Re: [PATCH v3 6/7] USB: ohci-at91: add usb_clk for transition tocommon clk framework

From: boris brezillon
Date: Wed Jul 17 2013 - 11:55:43 EST


On 17/07/2013 17:33, Alan Stern wrote:
On Tue, 16 Jul 2013, Boris BREZILLON wrote:

The AT91 PMC (Power Management Controller) provides an USB clock used by
USB Full Speed host (ohci) and USB Full Speed device (udc).
The usb drivers (ohci and udc) must configure this clock to 48Mhz.
This configuration was formely done in mach-at91/clock.c, but this
implementation will be removed when moving to common clk framework.

This patch add support for usb clock retrieval and configuration, and is
backward compatible with the current at91 clk implementation (if usb clk
is not found, it does not configure/enable the usb clk).
This does not take into account any of the changes you discussed with
Russell King and me -- it is exactly the same as the previous version.
Sorry, I don't understand. I didn't send any new version since yesterday.

I'm sending it right now and it's part of the
"ARM: at91: move to common clk framework" series (as discussed with you).


@@ -144,6 +150,11 @@ static int usb_hcd_at91_probe(const struct hc_driver *driver,
goto err2;
}
+ uclk = clk_get(&pdev->dev, "usb_clk");
+ if (IS_ERR(uclk)) {
+ uclk = NULL;
+ dev_warn(&pdev->dev, "failed to get usb_clk\n");
+ }
iclk = clk_get(&pdev->dev, "ohci_clk");
if (IS_ERR(iclk)) {
dev_err(&pdev->dev, "failed to get ohci_clk\n");
@@ -212,10 +223,11 @@ static void usb_hcd_at91_remove(struct usb_hcd *hcd,
release_mem_region(hcd->rsrc_start, hcd->rsrc_len);
usb_put_hcd(hcd);
+ clk_put(uclk);
What will clk_put() do when uclk is NULL?

Alan Stern


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