i2c-mpc.c clock/speed

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?

Thanks in advance,

Roland.

Hi Roland,

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