[alsa-devel] [PATCH 2/6] ASoC: Davinci: McBSP: add device tree support for McBSP
Peter Ujfalusi
peter.ujfalusi at ti.com
Thu Apr 7 14:42:38 CEST 2016
On 04/06/16 16:21, Petr Kulhavy wrote:
> This adds DT support for the TI DA8xx/OMAP-L1x/AM17xx/AM18xx McBSP driver.
>
> Signed-off-by: Petr Kulhavy <petr at barix.com>
> ---
> sound/soc/davinci/Kconfig | 6 ++-
> sound/soc/davinci/davinci-i2s.c | 106 ++++++++++++++++++++++++++++++++++------
> 2 files changed, 96 insertions(+), 16 deletions(-)
>
> diff --git a/sound/soc/davinci/Kconfig b/sound/soc/davinci/Kconfig
> index 50ca291cc225..6b732d8e5896 100644
> --- a/sound/soc/davinci/Kconfig
> +++ b/sound/soc/davinci/Kconfig
> @@ -16,7 +16,11 @@ config SND_EDMA_SOC
> - DRA7xx family
>
> config SND_DAVINCI_SOC_I2S
> - tristate
> + tristate "DaVinci Multichannel Buffered Serial Port (McBSP) support"
> + depends on SND_EDMA_SOC
> + help
> + Say Y or M here if you want to have support for McBSP IP found in
> + Texas Instruments DaVinci DA850 SoCs.
>
> config SND_DAVINCI_SOC_MCASP
> tristate "Multichannel Audio Serial Port (McASP) support"
> diff --git a/sound/soc/davinci/davinci-i2s.c b/sound/soc/davinci/davinci-i2s.c
> index ec98548a5fc9..2ebfe86dd584 100644
> --- a/sound/soc/davinci/davinci-i2s.c
> +++ b/sound/soc/davinci/davinci-i2s.c
> @@ -4,9 +4,15 @@
> * Author: Vladimir Barinov, <vbarinov at embeddedalley.com>
> * Copyright: (C) 2007 MontaVista Software, Inc., <source at mvista.com>
> *
> + * DT support (c) 2016 Petr Kulhavy, Barix AG <petr at barix.com>
> + * based on davinci-mcasp.c DT support
> + *
> * This program is free software; you can redistribute it and/or modify
> * it under the terms of the GNU General Public License version 2 as
> * published by the Free Software Foundation.
> + *
> + * TODO:
> + * on DA850 implement HW FIFOs instead of DMA into DXR and DRR registers
The BFIFO looks identical to AFIFO for McASP...
> */
>
> #include <linux/init.h>
> @@ -648,15 +654,82 @@ static const struct snd_soc_component_driver davinci_i2s_component = {
> .name = "davinci-i2s",
> };
>
> +static struct snd_platform_data*
> +davinci_i2s_set_pdata_from_of(struct platform_device *pdev)
> +{
> + struct snd_platform_data *pdata = NULL;
> + struct device_node *np;
> + struct of_phandle_args dma_spec;
> + int ret;
> +
> + if (!IS_ENABLED(CONFIG_OF) || !pdev->dev.of_node)
> + return dev_get_platdata(&pdev->dev);
> +
> + pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
> + if (!pdata)
> + return ERR_PTR(-ENOMEM);
> +
> + np = pdev->dev.of_node;
> +
> + ret = of_property_match_string(np, "dma-names", "tx");
> + if (ret >= 0) {
> + ret = of_parse_phandle_with_args(np, "dmas", "#dma-cells", ret,
> + &dma_spec);
> + if (ret >= 0)
> + pdata->tx_dma_channel = dma_spec.args[0];
> + }
> +
> + ret = of_property_match_string(np, "dma-names", "rx");
> + if (ret >= 0) {
> + ret = of_parse_phandle_with_args(np, "dmas", "#dma-cells", ret,
> + &dma_spec);
> + if (ret >= 0)
> + pdata->rx_dma_channel = dma_spec.args[0];
> + }
Why would you do this? If we booted with DT the only thing needed by the
edma-pcm (dmaengine) is the name of the DMA channel...
> +
> + /* optional parameters */
> +
> + pdata->enable_channel_combine =
> + of_property_read_bool(np, "channel-combine");
This can only be done when the McBSP is used in DSP_x mode since this will
make the McBSP to transmit the stereo audio as mono on the bus.
After a quick look at the relevant parts in the driver, I think most of the
things are pretty much broken or at least they are not totally correct. McBSP
do support real I2S (SRGR:FWID), and the phase setup is wrong in the code. IMO.
I don't have HW to test the daVinci-MCBSP or the ASP so I can not comment on
how well things are working.
> +
> + /*
> + * pdata->clk_input_pin is deliberately not exported to DT
> + * and the default value of the clk_input_pin is MCBSP_CLKR.
> + * The value MCBSP_CLKS makes no sense as it turns the CPU
> + * to a bit clock master in the SND_SOC_DAIFMT_CBM_CFS mode
> + * where it should be bit clock slave!
> + */
Interesting. As a whole the clock selection part is mostly broken in the driver...
