Re: [PATCH v3] extcon: add Maxim MAX3355 driver

[Sergei Shtylyov]

Hello.

On 12/17/2015 3:53 AM, Krzysztof Kozlowski wrote:

> > Maxim Integrated MAX3355E chip integrates a charge pump and comparators to
> > enable a system with an integrated USB OTG dual-role transceiver to
> > function as an USB OTG dual-role device. In addition to sensing/controlling
> > Vbus, the chip also passes thru the ID signal from the USB OTG connector.
> > On some Renesas boards, this signal is just fed into the SoC thru a GPIO
> > pin -- there's no real OTG controller, only host and gadget USB controllers
> > sharing the same USB bus; however, we'd like to allow host or gadget
> > drivers to be loaded depending on the cable type, hence the need for the
> > MAX3355 extcon driver. The Vbus status signals are also wired to GPIOs
> > (however, we aren't currently interested in them), the OFFVBUS# signal is
> > controlled by the host controllers, there's also the SHDN# signal wired to
> > a GPIO, it should be driven high for the normal operation.
> >
> > Signed-off-by: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
> >
> > ---
> > Changes in version 3:
> > - reformatted the change log.
> >
> > Changes in version 2:
> > - added the USB gadget cable support;
> > - added the remove() driver method which drives SHDN# GPIO low to save power;
> > - dropped vendor prefix from the ID GPIO property name;
> > - changed the GPIO property name suffix to "-gpios";
> > - switched to usign extcon_set_cable_state_() API;
> > - switched to using the gpiod/sleeping 'gpiolib' APIs;
> > - addded error messages to max3355_probe();
> > - added IRQF_NO_SUSPEND flasg to the devm_request_threaded_irq() call;
> > - renamed 'ret' variable to 'err' in max3355_probe();
> > - expanded the Kconfig entry help text;
> > - added vendor name to the patch summary, the bindings document, the Kconfig
> >    entry, the driver heading comment, the module description, and the change log;
> > - fixed up and reformatted the change log.
> >
> >   Documentation/devicetree/bindings/extcon/extcon-max3355.txt |   21 +
> >   drivers/extcon/Kconfig                                      |    8
> >   drivers/extcon/Makefile                                     |    1
> >   drivers/extcon/extcon-max3355.c                             |  153 ++++++++++++
> >   4 files changed, 183 insertions(+)
> >
> > Index: renesas/Documentation/devicetree/bindings/extcon/extcon-max3355.txt
> > ===================================================================
> > --- /dev/null
> > +++ renesas/Documentation/devicetree/bindings/extcon/extcon-max3355.txt
> > @@ -0,0 +1,21 @@
> > +Maxim Integrated MAX3355 USB OTG chip
> > +-------------------------------------
> > +
> > +MAX3355 integrates a charge pump and comparators to enable a system with an
> > +integrated USB OTG dual-role transceiver to function as a USB OTG dual-role
> > +device.
> > +
> > +Required properties:
> > +- compatible: should be "maxim,max3355";
> > +- maxim,shdn-gpios: should contain a phandle and GPIO specifier for the GPIO pin
> > +  connected to the MAX3355's SHDN# pin;
>
> Could you add some indentation to the wrapped line for this property?
> For readability.

   If it's not indented enough, I can add more spaces/tabs.

> > +- id-gpios: should contain a phandle and GPIO specifier for the GPIO pin
> > +  connected to the MAX3355's ID_OUT pin.
>
> Ditto.
>
> Why this property lacks the vendor prefix i(n comparison to shdn-gpios
> which has the prefix)?

   Since the extcon-usb-gpio driver uses "id-gpio" prop already. I can add 
back the vendor prefix if you insist.

[...]
> > Index: renesas/drivers/extcon/extcon-max3355.c
> > ===================================================================
> > --- /dev/null
> > +++ renesas/drivers/extcon/extcon-max3355.c
> > @@ -0,0 +1,153 @@
[...]
> > +static int max3355_probe(struct platform_device *pdev)
> > +{
> > +       struct device_node *np = pdev->dev.of_node;
> > +       struct max3355_data *data;
> > +       struct gpio_desc *gpiod;
> > +       int irq, err;
> > +
> > +       data = devm_kzalloc(&pdev->dev, sizeof(struct max3355_data),
> > +                           GFP_KERNEL);
> > +       if (!data)
> > +               return -ENOMEM;
> > +
> > +       data->edev = devm_extcon_dev_allocate(&pdev->dev, max3355_cable);
> > +       if (IS_ERR(data->edev)) {
> > +               dev_err(&pdev->dev, "failed to allocate extcon device\n");
> > +               return PTR_ERR(data->edev);
> > +       }
> > +       data->edev->name = kstrdup(np->name, GFP_KERNEL);
>
> I think it is not needed any more (extcon_dev_register()) will set it.
> Anyway there is no checking for NULL return value and no freeing in
> error/exit paths.

   Oops, will fix.

[...]
> > +static struct platform_driver max3355_driver = {
> > +       .probe          = max3355_probe,
> > +       .remove         = max3355_remove,
> > +       .driver         = {
> > +               .name   = "extcon-max3355",
> > +               .of_match_table = max3355_match_table,
> > +               .owner  = THIS_MODULE,
>
> No need for owner.
> Please pass the source through recent coccicheck and fix the findings.

   Has it been included in the kernel source somewhere already?

> Best regards,
> Krzysztof

MBR, Sergei

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