From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marc Dietrich Subject: Re: [PATCH 4/5 V2] ARM: tegra: paz00: add clocks required for usb operation Date: Tue, 9 Aug 2011 21:18:43 +0200 Message-ID: <201108092118.43724.marvin24@gmx.de> References: <201108092029.17546.marvin24@gmx.de> Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Olof Johansson Cc: Colin Cross , linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: linux-tegra@vger.kernel.org Hi Olof, On Tuesday 09 August 2011 20:30:47 Olof Johansson wrote: > On Tue, Aug 9, 2011 at 11:29 AM, Marc Dietrich wrote: > > > > These clocks are required for usb operation. > > --- > > arch/arm/mach-tegra/board-paz00.c | 6 ++++++ > > 1 files changed, 6 insertions(+), 0 deletions(-) > > > > diff --git a/arch/arm/mach-tegra/board-paz00.c b/arch/arm/mach-tegra/board- paz00.c > > index 45111f6..89a3dda 100644 > > --- a/arch/arm/mach-tegra/board-paz00.c > > +++ b/arch/arm/mach-tegra/board-paz00.c > > @@ -145,6 +145,12 @@ static __initdata struct tegra_clk_init_table paz00_clk_init_table[] = { > > /* name parent rate enabled */ > > { "uarta", "pll_p", 216000000, true }, > > { "uartd", "pll_p", 216000000, true }, > > + > > + { "pll_p_out4", "pll_p", 24000000, true }, > > + { "usbd", "clk_m", 12000000, true }, > > + { "usb2", "clk_m", 12000000, true }, > > + { "usb3", "clk_m", 12000000, true }, > > Do they all have to be enabled here? Setting the parent and rate makes > sense, but you shouldn't have to enable them. usb also works with all three usb* clocks set to disabled (they are even not required to be listed there at all). Honestly, the whole clock setup is a little obscure to me. Can these clocks be safly disabled in the clock table and hope that the ehci host driver will enable them if required? Also independent to what the bootloader does, which I don't know? I'm asking because we may switch from the proprietary bootloader (fastboot?) to u-boot in the near future. Marc