Hi Manu,
On mer., févr. 28 2018, Manu Gautam <mgautam@xxxxxxxxxxxxxx> wrote:
> Hi,
>
>
> On 2/14/2018 9:46 PM, Gregory CLEMENT wrote:
>> On Armada 7K/8K we need to explicitly enable the register clock. This
>> clock is optional because not all the SoCs using this IP need it but at
>> least for Armada 7K/8K it is actually mandatory.
>>
>> The change was done at xhci-plat level and not at a xhci-mvebu.c because,
>> it is expected that other SoC would have this kind of constraint.
>>
>> The binding documentation is updating accordingly.
>>
>> Signed-off-by: Gregory CLEMENT <gregory.clement@xxxxxxxxxxx>
>> ---
>> Documentation/devicetree/bindings/usb/usb-xhci.txt | 5 +++-
>> drivers/usb/host/xhci-plat.c | 33 ++++++++++++++++++----
>> drivers/usb/host/xhci.h | 3 +-
>> 3 files changed, 33 insertions(+), 8 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/usb/usb-xhci.txt b/Documentation/devicetree/bindings/usb/usb-xhci.txt
>> index e2ea59bbca93..e4b14511f4f8 100644
>> --- a/Documentation/devicetree/bindings/usb/usb-xhci.txt
>> +++ b/Documentation/devicetree/bindings/usb/usb-xhci.txt
>> @@ -27,7 +27,10 @@ Required properties:
>> - interrupts: one XHCI interrupt should be described here.
>>
>> Optional properties:
>> - - clocks: reference to a clock
>> + - clocks: reference to the clocks
>> + - clock-names: mandatory if there is a second clock, in this case
>> + the name must be "core" for the first clock and "reg" for the
>> + second one
>> - usb2-lpm-disable: indicate if we don't want to enable USB2 HW LPM
>> - usb3-lpm-capable: determines if platform is USB3 LPM capable
>> - quirk-broken-port-ped: set if the controller has broken port disable mechanism
>> diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
>> index 79afaac57ef6..fd0c399013a2 100644
>> --- a/drivers/usb/host/xhci-plat.c
>> +++ b/drivers/usb/host/xhci-plat.c
>> @@ -157,6 +157,7 @@ static int xhci_plat_probe(struct platform_device *pdev)
>> struct resource *res;
>> struct usb_hcd *hcd;
>> struct clk *clk;
>> + struct clk *reg_clk;
>> int ret;
>> int irq;
>>
>> @@ -226,17 +227,27 @@ static int xhci_plat_probe(struct platform_device *pdev)
>> hcd->rsrc_len = resource_size(res);
>>
>> /*
>> - * Not all platforms have a clk so it is not an error if the
>> - * clock does not exists.
>> + * Not all platforms have clks so it is not an error if the
>> + * clock do not exist.
>> */
>> + reg_clk = devm_clk_get(&pdev->dev, "reg");
>> + if (!IS_ERR(reg_clk)) {
>> + ret = clk_prepare_enable(reg_clk);
>> + if (ret)
>> + goto put_hcd;
>> + } else if (PTR_ERR(reg_clk) == -EPROBE_DEFER) {
>> + ret = -EPROBE_DEFER;
>> + goto put_hcd;
>> + }
>> +
>
> How about using clk_bulk_ APIs?
I didn't know this API, but after having a look on it, it didn't match
what I need. Indeed the second clock is "optional" to handle the
backward compatibility. With the clk_bulk_ APIS all the clocks are
mandatory.
Thanks,
Gregory
>
>> clk = devm_clk_get(&pdev->dev, NULL);
>> if (!IS_ERR(clk)) {
>> ret = clk_prepare_enable(clk);
>>
>
> --
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
>
>
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--
Gregory Clement, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
http://bootlin.com
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