[U-Boot] [PATCH v3 4/6] mvebu: usb: xhci: Add VBUS regulator supply to the host driver

[Konstantin Porotchkin <kostap@marvell.com>]

On 02/08/2017 06:42 PM, Marek Vasut wrote:
> On 02/08/2017 05:28 PM, Konstantin Porotchkin wrote:
>> Hi, Marek,
>>
>> On 02/08/2017 06:04 PM, Marek Vasut wrote:
>>> On 02/08/2017 04:45 PM, Konstantin Porotchkin wrote:
>>>> Hi, Marek,
>>>>
>>>> On 02/08/2017 05:35 PM, Marek Vasut wrote:
>>>>> On 02/08/2017 04:34 PM, kostap at marvell.com wrote:
>>>>>> From: Konstantin Porotchkin <kostap@marvell.com>
>>>>>>
>>>>>> The USB device should linked to VBUS regulator through "vbus-supply"
>>>>>> DTS property.
>>>>>> This patch adds handling for "vbus-supply" property inside the USB
>>>>>> device entry for turning on the VBUS regulator upon the host adapter
>>>>> probe.
>>>>>>
>>>>>> Change-Id: Ibcf72d82298be42353ca03fee064ae8077a7b9de
>>>>>> Signed-off-by: Konstantin Porotchkin <kostap@marvell.com>
>>>>>> Cc: Stefan Roese <sr@denx.de>
>>>>>> Cc: Marek Vasut <marex@denx.de>
>>>>>> Cc: Nadav Haklai <nadavh@marvell.com>
>>>>>> Cc: Neta Zur Hershkovits <neta@marvell.com>
>>>>>> Cc: Igal Liberman <igall@marvell.com>
>>>>>> Cc: Haim Boot <hayim@marvell.com>
>>>>>> ---
>>>>>> Changes for v3:
>>>>>> - Moved VBUS control from private GPIO to a fixed regulator
>>>>>> - Rebase on top of master branch
>>>>>>
>>>>>>
>>>>>>  doc/device-tree-bindings/usb/marvell.xhci-usb.txt | 28
>>>>> ++++++++++++++++++++
>>>>>>  drivers/usb/host/xhci-mvebu.c                     | 31
>>>>> +++++++++++++++++++++++
>>>>>>  2 files changed, 59 insertions(+)
>>>>>>  create mode 100644 doc/device-tree-bindings/usb/marvell.xhci-usb.txt
>>>>>>
>>>>>> diff --git a/doc/device-tree-bindings/usb/marvell.xhci-usb.txt
>>>>> b/doc/device-tree-bindings/usb/marvell.xhci-usb.txt
>>>>>> new file mode 100644
>>>>>> index 0000000..672a829
>>>>>> --- /dev/null
>>>>>> +++ b/doc/device-tree-bindings/usb/marvell.xhci-usb.txt
>>>>>> @@ -0,0 +1,28 @@
>>>>>> +Marvell SOC USB controllers
>>>>>> +
>>>>>> +This controller is integrated in Armada 3700/8K.
>>>>>> +It uses the same properties as a generic XHCI host controller
>>>>>> +
>>>>>> +Required properties :
>>>>>> + - compatible: should be one or more of:
>>>>>> +   - "marvell,armada3700-xhci", "generic-xhci" for Armada 37xx SoCs
>>>>>> +   - "marvell,armada-8k-xhci", "generic-xhci" for Armada A8K SoCs
>>>>>> + - reg: should contain address and length of the standard XHCI
>>>>>> +   register set for the device.
>>>>>> + - interrupts: one XHCI interrupt should be described here.
>>>>>> +
>>>>>> +Optional properties:
>>>>>> + - clocks: reference to a clock
>>>>>
>>>>> What clock ? Why are clock optional ?
>>>>> This probably needs clock-names too.
>>>> This is the way it defined in Linux Kernel.
>>>
>>> Then it probably could use fixing there too. Like seriously, what clock
>>> are those ? And why are they optional ? If neither you or me understand
>>> that from the documentation, then the documentation is crap and needs
>>> fixing. It being the same way in Linux is not an argument for sticking
>>> to it.
>> From my point of view this clock entry is optional too.
>> I am not handling it in any way and the core XHCI driver doesn't uses it.
>
> DT is describing the hardware, not the software that is using it. These
> two things are separate. If the clock are mandatory for the hardware to
> work, they must be mandatory in the DT.
I see what you saying. I will move the "clocks" entry to the "mandatory" 
section. Please keep in mind that it will not be currently enforced by 
the SW. For USB 3.0 case the clock parameters are actually defined by 
SERDES configuration, which has a separate DTS entry.
>
>> Should I simply remove this property from the text file?
>
> See above.
