Re: [PATCH 1/3] ASoC: mediatek: mt8188-mt6359: support dynamic pinctrl

From: AngeloGioacchino Del Regno
Date: Wed Jul 26 2023 - 07:54:42 EST


Il 26/07/23 13:36, Trevor Wu (吳文良) ha scritto:
On Wed, 2023-07-26 at 08:43 +0200, AngeloGioacchino Del Regno wrote:
Il 26/07/23 04:19, Trevor Wu (吳文良) ha scritto:
On Tue, 2023-07-25 at 09:06 +0200, AngeloGioacchino Del Regno
wrote:
Il 25/07/23 05:53, Trevor Wu ha scritto:
To avoid power leakage, it is recommended to replace the
default
pinctrl
state with dynamic pinctrl since certain audio pinmux functions
can
remain in a HIGH state even when audio is disabled. Linking
pinctrl
with
DAPM using SND_SOC_DAPM_PINCTRL will ensure that audio pins
remain
in
GPIO mode by default and only switch to an audio function when
necessary.

Signed-off-by: Trevor Wu <trevor.wu@xxxxxxxxxxxx>
---
sound/soc/mediatek/mt8188/mt8188-mt6359.c | 21
+++++++++++++++++++++
1 file changed, 21 insertions(+)

diff --git a/sound/soc/mediatek/mt8188/mt8188-mt6359.c
b/sound/soc/mediatek/mt8188/mt8188-mt6359.c
index 7c9e08e6a4f5..667d79f33bf2 100644
--- a/sound/soc/mediatek/mt8188/mt8188-mt6359.c
+++ b/sound/soc/mediatek/mt8188/mt8188-mt6359.c
@@ -246,6 +246,11 @@ static const struct snd_soc_dapm_widget
mt8188_mt6359_widgets[] = {
SND_SOC_DAPM_MIC("Headset Mic", NULL),
SND_SOC_DAPM_SINK("HDMI"),
SND_SOC_DAPM_SINK("DP"),
+
+ /* dynamic pinctrl */
+ SND_SOC_DAPM_PINCTRL("ETDM_SPK_PIN", "aud_etdm_spk_on",
"aud_etdm_spk_off"),
+ SND_SOC_DAPM_PINCTRL("ETDM_HP_PIN", "aud_etdm_hp_on",
"aud_etdm_hp_off"),
+ SND_SOC_DAPM_PINCTRL("MTKAIF_PIN", "aud_mtkaif_on",
"aud_mtkaif_off"),
};
static const struct snd_kcontrol_new
mt8188_mt6359_controls[] = {
@@ -267,6 +272,7 @@ static int
mt8188_mt6359_mtkaif_calibration(struct snd_soc_pcm_runtime
*rtd)
snd_soc_rtdcom_lookup(rtd, AFE_PCM_NAME);
struct snd_soc_component *cmpnt_codec =
asoc_rtd_to_codec(rtd, 0)->component;
+ struct snd_soc_dapm_widget *pin_w = NULL, *w;
struct mtk_base_afe *afe;
struct mt8188_afe_private *afe_priv;
struct mtkaif_param *param;
@@ -306,6 +312,18 @@ static int
mt8188_mt6359_mtkaif_calibration(struct snd_soc_pcm_runtime
*rtd)
return 0;
}
+ for_each_card_widgets(rtd->card, w) {
+ if (!strcmp(w->name, "MTKAIF_PIN")) {

if (strncmp(w->name, "MTKAIF_PIN", strlen(w->name) == 0) {
pin_w = w;
break;
}

That's safer.


If w->name is MTKAIF, the strncmp expression will return 0.
However,
the result is not expected. I prefer to keep strcmp here.


You could also do, instead

if (strncmp(w->name, "MTKAIF_PIN", strlen("MTKAIF_PIN") == 0))

...solving your concern.



From my understanding, strncmp is utilized to determine a string begins
with a particular prefix while strcmp is used to compare a whole
string. In this scenario, I wish to verify if the widget name is
exactly 'MTKAIF_PIN', so I believe using strcmp would be more
appropriate.

Using either strlen(w->name) or strlen("MTKAIF_PIN") may lead to
incorrect results when w->name is either MTKAIF or MTKAIF_PIN1.

Thanks,
Trevor

strcmp() and strncmp() are the same; except strncmp() compares *at most* `n` bytes,
where `n` is my `strlen("MTKAIF_PIN")`.

From Linux man pages....
https://www.man7.org/linux/man-pages/man3/strcmp.3.html

Regards,
Angelo