[alsa-devel] [PATCH V3 05/15] ASoC: samsung: i2s: Move clk enable to the platform driver probe()

[Sylwester Nawrocki]

The clk_prepare_enable() call on the "iis" clock is moved to happen earlier
in the DAI platform device driver's probe() callback, so the I2S registers
can be safely accessed through the clk API, after the clk supplier is
registered in the platform device probe().

After this patch the "iis" clock is kept enabled since the (primary) I2S
platform device probe() and until the platform device driver remove() call.
This is similar to gating the clock in the snd_soc_dai probe() and remove()
callbacks.
Normally, in addition to that we should mark the device as PM runtime active,
so if runtime PM is enabled it can idle the device by turning off the clock.
Correcting this issue is left for a separate patch series, as we need to
ensure the BUSCLK clock is always enabled when required.

Signed-off-by: Sylwester Nawrocki <s.nawrocki at samsung.com>
---
 sound/soc/samsung/i2s.c |   25 +++++++++++--------------
 1 file changed, 11 insertions(+), 14 deletions(-)

diff --git a/sound/soc/samsung/i2s.c b/sound/soc/samsung/i2s.c
index a854ffc..f75c19e 100644
--- a/sound/soc/samsung/i2s.c
+++ b/sound/soc/samsung/i2s.c
@@ -969,7 +969,6 @@ static int samsung_i2s_dai_probe(struct snd_soc_dai *dai)
 {
 	struct i2s_dai *i2s = to_info(dai);
 	struct i2s_dai *other = i2s->pri_dai ? : i2s->sec_dai;
-	int ret;
 
 	if (is_secondary(i2s)) { /* If this is probe on the secondary DAI */
 		samsung_asoc_init_dma_data(dai, &other->sec_dai->dma_playback,
@@ -977,12 +976,6 @@ static int samsung_i2s_dai_probe(struct snd_soc_dai *dai)
 		goto probe_exit;
 	}
 
-	ret = clk_prepare_enable(i2s->clk);
-	if (ret != 0) {
-		dev_err(&i2s->pdev->dev, "failed to enable clock: %d\n", ret);
-		return ret;
-	}
-
 	samsung_asoc_init_dma_data(dai, &i2s->dma_playback, &i2s->dma_capture);
 
 	if (i2s->quirks & QUIRK_NEED_RSTCLR)
@@ -1014,18 +1007,12 @@ probe_exit:
 static int samsung_i2s_dai_remove(struct snd_soc_dai *dai)
 {
 	struct i2s_dai *i2s = snd_soc_dai_get_drvdata(dai);
-	struct i2s_dai *other = i2s->pri_dai ? : i2s->sec_dai;
-
-	if (!other || !other->clk) {
 
+	if (!is_secondary(i2s)) {
 		if (i2s->quirks & QUIRK_NEED_RSTCLR)
 			writel(0, i2s->addr + I2SCON);
-
-		clk_disable_unprepare(i2s->clk);
 	}
 
-	i2s->clk = NULL;
-
 	return 0;
 }
 
@@ -1139,6 +1126,7 @@ static int samsung_i2s_probe(struct platform_device *pdev)
 	u32 regs_base, quirks = 0, idma_addr = 0;
 	struct device_node *np = pdev->dev.of_node;
 	const struct samsung_i2s_dai_data *i2s_dai_data;
+	int ret;
 
 	/* Call during Seconday interface registration */
 	i2s_dai_data = samsung_i2s_get_driver_data(pdev);
@@ -1216,6 +1204,12 @@ static int samsung_i2s_probe(struct platform_device *pdev)
 		dev_err(&pdev->dev, "Failed to get iis clock\n");
 		return PTR_ERR(pri_dai->clk);
 	}
+
+	ret = clk_prepare_enable(pri_dai->clk);
+	if (ret != 0) {
+		dev_err(&pdev->dev, "failed to enable clock: %d\n", ret);
+		return ret;
+	}
 	pri_dai->dma_playback.dma_addr = regs_base + I2STXD;
 	pri_dai->dma_capture.dma_addr = regs_base + I2SRXD;
 	pri_dai->dma_playback.ch_name = "tx";
@@ -1286,6 +1280,9 @@ static int samsung_i2s_remove(struct platform_device *pdev)
 		pm_runtime_disable(&pdev->dev);
 	}
 
+	if (!is_secondary(i2s))
+		clk_disable_unprepare(i2s->clk);
+
 	i2s->pri_dai = NULL;
 	i2s->sec_dai = NULL;
 
-- 
1.7.9.5