From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kumar Gala Subject: Re: [PATCH v11 4/5] powerpc: Add flexcan device support for p1010rdb. Date: Wed, 10 Aug 2011 23:46:27 -0500 Message-ID: <634AB7A6-1CDA-41B3-8A5D-01F29EF01521@kernel.crashing.org> References: <1312993670-23999-1-git-send-email-holt@sgi.com> <1312993670-23999-5-git-send-email-holt@sgi.com> <8E5FA886-038D-4DF4-8A54-DD60188A21A2@kernel.crashing.org> <4E42CB01.7030700@grandegger.com> Mime-Version: 1.0 (Apple Message framework v1084) Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, U Bhaskar-B22300 , socketcan-core-0fE9KPoRgkgATYTw5x5z8w@public.gmane.org, Marc Kleine-Budde , PPC list To: Wolfgang Grandegger Return-path: In-Reply-To: <4E42CB01.7030700-5Yr1BZd7O62+XT7JhA+gdA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: socketcan-core-bounces-0fE9KPoRgkgATYTw5x5z8w@public.gmane.org Errors-To: socketcan-core-bounces-0fE9KPoRgkgATYTw5x5z8w@public.gmane.org List-Id: netdev.vger.kernel.org On Aug 10, 2011, at 1:16 PM, Wolfgang Grandegger wrote: > On 08/10/2011 07:01 PM, Kumar Gala wrote: >> >> On Aug 10, 2011, at 11:27 AM, Robin Holt wrote: >> >>> I added a simple clock source for the p1010rdb so the flexcan driver >>> could determine a clock frequency. The p1010 flexcan device only has >>> an oscillator of system bus frequency divided by 2. >>> >>> Signed-off-by: Robin Holt >>> Acked-by: Marc Kleine-Budde , >>> Acked-by: Wolfgang Grandegger , >>> Cc: U Bhaskar-B22300 >>> Cc: socketcan-core-0fE9KPoRgkgATYTw5x5z8w@public.gmane.org, >>> Cc: netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, >>> Cc: PPC list >>> Cc: Kumar Gala >>> --- >>> arch/powerpc/platforms/85xx/Kconfig | 2 + >>> arch/powerpc/platforms/85xx/Makefile | 2 + >>> arch/powerpc/platforms/85xx/clock.c | 52 ++++++++++++++++++++++++++++++++ >>> arch/powerpc/platforms/85xx/p1010rdb.c | 8 +++++ >>> 4 files changed, 64 insertions(+), 0 deletions(-) >>> create mode 100644 arch/powerpc/platforms/85xx/clock.c >> >> I dont understand how mpc85xx_clk_functions() ends up being associated with the frequency the flexcan is running at. > > The function mpc85xx_clk_get_rate() returns "fsl_get_sys_freq() / 2" for > Flexcan devices. > >> This either seems to global or I'm missing something. > > This patch extends the existing Flexcan platform driver for ARM for the > PowerPC using the device tree. Due to the nice integration of the device > tree (of-platform) into the platform driver and devices, the difference > are quite small (see patches 1..3). Apart from the endianess issue, only > the clock needs to be handled in a common way. As ARM already uses the > clk interface, we found it straight-forward to implement it for the > P1010, or more general for the 85xx, as well, instead of using an > additional helper function. I see, that. What concerns me is there are numerous clocks / frequencies that exist inside a MPC85xx/P1010 SOC. The code I'm seeing does NOT seem to do anything to relate this clock JUST to the flexcan. >> I still think the clk / freq info should be in the device tree and handled in the driver and NOT arch/powerpc platform code. > > If I understand you correctly, you want the boot-loader to provide the > relevant information by fixing up the device tree, which then can be > handled arch-independently by the driver, right? Yes, that is part of what I want. - k