Messages in this thread | | | Date | Tue, 16 Jul 2013 19:08:12 +0200 | From | boris brezillon <> | Subject | Re: [PATCH v3 6/7] USB: ohci-at91: add usb_clk for transition to common clk framework |
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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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