[v2] ASoC: wm8960: Let wm8960 codec driver manage its own MCLK
diff mbox

Message ID 1417681425-4360-1-git-send-email-b50113@freescale.com
State New, archived
Headers show

Commit Message

Zidan Wang Dec. 4, 2014, 8:23 a.m. UTC
When we want to use wm8960 codec, we should enable its MCLK in machine
driver. It's reasonable for wm8960 codec driver to manage its own MCLK to
save power.

If platform data is not supplied, we will get MCLK from device tree and check
the return code to handle probe deferral.

Enable runtime power management, and auto enable/disable MCLK in pm_runtime
resume and suspend. When wm8960 codec is being used, it will triger resume()
to enable MCLK. When codec is not being used, it will triger suspend() to
disable MCLK.

If we use PLL to generate sysclk, wm8960_set_dai_pll() will enable PLL. But
PLL doesn't power down after using codec. So power down PLL in suspend().

Signed-off-by: Zidan Wang <b50113@freescale.com>
---
 include/sound/wm8960.h    |  1 +
 sound/soc/codecs/wm8960.c | 59 ++++++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 57 insertions(+), 3 deletions(-)

Comments

Mark Brown Dec. 4, 2014, 11:25 a.m. UTC | #1
On Thu, Dec 04, 2014 at 04:23:45PM +0800, Zidan Wang wrote:

> If we use PLL to generate sysclk, wm8960_set_dai_pll() will enable PLL. But
> PLL doesn't power down after using codec. So power down PLL in suspend().

That would be a bug in the machine driver, the machine driver should be
disabling the PLL when it suspends since the startup and shutdown of the
PLL need to be coordinated with the input clocks.  Besides, if we were
doing this in the CODEC driver then as I said last time the PLL needs to
be restored on resume since the machine driver should be able to expect
that settings it has made are preserved (eg, if it sets things up on
init).
Zidan Wang Dec. 4, 2014, 12:34 p.m. UTC | #2
Thanks for your reply. 
You are right, the machine driver should disable the PLL.


Best Regards,
Zidan

-----Original Message-----
From: Mark Brown [mailto:broonie@kernel.org] 
Sent: Thursday, December 04, 2014 7:25 PM
To: Wang Zidan-B50113
Cc: lgirdwood@gmail.com; perex@perex.cz; tiwai@suse.de; lars@metafoo.de; ckeepax@opensource.wolfsonmicro.com; Xiubo Li-B47053; patches@opensource.wolfsonmicro.com; alsa-devel@alsa-project.org; linux-kernel@vger.kernel.org
Subject: Re: [alsa-devel][PATCH v2] ASoC: wm8960: Let wm8960 codec driver manage its own MCLK

On Thu, Dec 04, 2014 at 04:23:45PM +0800, Zidan Wang wrote:

> If we use PLL to generate sysclk, wm8960_set_dai_pll() will enable 
> PLL. But PLL doesn't power down after using codec. So power down PLL in suspend().

That would be a bug in the machine driver, the machine driver should be disabling the PLL when it suspends since the startup and shutdown of the PLL need to be coordinated with the input clocks.  Besides, if we were doing this in the CODEC driver then as I said last time the PLL needs to be restored on resume since the machine driver should be able to expect that settings it has made are preserved (eg, if it sets things up on init).

Patch
diff mbox

diff --git a/include/sound/wm8960.h b/include/sound/wm8960.h
index e8ce8ee..d7e84ed 100644
--- a/include/sound/wm8960.h
+++ b/include/sound/wm8960.h
@@ -16,6 +16,7 @@ 
 #define WM8960_DRES_MAX  3
 
 struct wm8960_data {
+	struct clk *mclk;
 	bool capless;  /* Headphone outputs configured in capless mode */
 
 	bool shared_lrclk;  /* DAC and ADC LRCLKs are wired together */
diff --git a/sound/soc/codecs/wm8960.c b/sound/soc/codecs/wm8960.c
index 031a1ae..2c7a97a 100644
--- a/sound/soc/codecs/wm8960.c
+++ b/sound/soc/codecs/wm8960.c
@@ -15,6 +15,8 @@ 
 #include <linux/init.h>
 #include <linux/delay.h>
 #include <linux/pm.h>
+#include <linux/clk.h>
+#include <linux/pm_runtime.h>
 #include <linux/i2c.h>
 #include <linux/slab.h>
 #include <sound/core.h>
@@ -978,7 +980,7 @@  static const struct regmap_config wm8960_regmap = {
 	.volatile_reg = wm8960_volatile,
 };
 
