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usb: host: xhci-plat: add clock support

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Some platforms (such as the Armada 38x ones) can gate the clock of
their USB controller. This patch adds the support for one clock in
xhci-plat, by enabling it during probe and disabling it on remove.

To achieve this, it adds a 'struct clk *' member in xhci_hcd. While
only used for now in xhci-plat, it might be used by other drivers in
the future. Moreover, the xhci_hcd structure already holds other
members such as msix_count and msix_entries, which are MSI-X specific,
and therefore only used by xhci-pci.

Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Felipe Balbi <balbi@ti.com>
Acked-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Gregory CLEMENT 2014-05-15 12:17:32 +02:00 committed by Greg Kroah-Hartman
parent 48157bb97f
commit 4718c17740
2 changed files with 25 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

24
drivers/usb/host/xhci-plat.c
View file

@ -11,6 +11,7 @@
* version 2 as published by the Free Software Foundation.
*/
#include <linux/clk.h>
#include <linux/dma-mapping.h>
#include <linux/module.h>
#include <linux/of.h>
@ -91,6 +92,7 @@ static int xhci_plat_probe(struct platform_device *pdev)
struct xhci_hcd *xhci;
struct resource *res;
struct usb_hcd *hcd;
struct clk *clk;
int ret;
int irq;
@ -137,14 +139,27 @@ static int xhci_plat_probe(struct platform_device *pdev)
goto release_mem_region;
}
/*
* Not all platforms have a clk so it is not an error if the
* clock does not exists.
*/
clk = devm_clk_get(&pdev->dev, NULL);
if (!IS_ERR(clk)) {
ret = clk_prepare_enable(clk);
if (ret)
goto unmap_registers;
}
ret = usb_add_hcd(hcd, irq, IRQF_SHARED);
if (ret)
goto unmap_registers;
goto disable_clk;
device_wakeup_enable(hcd->self.controller);
/* USB 2.0 roothub is stored in the platform_device now. */
hcd = platform_get_drvdata(pdev);
xhci = hcd_to_xhci(hcd);
xhci->clk = clk;
xhci->shared_hcd = usb_create_shared_hcd(driver, &pdev->dev,
dev_name(&pdev->dev), hcd);
if (!xhci->shared_hcd) {
@ -173,6 +188,10 @@ static int xhci_plat_probe(struct platform_device *pdev)
dealloc_usb2_hcd:
usb_remove_hcd(hcd);
disable_clk:
if (!IS_ERR(clk))
clk_disable_unprepare(clk);
unmap_registers:
iounmap(hcd->regs);
@ -189,11 +208,14 @@ static int xhci_plat_remove(struct platform_device *dev)
{
struct usb_hcd *hcd = platform_get_drvdata(dev);
struct xhci_hcd *xhci = hcd_to_xhci(hcd);
struct clk *clk = xhci->clk;
usb_remove_hcd(xhci->shared_hcd);
usb_put_hcd(xhci->shared_hcd);
usb_remove_hcd(hcd);
if (!IS_ERR(clk))
clk_disable_unprepare(clk);
iounmap(hcd->regs);
release_mem_region(hcd->rsrc_start, hcd->rsrc_len);
usb_put_hcd(hcd);

2
drivers/usb/host/xhci.h
View file

@ -1472,6 +1472,8 @@ struct xhci_hcd {
/* msi-x vectors */
int msix_count;
struct msix_entry *msix_entries;
/* optional clock */
struct clk *clk;
/* data structures */
struct xhci_device_context_array *dcbaa;
struct xhci_ring *cmd_ring;