From mboxrd@z Thu Jan 1 00:00:00 1970 From: b.brezillon@overkiz.com (boris brezillon) Date: Thu, 01 Aug 2013 17:14:50 +0200 Subject: [PATCH] USB: ohci-at91: add usb_clk for transition to common clk framework In-Reply-To: References: Message-ID: <51FA7B6A.80106@overkiz.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 01/08/2013 16:39, Alan Stern wrote: > On Thu, 1 Aug 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 adds 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 it). >> >> Signed-off-by: Boris BREZILLON >> @@ -163,6 +169,8 @@ static int usb_hcd_at91_probe(const struct hc_driver *driver, >> goto err5; >> } >> >> + uclk = clk_get(&pdev->dev, "usb_clk"); > What happens if uclk isn't found but it is needed? It will not fail but I guess the usb host won't work as the clock won't be correctly configured. I agree with you: this is not a good solution. Another option is to keep the previous version of this patch and put uclk handling in "#ifdef CONFIG_COMMON_CLK #endif" sections. Would this be acceptable ? > > Alan Stern >