Hi Roland, On Wed, 05 Mar 2014 10:29:28 +0100 Roland Stigge <stigge@xxxxxxxxx> wrote: > Hi, > > in mpc_i2c_get_fdr_8xxx(), we have: > > ... > if (of_device_is_compatible(node, "fsl,mpc8544-i2c")) > prescaler = mpc_i2c_get_sec_cfg_8xxx() ? 3 : 2; > if (!prescaler) > prescaler = 1; > ... > > By restricting to "fsl,mpc8544-i2c", measured I2C speed on fsl p2020 is > only half as fast as configured (w/ prescaler = 1). > > In DT (arch/powerpc/boot/dts/fsl/pq3-i2c-0.dtsi), we have "fsl-i2c" > (i.e., generic), for Freescale boards. > > What would be the best solution here? Additional "compatible" strings, > e.g. "fsl,p1020-i2c" and adjusting i2c-mpc.c and DT? Or removing the > restriction to "fsl,mpc8544-i2c", i.e. calling > mpc_i2c_get_sec_cfg_8xxx() unconditionally? we can't remove this mpc8544e specific check here, it checks the SEC_CFG bit 24 in the PORDEVSR2 register, on other mpc8xxx cpus this register is either not present or the meaning of the bit 24 in this register is different. Adding "fsl,p1020-i2c" compatible and adjusting the driver would be okay. Thanks, Anatolij -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