-static void wm8960_set_pdata_from_of(struct i2c_client *i2c,
+static int wm8960_set_pdata_from_of(struct i2c_client *i2c,
 				struct wm8960_data *pdata)
 {
 	const struct device_node *np = i2c->dev.of_node;
@@ -988,6 +990,15 @@  static void wm8960_set_pdata_from_of(struct i2c_client *i2c,
 
 	if (of_property_read_bool(np, "wlf,shared-lrclk"))
 		pdata->shared_lrclk = true;
+
+	pdata->mclk = devm_clk_get(&i2c->dev, NULL);
+
+	if (IS_ERR(pdata->mclk)) {
+		if (PTR_ERR(pdata->mclk) == -EPROBE_DEFER)
+			return -EPROBE_DEFER;
+	}
+
+	return 0;
 }
 
 static int wm8960_i2c_probe(struct i2c_client *i2c,
@@ -1008,8 +1019,11 @@  static int wm8960_i2c_probe(struct i2c_client *i2c,
 
 	if (pdata)
 		memcpy(&wm8960->pdata, pdata, sizeof(struct wm8960_data));
-	else if (i2c->dev.of_node)
-		wm8960_set_pdata_from_of(i2c, &wm8960->pdata);
+	else if (i2c->dev.of_node) {
+		ret = wm8960_set_pdata_from_of(i2c, &wm8960->pdata);
+		if (ret != 0)
+			return ret;
+	}
 
 	ret = wm8960_reset(wm8960->regmap);
 	if (ret != 0) {
@@ -1041,6 +1055,9 @@  static int wm8960_i2c_probe(struct i2c_client *i2c,
 
 	i2c_set_clientdata(i2c, wm8960);
 
+	pm_runtime_enable(&i2c->dev);
+	pm_request_idle(&i2c->dev);
+
 	ret = snd_soc_register_codec(&i2c->dev,
 			&soc_codec_dev_wm8960, &wm8960_dai, 1);
 
@@ -1053,6 +1070,41 @@  static int wm8960_i2c_remove(struct i2c_client *client)
 	return 0;
 }
 
+#ifdef CONFIG_PM_RUNTIME
+static int wm8960_runtime_resume(struct device *dev)
+{
+	struct wm8960_priv *wm8960 = dev_get_drvdata(dev);
+	int ret;
+
+	if (!IS_ERR(wm8960->pdata.mclk)) {
+		ret = clk_prepare_enable(wm8960->pdata.mclk);
+		if (ret) {
+			dev_err(dev, "Failed to enable MCLK: %d\n", ret);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int wm8960_runtime_suspend(struct device *dev)
+{
+	struct wm8960_priv *wm8960 = dev_get_drvdata(dev);
+
+	/* Power down PLL to save power */
+	regmap_update_bits(wm8960->regmap, WM8960_POWER2, 0x1, 0);
+
+	if (!IS_ERR(wm8960->pdata.mclk))
+		clk_disable_unprepare(wm8960->pdata.mclk);
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops wm8960_pm = {
+	SET_RUNTIME_PM_OPS(wm8960_runtime_suspend, wm8960_runtime_resume, NULL)
+};
+
 static const struct i2c_device_id wm8960_i2c_id[] = {
 	{ "wm8960", 0 },
 	{ }
@@ -1070,6 +1122,7 @@  static struct i2c_driver wm8960_i2c_driver = {
 		.name = "wm8960",
 		.owner = THIS_MODULE,
 		.of_match_table = wm8960_of_match,
+		.pm = &wm8960_pm,
 	},
 	.probe =    wm8960_i2c_probe,
 	.remove =   wm8960_i2c_remove,