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SubjectRE: [RFC PATCH v1 14/14] usb:cdns3: Feature for changing role
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>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@cadence.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@cadence.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.

>> + 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

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