From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <48921179.1080403@freescale.com> Date: Thu, 31 Jul 2008 14:24:41 -0500 From: Timur Tabi MIME-Version: 1.0 To: Wolfgang Grandegger Subject: Re: [PATCH] powerpc: i2c-mpc: make speed registers configurable via FDT References: <4889EFFE.2070201@grandegger.com> <4889FD1D.4010804@freescale.com> <20080727012722.GH12191@secretlab.ca> <4891A744.6060005@grandegger.com> <9e4733910807310849g7e5612dbk9536733e061af8ad@mail.gmail.com> <4891F4D8.9090905@grandegger.com> <4891FC3A.7040609@freescale.com> <20080731180959.GA29057@secretlab.ca> <489200B6.9060906@freescale.com> <20080731182810.GB29097@secretlab.ca> <48920607.5040606@freescale.com> <48921187.1090101@grandegger.com> In-Reply-To: <48921187.1090101@grandegger.com> Content-Type: text/plain; charset=ISO-8859-1 Cc: Scott Wood , Linux I2C , Linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Wolfgang Grandegger wrote: > No, the source clock is not identical for all 8[356]xx. Some use half or > even a third of the SOC clock frequency. The platform clock divided by 2 or 3 *is* the source clock to the I2C. That's what I'm talking about. > Linux must determine the real > source clock frequency somehow. We may introduce the SOC property > "i2c-clock-frequency", which could be fixed up by U-Boot or a pre-loader > (in case U-Boot is not used). Like for other frequency properties as well. That's what I'm proposing, but drop the "i2c-". -- Timur Tabi Linux kernel developer at Freescale