Re: [PATCH v4 13/17] ASoC: fsl_ssi: Setup AC97 in fsl_ssi_hw_init()

[Maciej S. Szmigiero]

On 16.01.2018 00:16, Nicolin Chen wrote:
> AC97 configures most of registers earlier to start a communication
> with CODECs in order to successfully initialize CODEC. Currently,
> _fsl_ssi_set_dai_fmt() and fsl_ssi_setup_ac97() are called to get
> all SSI registers properly set.
> 
> Since now the driver has a fsl_ssi_hw_init() to handle all register
> initial settings, this patch moves those register settings of AC97
> to the fsl_ssi_hw_init() as well.
> 
> Meanwhile it applies _fsl_ssi_set_dai_fmt() call to AC97 only since
> other formats would be configured via normal set_dai_fmt() directly.
> 
> This patch also adds fsl_ssi_hw_clean() to cleanup control bits for
> AC97 in the platform remote() function.
> 
> Signed-off-by: Nicolin Chen 
> Tested-by: Caleb Crome 
> ---
> Changelog
> v2
>  * Moved all to fsl_ssi_hw_init() in platform probe()
>  * Added fsl_ssi_hw_clean() instead of dai remove()
> 
>  sound/soc/fsl/fsl_ssi.c | 26 --
>  1 file changed, 20 insertions(+), 6 deletions(-)
> 
> diff --git a/sound/soc/fsl/fsl_ssi.c b/sound/soc/fsl/fsl_ssi.c
> index 50648f5..ebb3eb9 100644
> --- a/sound/soc/fsl/fsl_ssi.c
> +++ b/sound/soc/fsl/fsl_ssi.c
> @@ -1255,10 +1252,28 @@ static int fsl_ssi_hw_init(struct fsl_ssi *ssi)
>   regmap_update_bits(ssi->regs, REG_SSI_SCR,
>  SSI_SCR_TCH_EN, SSI_SCR_TCH_EN);
>  
> + /* AC97 should start earlier to communicate with CODECs */
> + if (fsl_ssi_is_ac97(ssi)) {
> + _fsl_ssi_set_dai_fmt(ssi->dev, ssi, ssi->dai_fmt);
> + fsl_ssi_setup_ac97(ssi);
> + }
> +
>   return 0;
>  }
>  
>  /**
> + * Clear SSI registers
> + */
> +static void fsl_ssi_hw_clean(struct fsl_ssi *ssi)
> +{
> + /* Disable registers for AC97 */
> + if (fsl_ssi_is_ac97(ssi)) {
> + regmap_write(ssi->regs, REG_SSI_SCR, 0);
> + regmap_write(ssi->regs, REG_SSI_SACNT, 0);
> + regmap_write(ssi->regs, REG_SSI_SOR, 0);

These writes cause a hard SoC lockup when unloading the driver.

The following replacement order seems to be tolerated by the SSI:
regmap_update_bits(ssi->regs, REG_SSI_SCR, SSI_SCR_TE | SSI_SCR_RE, 0);
regmap_write(ssi->regs, REG_SSI_SACNT, 0);
regmap_write(ssi->regs, REG_SSI_SOR, 0);
regmap_update_bits(ssi->regs, REG_SSI_SCR, SSI_SCR_SSIEN, 0);

BTW: I've also tried disabling SSIEN before writing to SACNT and SOR
(both together with (TR | RE) and also as a separate step) but this
still caused a lockup.

> @@ -1587,6 +1599,8 @@ static int fsl_ssi_remove(struct platform_device *pdev)
>  {
>   struct fsl_ssi *ssi = dev_get_drvdata(>dev);
>  
> + fsl_ssi_hw_clean(ssi);
> +

We need to move this call...

>   fsl_ssi_debugfs_remove(>dbg_stats);
>  
>   if (ssi->pdev)
>   platform_device_unregister(ssi->card_pdev);

...here, after the AC'97 CODEC platform device is unregistered, since the
CODEC shutdown may need a working AC'97 register communication.