It would be better to add davinci_i2s_set_sysclk() to deal with the system
clock configuration.
> +
> + return pdata;
> +}
> +
> static int davinci_i2s_probe(struct platform_device *pdev)
> {
> + struct snd_platform_data *pdata;
> struct davinci_mcbsp_dev *dev;
> struct resource *mem, *res;
> void __iomem *io_base;
> int *dma;
> int ret;
>
> - mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + pdata = davinci_i2s_set_pdata_from_of(pdev);
> + if (IS_ERR(pdata)) {
> + dev_err(&pdev->dev, "Error populating platform data, err %ld\n",
> + PTR_ERR(pdata));
> + return PTR_ERR(pdata);
> + }
> +
> + mem = platform_get_resource_byname(pdev, IORESOURCE_MEM, "mpu");
> + if (!mem) {
> + dev_warn(&pdev->dev,
> + "\"mpu\" mem resource not found, using index 0\n");
> + mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!mem) {
> + dev_err(&pdev->dev, "no mem resource?\n");
> + return -ENODEV;
> + }
> + }
> +
> io_base = devm_ioremap_resource(&pdev->dev, mem);
> if (IS_ERR(io_base))
> return PTR_ERR(io_base);
> @@ -680,25 +753,21 @@ static int davinci_i2s_probe(struct platform_device *pdev)
> (dma_addr_t)(mem->start + DAVINCI_MCBSP_DRR_REG);
>
> /* first TX, then RX */
> - res = platform_get_resource(pdev, IORESOURCE_DMA, 0);
> - if (!res) {
> - dev_err(&pdev->dev, "no DMA resource\n");
> - ret = -ENXIO;
> - goto err_release_clk;
> - }
> dma = &dev->dma_request[SNDRV_PCM_STREAM_PLAYBACK];
> - *dma = res->start;
> dev->dma_data[SNDRV_PCM_STREAM_PLAYBACK].filter_data = dma;
> + res = platform_get_resource(pdev, IORESOURCE_DMA, 0);
> + if (res)
> + *dma = res->start;
> + else
> + *dma = pdata->tx_dma_channel;
Please follow the way davinci-mcasp does it right now:
dma_data = &mcasp->dma_data[SNDRV_PCM_STREAM_PLAYBACK];
...
dma = &mcasp->dma_request[SNDRV_PCM_STREAM_PLAYBACK];
res = platform_get_resource(pdev, IORESOURCE_DMA, 0);
if (res)
*dma = res->start;
else
*dma = pdata->tx_dma_channel;
/* dmaengine filter data for DT and non-DT boot */
if (pdev->dev.of_node)
dma_data->filter_data = "tx";
else
dma_data->filter_data = dma;
while we are here, I think the tx/rx_dma_channel is something we should just
get rid of. It is not used as far as I can tell.
Something like this would do I think:
dma_data = &mcasp->dma_data[SNDRV_PCM_STREAM_PLAYBACK];
...
res = platform_get_resource(pdev, IORESOURCE_DMA, 0);
if (res) {
dma = &mcasp->dma_request[SNDRV_PCM_STREAM_PLAYBACK];
*dma = res->start;
dma_data->filter_data = dma;
} else if (pdev->dev.of_node) {
dma_data->filter_data = "tx";
} else {
dev_err(&pdev->dev, "Missing DMA tx resource\n");
return -ENODEV;
}
>
> - res = platform_get_resource(pdev, IORESOURCE_DMA, 1);
> - if (!res) {
> - dev_err(&pdev->dev, "no DMA resource\n");
> - ret = -ENXIO;
> - goto err_release_clk;
> - }
> dma = &dev->dma_request[SNDRV_PCM_STREAM_CAPTURE];
> - *dma = res->start;
> dev->dma_data[SNDRV_PCM_STREAM_CAPTURE].filter_data = dma;
> + res = platform_get_resource(pdev, IORESOURCE_DMA, 1);
> + if (res)
> + *dma = res->start;
> + else
> + *dma = pdata->rx_dma_channel;
same comment as for the TX dma part.
>
> dev->dev = &pdev->dev;
> dev_set_drvdata(&pdev->dev, dev);
> @@ -737,11 +806,18 @@ static int davinci_i2s_remove(struct platform_device *pdev)
> return 0;
> }
>
> +static const struct of_device_id davinci_mcbsp_match[] = {
> + { .compatible = "ti,da850-mcbsp-audio" },
I would drop the "-audio" for the binding...
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, davinci_mcbsp_match);
> +
> static struct platform_driver davinci_mcbsp_driver = {
> .probe = davinci_i2s_probe,
> .remove = davinci_i2s_remove,
> .driver = {
> .name = "davinci-mcbsp",
> + .of_match_table = of_match_ptr(davinci_mcbsp_match),
The driver calls itself davinci-i2s.c and the prefixes internally used are
davinci_i2s_*.
The driver name is "davinci-mcbsp".
And it is basically a driver for daVinci ASP (the McBSP additions are not
configured at all).
I still think we should keep the davinci_i2s_* when adding new code, or rename
the whole driver and it's prefixes to something more sensible?
> },
> };
>
>
--
Péter
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