[alsa-devel] at91 SoC Modifications

[Paul Kavan]

On 6/25/07, Frank Mandarino <fmandarino at endrelia.com> wrote:
>
> Paul Kavan wrote:
> > Hello all:
> >
> > I have been struggling to determine why the sync line (TF0) behaves so
> > strangely when in capture mode yet acts fine in playback mode. So far,
> no
> > real clues. However, I do have a few questions. I have DATADEF set for
> TD0
> > set to 1. However, at the end of a playback it pulls to zero. Any clue
> why
> > this might be happening?
>
> Perhaps it is due to the SSC being reset when the playback channel is
> closed?


Yes, that is probably the cause. Thanks.

> Also, in the machine code, I set up some test code to printk back the gpio
> > registers:
> >
> > the code for the gpio is given as
> >
> > #define AT91_PIO_TK0    (1 << (AT91_PIN_PB16 - PIN_BASE) % 32)
> > #define AT91_PIO_TF0    (1 << (AT91_PIN_PB17 - PIN_BASE) % 32)
> > #define AT91_PIO_TD0    (1 << (AT91_PIN_PB18 - PIN_BASE) % 32)
> > #define AT91_PIO_RD0    (1 << (AT91_PIN_PB19 - PIN_BASE) % 32)
> > #define AT91_PIO_RK0    (1 << (AT91_PIN_PB20 - PIN_BASE) % 32)
> > #define AT91_PIO_RF0    (1 << (AT91_PIN_PB21 - PIN_BASE) % 32)
> > .
> > .
> > .
> >    ssc_pio_lines = AT91_PIO_TF0 | AT91_PIO_TK0 | AT91_PIO_TD0
> >            | AT91_PIO_RD0 /*| AT91_PIO_RK0 | AT91_PIO_RF0*/ ;
> >
> >        printk("SSC PIO LINES is 0x%x\n",ssc_pio_lines);
> >    /* Reset all PIO registers and assign lines to peripheral A */
> >     at91_sys_write(AT91_PIOB + PIO_PDR,  ssc_pio_lines);
> >     at91_sys_write(AT91_PIOB + PIO_ODR,  ssc_pio_lines);
> >     at91_sys_write(AT91_PIOB + PIO_IFDR, ssc_pio_lines);
> >     at91_sys_write(AT91_PIOB + PIO_CODR, ssc_pio_lines);
> >     at91_sys_write(AT91_PIOB + PIO_IDR,  ssc_pio_lines);
> >     at91_sys_write(AT91_PIOB + PIO_MDDR, ssc_pio_lines);
> >     at91_sys_write(AT91_PIOB + PIO_PUDR, ssc_pio_lines);
> >     at91_sys_write(AT91_PIOB + PIO_ASR,  ssc_pio_lines);
> >     at91_sys_write(AT91_PIOB + PIO_OWDR, ssc_pio_lines);
> >
> >        /*TEST CODE*/
> >        printk("PIOB-PDR is set to %d\n",at91_sys_read(AT91_PIOB +
> > PIO_PDR));
> >     printk("PIOB-ODR is set to %d\n",at91_sys_read(AT91_PIOB +
> PIO_ODR));
> >     printk("PIOB-IFDR is set to %d\n",at91_sys_read(AT91_PIOB +
> PIO_IFDR));
> >     printk("PIOB-CODR is set to %d\n",at91_sys_read(AT91_PIOB +
> PIO_CODR));
> >     printk("PIOB-IRD is set to %d\n",at91_sys_read(AT91_PIOB +
> PIO_IDR));
> >     printk("PIOB-MDDR is set to %d\n",at91_sys_read(AT91_PIOB +
> PIO_MDDR));
> >     printk("PIOB-PUDR is set to %d\n",at91_sys_read(AT91_PIOB +
> PIO_PUDR));
> >     printk("PIOB-ASR is set to %d\n",at91_sys_read(AT91_PIOB +
> PIO_ASR));
> >     printk("PIOB-OWDR is set to %d\n",at91_sys_read(AT91_PIOB +
> PIO_OWDR));
> >        /*END OF TEST CODE*/
> >
> >
> > and the result at boot is:
> >
> > AT91SAM9260EK W6811 Driver <1>
> > w6811: W6811 PCM SoC Audio 0.1
> > asoc: W6811 <-> at91-ssc0 mapping ok
> > SSC PIO LINES is 0xf0000
> > PIOB-PDR is set to 0
> > PIOB-ODR is set to 0
> > PIOB-IFDR is set to 0
> > PIOB-CODR is set to 0
> > PIOB-IRD is set to 0
> > PIOB-MDDR is set to 0
> > PIOB-PUDR is set to 0
> > PIOB-ASR is set to 0
> > PIOB-OWDR is set to 0
> >
> > ...why are all the registers set to 0?
>
> These registers are all write-only registers.  You have to read their
> corresponding status registers to see what values are set.


Is my face red? Missed that.....

../fam
> --
> Frank Mandarino                                fmandarino(a)endrelia.com
> Endrelia Technologies Inc.
> Toronto, Ontario, Canada
>



-- 
***************************************
Paul David Kavan
Project Engineer
GRH Electronics, Inc.
402-734-4900
pkavan at gmail.com
***************************************