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From: Pawel Laszczak <pawell@cadence.com>
To: Felipe Balbi <felipe.balbi@linux.intel.com>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>
Cc: "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
	"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
	"hdegoede@redhat.com" <hdegoede@redhat.com>,
	"heikki.krogerus@linux.intel.com"
	<heikki.krogerus@linux.intel.com>,
	"robh+dt@kernel.org" <robh+dt@kernel.org>,
	"rogerq@ti.com" <rogerq@ti.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"jbergsagel@ti.com" <jbergsagel@ti.com>,
	"nsekhar@ti.com" <nsekhar@ti.com>, "nm@ti.com" <nm@ti.com>,
	Suresh Punnoose <sureshp@cadence.com>,
	"peter.chen@nxp.com" <peter.chen@nxp.com>,
	Jayshri Dajiram Pawar <jpawar@cadence.com>,
	Rahul Kumar <kurahul@cadence.com>
Subject: RE: [PATCH v9 5/6] usb:cdns3 Add Cadence USB3 DRD Driver
Date: Wed, 10 Jul 2019 08:25:08 +0000
Message-ID: <BYAPR07MB47090E2221C96D0B8178235CDDF00@BYAPR07MB4709.namprd07.prod.outlook.com> (raw)
In-Reply-To: <BYAPR07MB4709EF3753AC0B87606B1182DDF70@BYAPR07MB4709.namprd07.prod.outlook.com>

Hi Felipe

>>> +
>>> +static int cdns3_idle_init(struct cdns3 *cdns)
>>> +{
>>> +	struct cdns3_role_driver *rdrv;
>>> +
>>> +	rdrv = devm_kzalloc(cdns->dev, sizeof(*rdrv), GFP_KERNEL);
>>> +	if (!rdrv)
>>> +		return -ENOMEM;
>>> +
>>> +	rdrv->start = cdns3_idle_role_start;
>>> +	rdrv->stop = cdns3_idle_role_stop;
>>> +	rdrv->state = CDNS3_ROLE_STATE_INACTIVE;
>>> +	rdrv->suspend = NULL;
>>> +	rdrv->resume = NULL;
>>> +	rdrv->name = "idle";
>>
>>why don't you use the mux framework for this? This looks a bit fishy
>>too. Why do you have your own driver registration structure for your
>>driver only?
>>
>
>I assume you mean interface defined in include/linux/usb/role.h.
>It's quite new framework and probably was added after I've start implementing cdns3 driver.
>At first glance it's look that I could use it.

I've started integrating driver with role switch framework.  

Even if I use role switch interface , I still need this internal driver registration. 
It's convenient to use fallowing structure. 

struct cdns3_role_driver {
	int (*start)(struct cdns3 *cdns);
	void (*stop)(struct cdns3 *cdns);
	int (*suspend)(struct cdns3 *cdns, bool do_wakeup);
	int (*resume)(struct cdns3 *cdns, bool hibernated);
	const char *name;
#define CDNS3_ROLE_STATE_INACTIVE	0
#define CDNS3_ROLE_STATE_ACTIVE		1
	int state;
};

Driver can supports: only Host, only Device or DRD - depending on configuration.

If current configuration support only Host then driver assigns:
	rdrv_host->start	= __cdns3_host_init;
	rdrv_host->stop	= cdns3_host_exit;

	cdns->roles[CDNS3_ROLE_HOST]  = 	rdrv_host
	cdns->roles[CDNS3_ROLE_GADGET	= NULL;
if support only Device then:
	rdrv_dev->start	= __cdns3_ gadget _init;
	rdrv_dev->stop	= cdns3_ gadget _exit;
	cdns->roles[CDNS3_ROLE_HOST]	= NULL;
for DRD:
	cdns->roles[CDNS3_ROLE_HOST = rdrv_host;
	cdns->roles[CDNS3_ROLE_GADGET] = rdrv_dev;

So for DRD we will have both filled, but for only Device or Host we 
will have filled single element of array. 

With such array we can easily start/stop role by 
	if (!cdns->roles[role])
		not supported by configuration.
	else
		cdns->roles[role]->start / cdns->roles[role]->stop

I don't need any extra: switch instruction or #ifdef statement. 