>
>>>> I took the Documentation/devicetree/bindings/usb/usb-xhci.txt file as a
>>>> base for my add-on
>>>>>
>>>>>> + - vbus-supply : If present, specifies the fixed regulator to be
>>>>> turned on
>>>>>> +   for providing power to the USB VBUS rail.
>>>>>> +
>>>>>> +Example:
>>>>>> +    cpm_usb3_0: usb3 at 500000 {
>>>>>> +        compatible = "marvell,armada-8k-xhci",
>>>>>> +                 "generic-xhci";
>>>>>> +        reg = <0x500000 0x4000>;
>>>>>> +        interrupts = <GIC_SPI 62 IRQ_TYPE_LEVEL_HIGH>;
>>>>>> +        clocks = <&cpm_syscon0 1 22>;
>>>>>> +        vbus-supply = <&reg_usb3h0_vbus>;
>>>>>> +        status = "disabled";
>>>>>> +    };
>>>>>> diff --git a/drivers/usb/host/xhci-mvebu.c
>>>>> b/drivers/usb/host/xhci-mvebu.c
>>>>>> index 46eb937..149f6a4 100644
>>>>>> --- a/drivers/usb/host/xhci-mvebu.c
>>>>>> +++ b/drivers/usb/host/xhci-mvebu.c
>>>>>> @@ -45,7 +45,38 @@ static int xhci_usb_probe(struct udevice *dev)
>>>>>>      struct mvebu_xhci *ctx = dev_get_priv(dev);
>>>>>>      struct xhci_hcor *hcor;
>>>>>>      int len;
>>>>>> +#ifdef CONFIG_DM_REGULATOR_FIXED
>>>>>
>>>>> Just make the driver depend on REGULATOR_FIXED
>>>> I think the driver can work without regulator if the VBUS rail wired to
>>>> the 5V power line.
>>>> We only need regulator support if this is GPIO controlled
>>>
>>> In that case, the regulator won't be found and the driver will ignore
>>> it. Btw I think that violates the USB spec ;-)
>>>
>> Currently the armada-8040-DB/armada-7040-DB boards use i2c connected
>> VBUS enable control. If I made this driver depend on REGULATOR_FIXED,
>> it will not work for these boards. They do not have regulator support
>> enabled so far.
>> I do not want to break another systems by adding support for this board.
>
> Oh, right. Then I believe using the regulator framework will help. The
> driver can depend on the regulator framework, which will abstract away
> the used regulator.
Got it. I will change the code for using the regulator framework in USB 
driver.
>
>>>>>> +    const void *fdt = gd->fdt_blob;
>>>>>> +    int node = dev->of_offset;
>>>>>> +    const fdt32_t *regulator;
>>>>>> +    int size;
>>>>>>
>>>>>> +    /*
>>>>>> +     * The VBUS supply regulator is not probed automatically
>>>>>> +     * Trigger the regulator probe upon USB port bring up
>>>>>> +     */
>>>>>> +    regulator = fdt_getprop(fdt, node, "vbus-supply", &size);
>>>
>>> I think this should use regulator_*() calls from
>>> include/power/regulator.h
>> I can call regulator_set_enable() at the end, but I have to locate it
>> first and get the udev for it.
>> However it will be enabled already at the time I will call this function.
>
> regulator_get_by_platname("vbus-supply", &reg); doesn't work here ?
Thank you for the tip! i will definitely try this. Unfortunately I am 
not yet fluent in all the available DM APIs.
>
>>>>>> +    if (regulator) {
>>>>>> +        uint32_t phandle;
>>>>>> +        struct udevice *config;
>>>>>> +        int reg_node, ret;
>>>>>> +
>>>>>> +        phandle = fdt32_to_cpu(*regulator);
>>>>>> +        reg_node = fdt_node_offset_by_phandle(fdt, phandle);
>>>>>> +        if (reg_node < 0) {
>>>>>> +            dev_err(dev, "vbus-supply has invalid phandle\n");
>>>>>> +            return -EINVAL;
>>>>>> +        }
>>>>>> +        ret = uclass_get_device_by_of_offset(UCLASS_REGULATOR,
>>>>>> +                             reg_node, &config);
>>>>>> +        if (ret) {
>>>>>> +            dev_err(dev, "failed to get VBUS regulator device\n");
>>>>>> +            return ret;
>>>>>
>>>>> Where is the regulator enabled ?
>>>> The regulator is fixed and it is "always-on", so assumed it is enough to
>>>> probe it.
>>>> I have found that once it probed, the USB device becomes powered.
>>>
>>> And once someone attaches a different regulator than fixed, this will
>>> break :)
>> What other type of regulators can be used for powering on the USB port?
>> I believe they are always 5V fixed, are they?
>
> Anything which can turn 5V on/off , be it some i2c chip, spi chip, GPIO ...
>