On Tue, May 01, 2012 at 09:44:48PM +0800, Shawn Guo wrote:
> On Fri, Apr 27, 2012 at 03:02:57PM +0800, Richard Zhao wrote:
> > From: Richard Zhao <[email protected]>
> > 
> > It tries to clk_get the clock. And if it failed, it assumes the clock
> > by default enabled.
> > 
> > Signed-off-by: Richard Zhao <[email protected]>
> > ---
> >  sound/soc/fsl/imx-sgtl5000.c |   40 
> > ++++++++++++++++++++++++++++++++--------
> >  1 files changed, 32 insertions(+), 8 deletions(-)
> > 
> > diff --git a/sound/soc/fsl/imx-sgtl5000.c b/sound/soc/fsl/imx-sgtl5000.c
> > index 73b935e..3a729ca 100644
> > --- a/sound/soc/fsl/imx-sgtl5000.c
> > +++ b/sound/soc/fsl/imx-sgtl5000.c
> > @@ -13,6 +13,8 @@
> >  #include <linux/module.h>
> >  #include <linux/of.h>
> >  #include <linux/of_platform.h>
> > +#include <linux/of_i2c.h>
> > +#include <linux/clk.h>
> >  #include <sound/soc.h>
> >  
> >  #include "../codecs/sgtl5000.h"
> > @@ -25,6 +27,7 @@ struct imx_sgtl5000_data {
> >     struct snd_soc_card card;
> >     char codec_dai_name[DAI_NAME_SIZE];
> >     char platform_name[DAI_NAME_SIZE];
> > +   struct clk *codec_clk;
> >     unsigned int clk_frequency;
> >  };
> >  
> > @@ -58,6 +61,7 @@ static int __devinit imx_sgtl5000_probe(struct 
> > platform_device *pdev)
> >     struct device_node *np = pdev->dev.of_node;
> >     struct device_node *ssi_np, *codec_np;
> >     struct platform_device *ssi_pdev;
> > +   struct i2c_client *codec_dev;
> >     struct imx_sgtl5000_data *data;
> >     int int_port, ext_port;
> >     int ret;
> > @@ -113,6 +117,11 @@ static int __devinit imx_sgtl5000_probe(struct 
> > platform_device *pdev)
> >             ret = -EINVAL;
> >             goto fail;
> >     }
> > +   codec_dev = of_find_i2c_device_by_node(codec_np);
> > +   if (!codec_dev) {
> > +           dev_err(&pdev->dev, "failed to find codec platform device\n");
> > +           return -EINVAL;
> > +   }
> 
> What if the codec is accessed via SPI bus on some machines?
> 
> >  
> >     data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
> >     if (!data) {
> > @@ -120,11 +129,20 @@ static int __devinit imx_sgtl5000_probe(struct 
> > platform_device *pdev)
> >             goto fail;
> >     }
> >  
> > -   ret = of_property_read_u32(codec_np, "clock-frequency",
> > -                              &data->clk_frequency);
> > -   if (ret) {
> > -           dev_err(&pdev->dev, "clock-frequency missing or invalid\n");
> > -           goto fail;
> > +   data->codec_clk = clk_get(&codec_dev->dev, NULL);
> 
> It's a clock of sgtl5000 codec.  I feel it makes more sense to have
> sgtl5000 device driver than machine driver to manage this clock.
The ASoC machine driver handled the clock settings, I just followed the
same way, using snd_soc_dai_set_sysclk to set codec clk. But what you
said  is reasonable. I also find it's impossible to use devm_get_clk.

Mark, do you suggest get clk in ASoC machine driver or in codec driver?

Thanks
Richard
> 
> Regards,
> Shawn
> 
> > +   if (IS_ERR(data->codec_clk)) {
> > +           /* assuming clock enabled by default */
> > +           data->codec_clk = NULL;
> > +           ret = of_property_read_u32(codec_np, "clock-frequency",
> > +                                   &data->clk_frequency);
> > +           if (ret) {
> > +                   dev_err(&codec_dev->dev,
> > +                           "clock-frequency missing or invalid\n");
> > +                   goto fail;
> > +           }
> > +   } else {
> > +           data->clk_frequency = clk_get_rate(data->codec_clk);
> > +           clk_prepare_enable(data->codec_clk);
> >     }
> 

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