[cip-dev] [PATCH 4.19.y 13/17] usb: gadget: udc: renesas_usb3: add a safety connection way for forced_b_device

Fabrizio Castro
2019-04-24T17:20:36Z

From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>

commit ceb94bc52c437463f0903e61060a94a2226fb672 upstream.

This patch adds a safety connection way for "forced_b_device" with
"workaround_for_vbus" like below:

< Example for R-Car E3 Ebisu >
# modprobe <any usb gadget driver>
# echo 1 > /sys/kernel/debug/ee020000.usb/b_device
(connect a usb cable to host side.)
# echo 2 > /sys/kernel/debug/ee020000.usb/b_device

Previous code should have connected a usb cable before the "b_device"
is set to 1 on the Ebisu board. However, if xHCI driver on the board
is probed, it causes some troubles:
- Conflicts USB VBUS/signals between the board and another host.
- "Cannot enable. Maybe the USB cable is bad?" might happen on
both the board and another host with a usb hub.
- Cannot enumerate a usb gadget correctly because an interruption
of VBUS change happens unexpectedly.

Reported-by: Kazuya Mizuguchi <kazuya.mizuguchi.ks@renesas.com>
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
---
drivers/usb/gadget/udc/renesas_usb3.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/gadget/udc/renesas_usb3.c b/drivers/usb/gadget/udc/renesas_usb3.c
index cdffbd1..6e34f95 100644
--- a/drivers/usb/gadget/udc/renesas_usb3.c
+++ b/drivers/usb/gadget/udc/renesas_usb3.c
@@ -358,6 +358,7 @@ struct renesas_usb3 {
bool extcon_host; /* check id and set EXTCON_USB_HOST */
bool extcon_usb; /* check vbus and set EXTCON_USB */
bool forced_b_device;
+ bool start_to_connect;
};

#define gadget_to_renesas_usb3(_gadget) \
@@ -476,7 +477,8 @@ static void usb3_init_axi_bridge(struct renesas_usb3 *usb3)
static void usb3_init_epc_registers(struct renesas_usb3 *usb3)
{
usb3_write(usb3, ~0, USB3_USB_INT_STA_1);
- usb3_enable_irq_1(usb3, USB_INT_1_VBUS_CNG);
+ if (!usb3->workaround_for_vbus)
+ usb3_enable_irq_1(usb3, USB_INT_1_VBUS_CNG);
}

static bool usb3_wakeup_usb2_phy(struct renesas_usb3 *usb3)
@@ -700,8 +702,7 @@ static void usb3_mode_config(struct renesas_usb3 *usb3, bool host, bool a_dev)
usb3_set_mode_by_role_sw(usb3, host);
usb3_vbus_out(usb3, a_dev);
/* for A-Peripheral or forced B-device mode */
- if ((!host && a_dev) ||
- (usb3->workaround_for_vbus && usb3->forced_b_device))
+ if ((!host && a_dev) || usb3->start_to_connect)
usb3_connect(usb3);
spin_unlock_irqrestore(&usb3->lock, flags);
}
@@ -2432,7 +2433,11 @@ static ssize_t renesas_usb3_b_device_write(struct file *file,
if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
return -EFAULT;

- if (!strncmp(buf, "1", 1))
+ usb3->start_to_connect = false;
+ if (usb3->workaround_for_vbus && usb3->forced_b_device &&
+ !strncmp(buf, "2", 1))
+ usb3->start_to_connect = true;
+ else if (!strncmp(buf, "1", 1))
usb3->forced_b_device = true;
else
usb3->forced_b_device = false;
@@ -2440,7 +2445,7 @@ static ssize_t renesas_usb3_b_device_write(struct file *file,
if (usb3->workaround_for_vbus)
usb3_disconnect(usb3);

- /* Let this driver call usb3_connect() anyway */
+ /* Let this driver call usb3_connect() if needed */
usb3_check_id(usb3);

return count;
--
2.7.4