
> +weim_err:
> + return ret;
> +}
> +
> +static int weim_remove(struct platform_device *pdev)
> +{
> + struct imx_weim *weim = platform_get_drvdata(pdev);
> +
> + clk_disable_unprepare(weim->clk);
Once again: Is this clock needed for the child devices? If yes, you
can't disable it here and leave the child devices registered.
Sascha
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