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    SubjectRe: [PATCH take2] [POWERPC] i2c: adds support for i2c bus on 8xx
    Hi Scott,

    > Do we really need to be adding features for arch/ppc at this point? It'll
    > be going away in June. arch/ppc-specific things outside of arch/ppc itself
    > will also be more likely to be missed in the removal.
    >
    > Also, please post inline rather than as an attachment; attachments are
    > harder to quote in a reply.
    >

    OK. I'll remove the ARC=ppc parts.

    >> diff --git a/arch/powerpc/boot/dts/mpc885ads.dts b/arch/powerpc/boot/dts/mpc885ads.dts
    >> index 8848e63..a526c02 100644
    >> --- a/arch/powerpc/boot/dts/mpc885ads.dts
    >> +++ b/arch/powerpc/boot/dts/mpc885ads.dts
    >> @@ -213,6 +213,15 @@
    >> fsl,cpm-command = <0080>;
    >> linux,network-index = <2>;
    >> };
    >> +
    >> + i2c@860 {
    >> + device_type = "i2c";
    >>
    >
    > No device_type.
    >

    Why? Documentation/powerpc/booting-without-of.txt says for I2C interfaces
    device_type is required and should be "i2c". Is this no longer true?

    > Should be fsl,cpm-i2c. Is cpm2 i2c the same? If not, it should be
    > fsl,cpm1-i2c. It's probably best to specify it anyway, along with
    > fsl,mpc885-i2c.
    >

    CPM2 i2c seems to be the same. However, i have no way to test this.

    >> +#ifdef CONFIG_I2C_8XX
    >> + setbits32(&mpc8xx_immr->im_cpm.cp_pbpar, 0x00000030);
    >> + setbits32(&mpc8xx_immr->im_cpm.cp_pbdir, 0x00000030);
    >> + setbits16(&mpc8xx_immr->im_cpm.cp_pbodr, 0x0030);
    >> +#endif
    >>
    >
    > Please add this to mpc885ads_pins, rather than poking the registers
    > directly. The relevant lines are:
    >
    > {CPM_PORTB, 26, CPM_PIN_OUTPUT},
    > {CPM_PORTB, 27, CPM_PIN_OUTPUT},
    >

    I noticed cpm1_set_pin32, but this function don't seem to set the
    odr register. Will this be added? Then it would be:

    {CPM_PORTB, 26, CPM_PIN_OUTPUT | CPM_PIN_OPENDRAIN},
    {CPM_PORTB, 27, CPM_PIN_OUTPUT | CPM_PIN_OPENDRAIN},


    >> + /* Select an arbitrary address. Just make sure it is unique.
    >> + */
    >> + out_8(&i2c->i2c_i2add, 0xfe);
    >>
    >
    > It's a 7-bit address... and are you sure that 0x7e is unique? Does this
    > driver even support slave operation?
    >

    It's in fact 0x7F << 1. The same value is used in the 2.4 driver and
    in u-boot, as well. Slave operation is not supported.

    > Why is an 8xx driver matching all i2c cpm (i.e. what about cpm2)?
    >

    With the suggested change to use fsl,cpm-command, the driver should
    be able to use both cpm1 and cpm2. The operation and structs for i2c
    are identical. The only difference might be the hack^wsupport for
    relocation.

    Thanks,
    Jochen
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