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Date: Thu, 8 Nov 2018 16:22:56 +0200
From: Roger Quadros <rogerq@...com>
To: Pawel Laszczak <pawell@...ence.com>,
"gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>
CC: "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Alan Douglas <adouglas@...ence.com>,
"jbergsagel@...com" <jbergsagel@...com>,
"peter.chen@....com" <peter.chen@....com>,
Pawel Jez <pjez@...ence.com>, Rahul Kumar <kurahul@...ence.com>
Subject: Re: [RFC PATCH v1 14/14] usb:cdns3: Feature for changing role
On 08/11/18 13:51, Pawel Laszczak wrote:
>> On 03/11/18 19:51, Pawel Laszczak wrote:
>>> Patch adds feature that allow to change role from user space.
>>>
>>> Signed-off-by: Pawel Laszczak <pawell@...ence.com>
>>> ---
>>> drivers/usb/cdns3/Makefile | 2 +-
>>> drivers/usb/cdns3/core.c | 2 +
>>> drivers/usb/cdns3/debugfs.c | 94 +++++++++++++++++++++++++++++++++++++
>>> drivers/usb/cdns3/drd.h | 3 ++
>>> 4 files changed, 100 insertions(+), 1 deletion(-)
>>> create mode 100644 drivers/usb/cdns3/debugfs.c
>>>
>>> diff --git a/drivers/usb/cdns3/Makefile b/drivers/usb/cdns3/Makefile
>>> index 34e60d03c4ec..08e6cdbebd46 100644
>>> --- a/drivers/usb/cdns3/Makefile
>>> +++ b/drivers/usb/cdns3/Makefile
>>> @@ -1,7 +1,7 @@
>>> obj-$(CONFIG_USB_CDNS3) += cdns3.o
>>> obj-$(CONFIG_USB_CDNS3_PCI_WRAP) += cdns3-pci.o
>>>
>>> -cdns3-y := core.o drd.o
>>> +cdns3-y := core.o drd.o debugfs.o
>>> cdns3-$(CONFIG_USB_CDNS3_GADGET) += gadget.o ep0.o debug.o
>>> cdns3-$(CONFIG_USB_CDNS3_HOST) += host.o
>>> cdns3-pci-y := cdns3-pci-wrap.o
>>> diff --git a/drivers/usb/cdns3/core.c b/drivers/usb/cdns3/core.c
>>> index 20ae9e76940e..4012f1007da9 100644
>>> --- a/drivers/usb/cdns3/core.c
>>> +++ b/drivers/usb/cdns3/core.c
>>> @@ -309,6 +309,7 @@ static int cdns3_probe(struct platform_device *pdev)
>>> if (ret)
>>> goto err4;
>>>
>>> + cdns3_debugfs_init(cdns);
>>> device_set_wakeup_capable(dev, true);
>>> pm_runtime_set_active(dev);
>>> pm_runtime_enable(dev);
>>> @@ -346,6 +347,7 @@ static int cdns3_remove(struct platform_device *pdev)
>>> pm_runtime_get_sync(&pdev->dev);
>>> pm_runtime_disable(&pdev->dev);
>>> pm_runtime_put_noidle(&pdev->dev);
>>> + cdns3_debugfs_exit(cdns);
>>> cdns3_remove_roles(cdns);
>>> usb_phy_shutdown(cdns->usbphy);
>>>
>>> diff --git a/drivers/usb/cdns3/debugfs.c b/drivers/usb/cdns3/debugfs.c
>>> new file mode 100644
>>> index 000000000000..d4871bc1a69d
>>> --- /dev/null
>>> +++ b/drivers/usb/cdns3/debugfs.c
>>> @@ -0,0 +1,94 @@
>>> +// SPDX-License-Identifier: GPL-2.0
>>> +/*
>>> + * Cadence USBSS DRD Controller DebugFS filer.
>>> + *
>>> + * Copyright (C) 2018 Cadence.
