Re: Finding 'orphaned' i2c drivers

Jon Smirl
2009-02-23T15:18:33Z

On Mon, Feb 23, 2009 at 10:16 AM, Jon Smirl <jonsmirl-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> 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>;
> };
>

In the fabric driver I use clock-handle and call
struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
{

To get the driver of the i2c device.

>
>>
>> Your driver looks very much like the one I wrote, though ;)
>>
>> Daniel
>>
>>
>
>
>
> --
> Jon Smirl
> jonsmirl-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
>

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