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SubjectRe: [Patch V3 03/18] phy: tegra: xusb: Add usb-role-switch support
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On 28-01-2020 23:02, Thierry Reding wrote:
> On Mon, Dec 30, 2019 at 04:39:40PM +0530, Nagarjuna Kristam wrote:
>> If usb-role-switch property is present in USB 2 port, register
>> usb-role-switch to receive usb role changes.
>>
>> Signed-off-by: Nagarjuna Kristam<nkristam@nvidia.com>
>> ---
>> V3:
>> - Driver aborts if usb-role-switch is not added in dt forotg/peripheral
>> roles.
>> - Added role name strings instead of enum values in debug prints.
>> - Updated arguments and variable allignments as per Thierry inputs.
>> ---
>> V2:
>> - Removed dev_set_drvdata for port->dev.
>> - Added of_platform_depopulate during error handling and driver removal.
>> ---
>> drivers/phy/tegra/Kconfig | 1 +
>> drivers/phy/tegra/xusb.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++
>> drivers/phy/tegra/xusb.h | 3 +++
>> 3 files changed, 61 insertions(+)
>>
>> diff --git a/drivers/phy/tegra/Kconfig b/drivers/phy/tegra/Kconfig
>> index f9817c3..df07c4d 100644
>> --- a/drivers/phy/tegra/Kconfig
>> +++ b/drivers/phy/tegra/Kconfig
>> @@ -2,6 +2,7 @@
>> config PHY_TEGRA_XUSB
>> tristate "NVIDIA Tegra XUSB pad controller driver"
>> depends on ARCH_TEGRA
>> + select USB_CONN_GPIO
>> help
>> Choose this option if you have an NVIDIA Tegra SoC.
>>
>> diff --git a/drivers/phy/tegra/xusb.c b/drivers/phy/tegra/xusb.c
>> index f98ec39..11ea9b5 100644
>> --- a/drivers/phy/tegra/xusb.c
>> +++ b/drivers/phy/tegra/xusb.c
>> @@ -523,6 +523,7 @@ static int tegra_xusb_port_init(struct tegra_xusb_port *port,
>> port->dev.type = &tegra_xusb_port_type;
>> port->dev.of_node = of_node_get(np);
>> port->dev.parent = padctl->dev;
>> + port->dev.driver = padctl->dev->driver;
> This looks wrong. I don't think driver's are supposed to set this
> because it basically means that the device is being attached to the
> driver, but in this case it doesn't get probed by the driver and in
> fact the ports don't match the pad controller, so they can't really
> be driven by the same driver.
>
> Is there any particular reason why you need this?
>
> Thierry

Yes, port->dev.driver->owner is accessed in USB role switch driver in
API usb_role_switch_get. If driver param is not updated, it causes NULL
pointer exception. Based on your inputs, since this assignment is not
supposed to used, I believe option available is to create a new
device_driver structure and assign the same here.
Please share your thoughts.

- Nagarjuna

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