Maciej

[PATCH v4 13/17] ASoC: fsl_ssi: Setup AC97 in fsl_ssi_hw_init()

[Nicolin Chen]

AC97 configures most of registers earlier to start a communication
with CODECs in order to successfully initialize CODEC. Currently,
_fsl_ssi_set_dai_fmt() and fsl_ssi_setup_ac97() are called to get
all SSI registers properly set.

Since now the driver has a fsl_ssi_hw_init() to handle all register
initial settings, this patch moves those register settings of AC97
to the fsl_ssi_hw_init() as well.

Meanwhile it applies _fsl_ssi_set_dai_fmt() call to AC97 only since
other formats would be configured via normal set_dai_fmt() directly.

This patch also adds fsl_ssi_hw_clean() to cleanup control bits for
AC97 in the platform remote() function.

Signed-off-by: Nicolin Chen 
Tested-by: Caleb Crome 
---
Changelog
v2
 * Moved all to fsl_ssi_hw_init() in platform probe()
 * Added fsl_ssi_hw_clean() instead of dai remove()

 sound/soc/fsl/fsl_ssi.c | 26 --
 1 file changed, 20 insertions(+), 6 deletions(-)

diff --git a/sound/soc/fsl/fsl_ssi.c b/sound/soc/fsl/fsl_ssi.c
index 50648f5..ebb3eb9 100644
--- a/sound/soc/fsl/fsl_ssi.c
+++ b/sound/soc/fsl/fsl_ssi.c
@@ -987,9 +987,6 @@ static int _fsl_ssi_set_dai_fmt(struct device *dev,
regmap_write(regs, REG_SSI_SRCR, srcr);
regmap_write(regs, REG_SSI_SCR, scr);
 
-   if ((fmt & SND_SOC_DAIFMT_FORMAT_MASK) == SND_SOC_DAIFMT_AC97)
-   fsl_ssi_setup_ac97(ssi);
-
return 0;
 }
 
@@ -1255,10 +1252,28 @@ static int fsl_ssi_hw_init(struct fsl_ssi *ssi)
regmap_update_bits(ssi->regs, REG_SSI_SCR,
   SSI_SCR_TCH_EN, SSI_SCR_TCH_EN);
 
+   /* AC97 should start earlier to communicate with CODECs */
+   if (fsl_ssi_is_ac97(ssi)) {
+   _fsl_ssi_set_dai_fmt(ssi->dev, ssi, ssi->dai_fmt);
+   fsl_ssi_setup_ac97(ssi);
+   }
+
return 0;
 }
 
 /**
+ * Clear SSI registers
+ */
+static void fsl_ssi_hw_clean(struct fsl_ssi *ssi)
+{
+   /* Disable registers for AC97 */
+   if (fsl_ssi_is_ac97(ssi)) {
+   regmap_write(ssi->regs, REG_SSI_SCR, 0);
+   regmap_write(ssi->regs, REG_SSI_SACNT, 0);
+   regmap_write(ssi->regs, REG_SSI_SOR, 0);
+   }
+}
+/**
  * Make every character in a string lower-case
  */
 static void make_lowercase(char *s)
@@ -1540,9 +1555,6 @@ static int fsl_ssi_probe(struct platform_device *pdev)
}
 
 done:
-   if (ssi->dai_fmt)
-   _fsl_ssi_set_dai_fmt(dev, ssi, ssi->dai_fmt);
-
/* Initially configures SSI registers */
fsl_ssi_hw_init(ssi);
 
@@ -1587,6 +1599,8 @@ static int fsl_ssi_remove(struct platform_device *pdev)
 {
struct fsl_ssi *ssi = dev_get_drvdata(>dev);
 
+   fsl_ssi_hw_clean(ssi);
+
fsl_ssi_debugfs_remove(>dbg_stats);
 
if (ssi->pdev)
-- 
2.7.4