linux-kernel - Re: [PATCHv2 1/2] extcon: add driver for Intel USB mux

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Message-ID: <5660952A.4010108@cogentembedded.com>
Date:	Thu, 3 Dec 2015 22:16:58 +0300
From:	Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
To:	Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
	Chanwoo Choi <cw00.choi@...sung.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:	MyungJoo Ham <myungjoo.ham@...sung.com>,
	David Cohen <david.a.cohen@...ux.intel.com>,
	Lu Baolu <baolu.lu@...ux.intel.com>,
	Mathias Nyman <mathias.nyman@...ux.intel.com>,
	Felipe Balbi <balbi@...com>, linux-usb@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCHv2 1/2] extcon: add driver for Intel USB mux

On 12/03/2015 12:29 PM, Heikki Krogerus wrote:

> Several Intel PCHs and SOCs have an internal mux that is
> used to share one USB port between USB Device Controller and
> xHCI. The mux is normally handled by System FW/BIOS, but not
> always. For those platforms where the FW does not take care
> of the mux, this driver is needed.
>
> Signed-off-by: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
[...]
> diff --git a/drivers/extcon/extcon-intel-usb.c b/drivers/extcon/extcon-intel-usb.c
> new file mode 100644
> index 0000000..3da6039
> --- /dev/null
> +++ b/drivers/extcon/extcon-intel-usb.c
> @@ -0,0 +1,118 @@
[...]
> +struct intel_usb_mux *intel_usb_mux_register(struct device *dev,
> +					     struct resource *r)
> +{
> +	struct intel_usb_mux *mux;
> +	int ret;
> +
> +	mux = kzalloc(sizeof(*mux), GFP_KERNEL);
> +	if (!mux)
> +		return ERR_PTR(-ENOMEM);
> +
> +	mux->regs = ioremap_nocache(r->start, resource_size(r));
> +	if (!mux->regs) {
> +		kfree(mux);
> +		return ERR_PTR(-ENOMEM);
> +	}
> +
> +	mux->cfg0_ctx = readl(mux->regs + INTEL_MUX_CFG0);
> +
> +	mux->edev.dev.parent = dev;
> +	mux->edev.supported_cable = intel_mux_cable;
> +
> +	ret = extcon_dev_register(&mux->edev);

    I don't see where are you calling extcon_set_cable_state() fot the 
"USB-HOST" cable...
This doesn't seem a legitimate extcon driver to me... :-/

> +	if (ret)
> +		goto err;
> +
> +	mux->edev.name = "intel_usb_mux";
> +	mux->edev.state = !!(readl(mux->regs + INTEL_MUX_CFG1) & CFG1_MODE);
> +
> +	/* An external source needs to tell us what to do */
> +	mux->nb.notifier_call = intel_usb_mux_notifier;
> +	ret = extcon_register_notifier(&mux->edev, EXTCON_USB_HOST, &mux->nb);

    So in reality this is an extcon client, not a provider? BTW, this API 
isn't recommended...

MBR, Sergei

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