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usb: uhci: Add reset control support

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Some SoCs, such as the Aspeed AST2700, require the UHCI controller
to be taken out of reset before it can operate. Add optional reset
control support to the UHCI platform driver.

The driver now acquires an optional reset line from device tree,
deasserts it during probe, and asserts it again in the error path
and shutdown.

Signed-off-by: Ryan Chen <ryan_chen@aspeedtech.com>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/20250922052045.2421480-3-ryan_chen@aspeedtech.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ryan Chen 2025-09-22 13:20:43 +08:00 committed by Greg Kroah-Hartman
parent 19040e5626
commit 113ba4270a
2 changed files with 16 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
drivers/usb/host/uhci-hcd.h
View File

@ -445,6 +445,7 @@ struct uhci_hcd {
short load[MAX_PHASE]; /* Periodic allocations */
struct clk *clk; /* (optional) clock source */
struct reset_control *rsts; /* (optional) clock reset */
/* Reset host controller */
void (*reset_hc) (struct uhci_hcd *uhci);

17
drivers/usb/host/uhci-platform.c
View File

@ -11,6 +11,7 @@
#include <linux/of.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/reset.h>
static int uhci_platform_init(struct usb_hcd *hcd)
{
@ -132,17 +133,28 @@ static int uhci_hcd_platform_probe(struct platform_device *pdev)
goto err_rmr;
}
uhci->rsts = devm_reset_control_array_get_optional_shared(&pdev->dev);
if (IS_ERR(uhci->rsts)) {
ret = PTR_ERR(uhci->rsts);
goto err_clk;
}
ret = reset_control_deassert(uhci->rsts);
if (ret)
goto err_clk;
ret = platform_get_irq(pdev, 0);
if (ret < 0)
goto err_clk;
goto err_reset;
ret = usb_add_hcd(hcd, ret, IRQF_SHARED);
if (ret)
goto err_clk;
goto err_reset;
device_wakeup_enable(hcd->self.controller);
return 0;
err_reset:
reset_control_assert(uhci->rsts);
err_clk:
clk_disable_unprepare(uhci->clk);
err_rmr:
@ -156,6 +168,7 @@ static void uhci_hcd_platform_remove(struct platform_device *pdev)
struct usb_hcd *hcd = platform_get_drvdata(pdev);
struct uhci_hcd *uhci = hcd_to_uhci(hcd);
reset_control_assert(uhci->rsts);
clk_disable_unprepare(uhci->clk);
usb_remove_hcd(hcd);
usb_put_hcd(hcd);