[U-Boot] [PATCH v2 1/2] usb: gadget: fotg210: add w1c interrupt status support

[Kuo-Jung Su <dantesu@gmail.com>]

From: Kuo-Jung Su <dantesu@faraday-tech.com>

Since hardware revision 1.11.0, the following interrupt status
registers are now W1C (i.e., write 1 clear):

1. Interrupt Source Group 0 Register (0x144) (EP0 Abort: BIT5)
2. Interrupt Source Group 2 Register (0x14C) (All bits)

And before revision 1.11.0, these registers are all R/W.
Which means software must write a 0 to clear the status.

Signed-off-by: Kuo-Jung Su <dantesu@faraday-tech.com>
CC: Marek Vasut <marex@denx.de>
---
Changes for v2:
	- By writting 1 then 0 to get rid of the use of
	  CONFIG_USB_GADGET_FOTG210_ISRW1C.
	  Thanks for Marek's comments.

 drivers/usb/gadget/fotg210.c |   14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/usb/gadget/fotg210.c b/drivers/usb/gadget/fotg210.c
index 6e19db1..cc5c507 100644
--- a/drivers/usb/gadget/fotg210.c
+++ b/drivers/usb/gadget/fotg210.c
@@ -847,6 +847,13 @@ int usb_gadget_handle_interrupts(void)
 	/* CX interrupts */
 	if (gisr & GISR_GRP0) {
 		st = readl(&regs->gisr0);
+		/*
+		 * Write 1 and then 0 works for both W1C & RW.
+		 *
+		 * HW v1.11.0+: It's a W1C register (write 1 clear)
+		 * HW v1.10.0-: It's a R/W register (write 0 clear)
+		 */
+		writel(st & GISR0_CXABORT, &regs->gisr0);
 		writel(0, &regs->gisr0);

 		if (st & GISR0_CXERR)
@@ -873,6 +880,13 @@ int usb_gadget_handle_interrupts(void)
 	/* Device Status Interrupts */
 	if (gisr & GISR_GRP2) {
 		st = readl(&regs->gisr2);
+		/*
+		 * Write 1 and then 0 works for both W1C & RW.
+		 *
+		 * HW v1.11.0+: It's a W1C register (write 1 clear)
+		 * HW v1.10.0-: It's a R/W register (write 0 clear)
+		 */
+		writel(st, &regs->gisr2);
 		writel(0, &regs->gisr2);

 		if (st & GISR2_RESET)
--
1.7.9.5