Hello Alan,
On 16/07/2013 18:48, 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).
But it does print a warning in the system log, right?
Yes it does.
@@ -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");
+ }
Is this really what you want for backward compatibility?
Here are some proposition to remove the warning message:
1) replace it with a dev_info and change the message:
dev_info(&pdev->dev, "failed to get usb_clk (most likely using old
at91 clk implementation)\n");
2) drop the log and silently ignore the missing clk (I'm not a big fan
of this solution
as it may lead to some errors if we're using new clk implem and the
clock is really missing)
3) rework the current clk_set_rate function to accept clk_set_rate on
usb clk and add clk_lookup entries
for the usb clk (I'm not a big fan of this solution neither as this
modifications will only be used for a short time
until the transition to common clk framework is completed).
Alan Stern
Thanks for your review.
Best Regards,
Boris
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