The name cdns3_role_driver can be misleading. 
Driver doesn't register the driver but rather the interface to Device/Host. 

Maybe I should change this name to  cdns3_role_interface or cdns3_role_action ?

Now I have my private enum:
enum cdns3_roles {
	CDNS3_ROLE_IDLE = 0,
	CDNS3_ROLE_HOST,
	CDNS3_ROLE_GADGET,
	CDNS3_ROLE_END,
};

I think I could replace it with usb_role. I need one extra state for IDLE but
Instead of CDNS3_ROLE_IDLE I can use USB_ROLE_NONE.

It should little simplify the driver and improve readability. 

Do you have any comments or suggestion ?

Cheers, 
Pawel

>
>>> +
>>> +	cdns->roles[CDNS3_ROLE_IDLE] = rdrv;
>>> +
>>> +	return 0;
>>> +}
>>> +


  parent reply index

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-05 10:57 [PATCH v9 0/6] Introduced new Cadence USBSS " Pawel Laszczak
2019-07-05 10:57 ` [PATCH v9 1/6] dt-bindings: add binding for USBSS-DRD controller Pawel Laszczak
2019-07-05 10:57 ` [PATCH v9 2/6] usb:gadget Separated decoding functions from dwc3 driver Pawel Laszczak
2019-07-05 11:27   ` Greg KH
2019-07-05 11:39     ` Pawel Laszczak
2019-07-05 11:49       ` Greg KH
2019-07-05 12:03         ` Pawel Laszczak
2019-07-05 11:39   ` Felipe Balbi
2019-07-05 11:44     ` Pawel Laszczak
2019-08-07 10:17       ` Roger Quadros
2019-08-07 10:22         ` Felipe Balbi
2019-08-08  3:07           ` Pawel Laszczak
2019-07-05 10:57 ` [PATCH v9 3/6] usb:gadget Patch simplify usb_decode_set_clear_feature function Pawel Laszczak
2019-07-05 10:57 ` [PATCH v9 4/6] usb:gadget Simplify usb_decode_get_set_descriptor function Pawel Laszczak
2019-07-05 10:57 ` [PATCH v9 5/6] usb:cdns3 Add Cadence USB3 DRD Driver Pawel Laszczak
2019-07-05 11:55   ` Felipe Balbi
2019-07-07 17:56     ` Pawel Laszczak
2019-07-08  6:29       ` Felipe Balbi
2019-07-08 10:59         ` Pawel Laszczak
2019-07-08 11:15           ` Felipe Balbi
2019-07-08 11:45             ` Pawel Laszczak
2019-07-08 11:59               ` Felipe Balbi
2019-07-08 12:39                 ` Pawel Laszczak
2019-07-09  4:23         ` Pawel Laszczak
2019-07-09  6:36           ` Felipe Balbi
2019-07-09  7:07             ` Pawel Laszczak
2019-07-09  7:22               ` Felipe Balbi
2019-07-09  7:29                 ` Pawel Laszczak
2019-07-10  8:25       ` Pawel Laszczak [this message]
2019-07-08  7:11   ` Felipe Balbi
2019-07-15 11:00     ` Pawel Laszczak
2019-08-07 10:34       ` Felipe Balbi
2019-08-10 20:39         ` Pawel Laszczak
2019-08-12  1:55           ` Peter Chen
2019-08-12  4:43             ` Pawel Laszczak
2019-08-12  5:24           ` Felipe Balbi
2019-08-12  7:13             ` Pawel Laszczak
2019-08-12  8:19               ` Felipe Balbi
2019-08-12  9:13                 ` Pawel Laszczak
2019-08-12  9:45                   ` Felipe Balbi
2019-08-12 10:26                     ` Pawel Laszczak
2019-08-12 10:34                       ` Felipe Balbi
2019-08-12 14:20                         ` Alan Stern
2019-07-05 10:57 ` [PATCH v9 6/6] usb:cdns3 Fix for stuck packets in on-chip OUT buffer Pawel Laszczak

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