Re: [PATCH v2] ASoC: da7219: read fmw property to get mclk for non-dts systems

From: Agrawal, Akshu
Date: Tue May 01 2018 - 10:41:28 EST




On 5/1/2018 12:35 AM, Adam Thomson wrote:
On 30 April 2018 10:23, Akshu Agrawal wrote:

Non-dts based systems can use ACPI DSDT to pass on the mclk
to da7219.
This enables da7219 mclk to be linked to system clock.
Enable/Disable of the mclk is already handled in the codec so
platform drivers don't have to explicitly do handling of mclk.

There is already a means via DT to specify the MCLK for a device using the
generic clock DT bindings, and this driver already uses that. Should ACPI not
have something similar to that which is generic, rather than adding device
specific bindings/properties to achieve the same? There will be other drivers
that will want to do the same.


IMO for all non-dts based ACPI systems, DSDT would be the best and simplest way to link system clock to mclk. Currently, machine audio drivers handles the clock and this can be avoided by having this property.


Signed-off-by: Akshu Agrawal <akshu.agrawal@xxxxxxx>
---
v2: Fixed kbuild error
include/sound/da7219.h | 2 ++
sound/soc/codecs/da7219.c | 7 ++++++-
2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/include/sound/da7219.h b/include/sound/da7219.h
index 1bfcb16..df7ddf4 100644
--- a/include/sound/da7219.h
+++ b/include/sound/da7219.h
@@ -38,6 +38,8 @@ struct da7219_pdata {

const char *dai_clks_name;

+ const char *mclk_name;
+
/* Mic */
enum da7219_micbias_voltage micbias_lvl;
enum da7219_mic_amp_in_sel mic_amp_in_sel;
diff --git a/sound/soc/codecs/da7219.c b/sound/soc/codecs/da7219.c
index 980a6a8..aed68a4 100644
--- a/sound/soc/codecs/da7219.c
+++ b/sound/soc/codecs/da7219.c
@@ -1624,6 +1624,8 @@ static struct da7219_pdata *da7219_fw_to_pdata(struct
snd_soc_component *compone
dev_warn(dev, "Using default clk name: %s\n",
pdata->dai_clks_name);

+ device_property_read_string(dev, "dlg,mclk-name", &pdata->mclk_name);
+
if (device_property_read_u32(dev, "dlg,micbias-lvl", &of_val32) >= 0)
pdata->micbias_lvl = da7219_fw_micbias_lvl(dev, of_val32);
else
@@ -1905,7 +1907,10 @@ static int da7219_probe(struct snd_soc_component
*component)
da7219_handle_pdata(component);

/* Check if MCLK provided */
- da7219->mclk = devm_clk_get(component->dev, "mclk");
+ if (da7219->pdata->mclk_name)
+ da7219->mclk = clk_get(NULL, da7219->pdata->mclk_name);

By doing this you would need an associated 'clk_put()' whereas the devm call
avoids this.


Agreed, would add a corresponding clk_put call.

Thanks,
Akshu

+ if (!da7219->mclk)
+ da7219->mclk = devm_clk_get(component->dev, "mclk");
if (IS_ERR(da7219->mclk)) {
if (PTR_ERR(da7219->mclk) != -ENOENT) {
ret = PTR_ERR(da7219->mclk);
--
1.9.1