Re: Finding 'orphaned' i2c drivers

Jon Smirl
2009-02-23T15:16:01Z

On Mon, Feb 23, 2009 at 9:43 AM, Daniel Mack <daniel-rDUAYElUppE@public.gmane.org> wrote:
> Hi,
>
> On Mon, Feb 23, 2009 at 09:38:45AM -0500, Jon Smirl wrote:
>> On Mon, Feb 23, 2009 at 6:00 AM, Daniel Mack <daniel-rDUAYElUppE@public.gmane.org> wrote:
>> > what's the suggested way of implementing an i2c drver which does not
>> > have any other interfaces to the outside world than just the i2c device
>> > it is communicating with? More specifically, I implemented a driver for a
>> > Maxim clock generator and would like to use a proprietary interface with
>> > it from a alsa-soc module. I just can't find a sane way to access the
>> > driver's instance from there. It does exist somewhere in the linux
>> > device tree, but is there a simple function that iterates over it and
>> > returns it to me by name? Reading include/linux/device.h didn't point me
>> > to anything that could fit.
>>
>> The max9485? Which codec are you using it with? I tried submitting the
>> attached driver for the chip but Jean said it was too simple of a
>> driver.
>
> Yes, it's the same one.
>
>> I use it like this:
>>
>> static int dspeak01_fabric_hw_params(struct snd_pcm_substream
>> *substream, struct snd_pcm_hw_params *params)
>> {
>> uint rate, select;
>> int ret;
>> struct snd_soc_pcm_runtime *rtd = substream->private_data;
>> struct snd_soc_dai *cpu_dai = rtd->dai->cpu_dai;
>>
>> printk("dspeak01_fabric_hw_params\n");
>>
>> switch (params_rate(params)) {
>> case 11025:
>> case 22050:
>> case 44100:
>> case 88200:
>> case 176400:
>> rate = 22579200;
>> select = MAX9485_225792;
>> break;
>> default:
>> rate = 24576000;
>> select = MAX9485_245760;
>> break;
>> }
>> max9485_set(fabric.clock, select | MAX9485_CLK_OUT_2);
>
> I still don't see where you got the pointer from you are using here, and
> that's my whole question.

I'm on PowerPC, we have device tree.

i2c@3d00 {
#address-cells = <1>;
#size-cells = <0>;
compatible = "fsl,mpc5200b-i2c","fsl,mpc5200-i2c","fsl-i2c";
cell-index = <0>;
reg = <0x3d00 0x40>;
interrupts = <0x2 0xf 0x0>;
interrupt-parent = <&mpc5200_pic>;
fsl5200-clocking;

tas0:codec@1b {
compatible = "ti,tas5504";
reg = <0x1b>;
};
clock0:clock@68 {
compatible = "maxim,max9485";
reg = <0x68>;
};
};

fabric { /* audio fabric hardware */
compatible = "dspeak01-fabric";
clock-handle = <&clock0>;
};

>
> Your driver looks very much like the one I wrote, though ;)
>
> Daniel
>
>

--
Jon Smirl
jonsmirl-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org