[alsa-devel] ASOC: Best way to get private data from machine driver to the other drivers?
I'm writing an ASOC driver. When my machine driver loads, it determines some hardware information for the DMA controllers, some other hardware information for the I2S controller, and even more information for the codec. I want to be able to pass all this information to each of the three other drivers. Unfortunately, it doesn't appear that I have enough "private_data" pointers available to me. The current ASOC drivers all use statically defined global structures and indexes into arrays of these structures to identify individual devices, such associating I2S controller #2 with DMA channels 3 and 4. On PowerPC, this doesn't work. The actual hardware configuration is determined at runtime (see arch/powerpc/boot/dts/), and so the machine driver needs to collect all the information and make all the device-to-device associations. For example, the PCM driver has an open function: static struct snd_pcm_ops fsl_dma_ops = { .open = fsl_dma_open, ... static int fsl_dma_open(struct snd_pcm_substream *substream) { ... What I would like is for fsl_dma_open() to be able to obtain pointers to the DMA controller's registers (there are two controllers with 4 channels each) by looking inside 'substream'. How can I do that? -- Timur Tabi Linux Kernel Developer @ Freescale
On Fri, 2007-09-28 at 16:14 -0500, Timur Tabi wrote:
I'm writing an ASOC driver. When my machine driver loads, it determines some hardware information for the DMA controllers, some other hardware information for the I2S controller, and even more information for the codec.
I want to be able to pass all this information to each of the three other drivers. Unfortunately, it doesn't appear that I have enough "private_data" pointers available to me.
The current ASOC drivers all use statically defined global structures and indexes into arrays of these structures to identify individual devices, such associating I2S controller #2 with DMA channels 3 and 4. On PowerPC, this doesn't work. The actual hardware configuration is determined at runtime (see arch/powerpc/boot/dts/), and so the machine driver needs to collect all the information and make all the device-to-device associations.
For example, the PCM driver has an open function:
static struct snd_pcm_ops fsl_dma_ops = { .open = fsl_dma_open, ...
static int fsl_dma_open(struct snd_pcm_substream *substream) { ...
What I would like is for fsl_dma_open() to be able to obtain pointers to the DMA controller's registers (there are two controllers with 4 channels each) by looking inside 'substream'. How can I do that?
I think we have addressed this now in ASoC V2. Every component driver now registers as a standard Linux device driver. It would probably be possible to read the dts configuration at probe() and then configure the driver with the correct DMA pointers before calling driver_register(). http://opensource.wolfsonmicro.com/cgi-bin/gitweb/gitweb.cgi?p=linux-2.6-aso... Could you have a look at the V2 i.mx31 SSI driver and let me know if we need further changes for better dts support. Thanks Liam
Liam Girdwood wrote:
Could you have a look at the V2 i.mx31 SSI driver and let me know if we need further changes for better dts support.
I'll do that. However, I still have the same problem - without a git-http interface, my ability to "work with" that repository is limited. Can you create a repo on kernel.org? I have git better access to that site. -- Timur Tabi Linux Kernel Developer @ Freescale
On Mon, 2007-10-01 at 15:10 -0500, Timur Tabi wrote:
Liam Girdwood wrote:
Could you have a look at the V2 i.mx31 SSI driver and let me know if we need further changes for better dts support.
I'll do that. However, I still have the same problem - without a git-http interface, my ability to "work with" that repository is limited. Can you create a repo on kernel.org? I have git better access to that site.
Do you know who would be the best person to ask for this ? If it's ok with the kernel.org folks I can do this. Liam
Liam Girdwood wrote:
Do you know who would be the best person to ask for this ?
If it's ok with the kernel.org folks I can do this.
http://kernel.org/faq/#account -- Timur Tabi Linux Kernel Developer @ Freescale
Liam Girdwood wrote:
On Mon, 2007-10-01 at 15:10 -0500, Timur Tabi wrote:
Liam Girdwood wrote:
Could you have a look at the V2 i.mx31 SSI driver and let me know if we need further changes for better dts support. I'll do that. However, I still have the same problem - without a git-http interface, my ability to "work with" that repository is limited. Can you create a repo on kernel.org? I have git better access to that site.
Do you know who would be the best person to ask for this ?
I take it that enabling git-http access is not an option? Normally, that would be easier than getting an account on kernel.org. -- Timur Tabi Linux Kernel Developer @ Freescale
Liam Girdwood wrote:
Could you have a look at the V2 i.mx31 SSI driver and let me know if we need further changes for better dts support.
I'm trying to port the CS4270 codec driver (it's easier) to ASOC v2, and I see that you don't have snd_pcm_rate_to_rate_bit(). Where did it go? -- Timur Tabi Linux Kernel Developer @ Freescale
On Mon, 2007-10-01 at 16:49 -0500, Timur Tabi wrote:
Liam Girdwood wrote:
Could you have a look at the V2 i.mx31 SSI driver and let me know if we need further changes for better dts support.
I'm trying to port the CS4270 codec driver (it's easier) to ASOC v2, and I see that you don't have snd_pcm_rate_to_rate_bit(). Where did it go?
We never had a snd_pcm_rate_to_rate_bit() in the ASoC code, perhaps you mean something else ? Liam
Liam Girdwood wrote:
On Mon, 2007-10-01 at 16:49 -0500, Timur Tabi wrote:
Liam Girdwood wrote:
Could you have a look at the V2 i.mx31 SSI driver and let me know if we need further changes for better dts support. I'm trying to port the CS4270 codec driver (it's easier) to ASOC v2, and I see that you don't have snd_pcm_rate_to_rate_bit(). Where did it go?
We never had a snd_pcm_rate_to_rate_bit() in the ASoC code, perhaps you mean something else ?
In may not be part of ASoC, but it's part of ALSA, and I need it. It's not just in your repository. sound/core/pcm_misc.c /** * snd_pcm_rate_to_rate_bit - converts sample rate to SNDRV_PCM_RATE_xxx bit * @rate: the sample rate to convert * * Returns the SNDRV_PCM_RATE_xxx flag that corresponds to the given rate, or * SNDRV_PCM_RATE_KNOT for an unknown rate. */ unsigned int snd_pcm_rate_to_rate_bit(unsigned int rate) { unsigned int i; for (i = 0; i < snd_pcm_known_rates.count; i++) if (snd_pcm_known_rates.list[i] == rate) return 1u << i; return SNDRV_PCM_RATE_KNOT; } EXPORT_SYMBOL(snd_pcm_rate_to_rate_bit); -- Timur Tabi Linux Kernel Developer @ Freescale
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Timur Tabi