>>> + *
>>> + * Author: Pawel Laszczak <pawell@...ence.com>
>>> + */
>>> +
>>> +#include <linux/types.h>
>>> +#include <linux/debugfs.h>
>>> +#include <linux/seq_file.h>
>>> +#include <linux/uaccess.h>
>>> +
>>> +#include "core.h"
>>> +#include "gadget.h"
>>> +
>>> +static int cdns3_mode_show(struct seq_file *s, void *unused)
>>> +{
>>> + struct cdns3 *cdns = s->private;
>>> +
>>> + switch (cdns->role) {
>>> + case CDNS3_ROLE_HOST:
>>> + seq_puts(s, "host\n");
>>> + break;
>>> + case CDNS3_ROLE_GADGET:
>>> + seq_puts(s, "device\n");
>>> + break;
>>> + case CDNS3_ROLE_OTG:
>>> + case CDNS3_ROLE_END:
>>> + seq_puts(s, "otg\n");
>>> + break;
>>> + default:
>>> + seq_puts(s, "UNKNOWN mode\n");
>>> + }
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int cdns3_mode_open(struct inode *inode, struct file *file)
>>> +{
>>> + return single_open(file, cdns3_mode_show, inode->i_private);
>>> +}
>>> +
>>> +static ssize_t cdns3_mode_write(struct file *file,
>>> + const char __user *ubuf,
>>> + size_t count, loff_t *ppos)
>>> +{
>>> + struct seq_file *s = file->private_data;
>>> + struct cdns3 *cdns = s->private;
>>> + u32 mode = 0;
>>> + char buf[32];
>>> +
>>> + if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
>>> + return -EFAULT;
>>> +
>>> + if (!strncmp(buf, "host", 4))
>>> + mode = USB_DR_MODE_HOST;
>>> +
>>> + if (!strncmp(buf, "device", 6))
>>> + mode = USB_DR_MODE_PERIPHERAL;
>>> +
>>> + if (!strncmp(buf, "otg", 3))
>>> + mode = USB_DR_MODE_OTG;
>>> +
>>> + cdns->desired_role = mode;
>>> + queue_work(system_freezable_wq, &cdns->role_switch_wq);
>>
>> If we start with OTG mode and user says change mode to device will we still
>> switch to host based on ID pin change?
>>
>> If it does then this isn't working correctly.
>> We need to stop processing ID interrupts and keep the role static till
>> the user switches it back to otg.
>
> Switching role form user space will limited driver only to selected mode.
> Only for USB_DR_MODE_OTG driver should base on ID pin.
> That's my intension.
>
User space setting should override ID if it was OTG mode. At least this is how
it is for dwc3. That way it is useful for testing role swap.
cheers,
-roger
>>> + return count;
>>> +}
>>> +
>>> +static const struct file_operations cdns3_mode_fops = {
>>> + .open = cdns3_mode_open,
>>> + .write = cdns3_mode_write,
>>> + .read = seq_read,
>>> + .llseek = seq_lseek,
>>> + .release = single_release,
>>> +};
>>> +
>>> +void cdns3_debugfs_init(struct cdns3 *cdns)
>>> +{
>>> + struct dentry *root;
>>> +
>>> + root = debugfs_create_dir(dev_name(cdns->dev), NULL);
>>> + cdns->root = root;
>>> + if (IS_ENABLED(CONFIG_USB_CDNS3_GADGET) &&
>>> + IS_ENABLED(CONFIG_USB_CDNS3_HOST))
>>> + debugfs_create_file("mode", 0644, root, cdns,
>>> + &cdns3_mode_fops);
>>> +}
>>> +
>>> +void cdns3_debugfs_exit(struct cdns3 *cdns)
>>> +{
>>> + debugfs_remove_recursive(cdns->root);
>>> +}
>>> diff --git a/drivers/usb/cdns3/drd.h b/drivers/usb/cdns3/drd.h
>>> index 85731f3b693c..5344290c76f2 100644
>>> --- a/drivers/usb/cdns3/drd.h
>>> +++ b/drivers/usb/cdns3/drd.h
>>> @@ -119,4 +119,7 @@ int cdns3_drd_probe(struct cdns3 *cdns);
>>> void cdns3_set_hw_mode(struct cdns3 *cdns, u32 mode);
>>> irqreturn_t cdns3_drd_irq(struct cdns3 *cdns);
>>>
>>> +void cdns3_debugfs_init(struct cdns3 *cdns);
>>> +void cdns3_debugfs_exit(struct cdns3 *cdns);
>>> +
>>> #endif /* __LINUX_CDNS3_DRD */
>>>
>>
>> cheers,
>> -roger
>> --
>> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
>> Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
>
>
> Thanks,
> Cheers,
> Pawel
>
--
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
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