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

From: Pierre-Louis Bossart
Date: Tue May 01 2018 - 12:00:07 EST


On 5/1/18 9:31 AM, Agrawal, Akshu wrote:


On 4/30/2018 9:54 PM, Pierre-Louis Bossart wrote:
On 4/30/18 4:23 AM, 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.

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 {
ÂÂÂÂÂ const char *dai_clks_name;
+ÂÂÂ const char *mclk_name;
+
ÂÂÂÂÂ /* Mic */
ÂÂÂÂÂ enum da7219_micbias_voltage micbias_lvl;
ÂÂÂÂÂ 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
ÂÂÂÂÂÂÂÂÂ dev_warn(dev, "Using default clk name: %s\n",
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂ pdata->dai_clks_name);
+ÂÂÂ device_property_read_string(dev, "dlg,mclk-name", &pdata->mclk_name);
+
ÂÂÂÂÂ if (device_property_read_u32(dev, "dlg,micbias-lvl", &of_val32) >= 0)
ÂÂÂÂÂÂÂÂÂ pdata->micbias_lvl = da7219_fw_micbias_lvl(dev, of_val32);
ÂÂÂÂÂ else
@@ -1905,7 +1907,10 @@ static int da7219_probe(struct snd_soc_component *component)
ÂÂÂÂÂ da7219_handle_pdata(component);
ÂÂÂÂÂ /* Check if MCLK provided */
-ÂÂÂ da7219->mclk = devm_clk_get(component->dev, "mclk");
+ÂÂÂ if (da7219->pdata->mclk_name)
+ÂÂÂÂÂÂÂ da7219->mclk = clk_get(NULL, da7219->pdata->mclk_name);
+ÂÂÂ if (!da7219->mclk)
+ÂÂÂÂÂÂÂ da7219->mclk = devm_clk_get(component->dev, "mclk");

this looks weird, why are you using different clk functions depending on the existence of a _DSD property? Why not just change the name and keep the same flow, e.g something like

if(!da7219->pdata->mclk_name)
ÂÂÂÂÂda7219->pdata->mclk_name = "mclk";
da7219->mclk = devm_clk_get(component->dev, da7219->pdata->mclk_name);



We can't use devm_clk_get as the value of dev argument has to be NULL, which can not be used with devm_clk_get.
System clock which are linked to mclk are registered by a separate ACPI device. And this exposing of DSD property is for all those platforms which are non-dts based.

Alternatively you could modify clk_get to use device_property instead of of_property.


ÂÂÂÂÂ if (IS_ERR(da7219->mclk)) {
ÂÂÂÂÂÂÂÂÂ if (PTR_ERR(da7219->mclk) != -ENOENT) {
ÂÂÂÂÂÂÂÂÂÂÂÂÂ ret = PTR_ERR(da7219->mclk);