* Re: [PATCH/RFC] [POWERPC] Add i2c pins to dts and board setup on 01-31-08
[not found] <87AC5F88F03E6249AEA68D40BD3E00BE1418A0B3@zcarhxm2.corp.nortel.com>
@ 2008-02-14 11:39 ` Jochen Friedrich
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From: Jochen Friedrich @ 2008-02-14 11:39 UTC (permalink / raw)
To: Nima Montaser; +Cc: linuxppc-dev list
Hi Nima,
> I've got a couple of comments about the above patch - I'm not quite sure
> how to add my comments to the ozlab.org site.
simply replying to the original mail will add your comments.
> 1 -
> -- a/arch/powerpc/boot/dts/mpc8272ads.dts
> [snip]
> + i2c@11860 {
> + compatible = "fsl,mpc8248-i2c",
> [NIMA] Are you sure it should be mpc8248, or do you want 8272. I know
> they are essentially the same chip, but just to avoid confusion, it
> maybe better as 8272.
Good catch, thanks! As i don't have a CPM2 chip myself, i had a tester with
a MPC8248. I just took his dts parts.
> 2-
> +++ b/arch/powerpc/platforms/82xx/mpc8272_ads.c
> @@ -96,6 +96,11 @@ static struct cpm_pin mpc8272_ads_pins[] = {
> {1, 31, CPM_PIN_OUTPUT | CPM_PIN_PRIMARY},
> {2, 16, CPM_PIN_INPUT | CPM_PIN_PRIMARY},
> {2, 17, CPM_PIN_INPUT | CPM_PIN_PRIMARY},
> +
> + /* I2C */
> + {3, 26, CPM_PIN_INPUT | CPM_PIN_SECONDARY | CPM_PIN_OPENDRAIN},
> + {3, 27, CPM_PIN_INPUT | CPM_PIN_SECONDARY | CPM_PIN_OPENDRAIN},
>
> [NIMA] The MPC8272 manual states that it should be pins 14/15 and not
> 26/27.
Ah thanks.
> However, in all my accesses,
> - 1st write is successful
> - 1st read fails (times out)
> - 2nd read succeeds
>
> Here is the debug log:
> i2c-adapter i2c-0: ioctl, cmd=0x703, arg=0x40
> i2c-dev: i2c-0 writing 2 bytes.
> i2c-adapter i2c-0: master_xfer[0] W, addr=0x40, len=2
> i2c-adapter i2c-0: i2c-algo-cpm.o: R: 0 T: 0
> i2c-adapter i2c-0: cpm_iic_write(abyte=0x80)
> i2c-adapter i2c-0: tx sc 0 bc00
> i2c-adapter i2c-0: test ready.
> i2c-adapter i2c-0: not ready.
> i2c-adapter i2c-0: Interrupt: 2
> i2c-adapter i2c-0: Interrupt: 1
> i2c-adapter i2c-0: test ready.
> i2c-adapter i2c-0: ready.
> i2c-adapter i2c-0: tx sc 0 3c00
> i2c-dev: i2c-0 reading 1 bytes.
> i2c-adapter i2c-0: master_xfer[0] R, addr=0x40, len=1
> i2c-adapter i2c-0: i2c-algo-cpm.o: R: 0 T: 0
> i2c-adapter i2c-0: cpm_i2c_read(abyte=0x81)
> i2c-adapter i2c-0: test ready.
> i2c-adapter i2c-0: not ready.
> i2c-adapter i2c-0: I2C read: timeout!
> i2c-adapter i2c-0: cpm_i2c_force_close()
> i2c-dev: i2c-0 reading 1 bytes.
> i2c-adapter i2c-0: master_xfer[0] R, addr=0x40, len=1
> i2c-adapter i2c-0: i2c-algo-cpm.o: R: 0 T: 0
> i2c-adapter i2c-0: cpm_i2c_read(abyte=0x81)
> i2c-adapter i2c-0: test ready.
> i2c-adapter i2c-0: not ready.
> i2c-adapter i2c-0: Interrupt: 1
> i2c-adapter i2c-0: test ready.
> i2c-adapter i2c-0: ready.
> i2c-adapter i2c-0: rx sc 2c00, rx sc 1800
>
> Any ideas?
What does you chip expect? Start-Write-Start-Read-Stop or Start-Write-Stop, Start-Read-Stop?
Did you try chaining the write and read request (put them into the same msg)?
Thanks,
Jochen
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