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From:   Maciej Strozek <mstrozek@opensource.cirrus.com>
To:     Mark Brown <broonie@kernel.org>
CC:     James Schulman <james.schulman@cirrus.com>,
        David Rhodes <david.rhodes@cirrus.com>,
        Liam Girdwood <lgirdwood@gmail.com>,
        <alsa-devel@alsa-project.org>, <patches@opensource.cirrus.com>,
        <linux-sound@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        Maciej Strozek <mstrozek@opensource.cirrus.com>
Subject: [PATCH v5] ASoC: cs43130: Allow driver to work without IRQ connection
Date:   Thu, 23 Nov 2023 09:06:58 +0000
Message-ID: <20231123090658.10418-1-mstrozek@opensource.cirrus.com>
MIME-Version: 1.0
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Precedence: bulk

Add a polling mechanism that will keep the driver operational even in
absence of physical IRQ connection. If IRQ line is detected, the driver
will continue working as usual, in case of missing IRQ line it will
fallback to the polling mechanism introduced in this change.
This will support users which choose not to connect an IRQ line as it
is not critical to part's operation.

Signed-off-by: Maciej Strozek <mstrozek@opensource.cirrus.com>
---
V4 -> V5: Do not use hpload interrupt with the new polling function
V3 -> V4:
	- Removed unnecesary else and indentation
	- Changed cs43130_wait_for_completion return codes and updated callers
	  accordingly
	- Changed approach for checking for presence of IRQ connection: see if
	  client->irq equals 0 which seems to be a standard way of checking it
	  used by other drivers (instead of inspecting
	  devm_request_threaded_irq error code)
V2 -> V3: Amended changelog message and subject line
V1 -> V2: Add changelog message

 sound/soc/codecs/cs43130.c | 77 ++++++++++++++++++++++++++------------
 sound/soc/codecs/cs43130.h |  1 +
 2 files changed, 55 insertions(+), 23 deletions(-)

diff --git a/sound/soc/codecs/cs43130.c b/sound/soc/codecs/cs43130.c
index 02e7f45b9208..0f3ead84665f 100644
--- a/sound/soc/codecs/cs43130.c
+++ b/sound/soc/codecs/cs43130.c
@@ -326,6 +326,34 @@ static int cs43130_set_pll(struct snd_soc_component *component, int pll_id, int
 	return ret;
 }

+static int cs43130_wait_for_completion(struct cs43130_private *cs43130, struct completion *to_poll,
+					int time)
+{
+	int stickies, offset, flag, ret;
+
+	if (cs43130->has_irq_line) {
+		ret = wait_for_completion_timeout(to_poll, msecs_to_jiffies(time));
+		if (ret == 0)
+			return -ETIMEDOUT;
+		else
+			return 0; // Discard number of jiffies left till timeout and return success
+	}
+
+	if (to_poll == &cs43130->xtal_rdy) {
+		offset = 0;
+		flag = CS43130_XTAL_RDY_INT;
+	} else if (to_poll == &cs43130->pll_rdy) {
+		offset = 0;
+		flag = CS43130_PLL_RDY_INT;
+	} else {
+		return -EINVAL;
+	}
+
+	return regmap_read_poll_timeout(cs43130->regmap, CS43130_INT_STATUS_1 + offset,
+					stickies, (stickies & flag),
+					1000, time * 1000);
+}
+
 static int cs43130_change_clksrc(struct snd_soc_component *component,
 				 enum cs43130_mclk_src_sel src)
 {
@@ -364,14 +392,13 @@ static int cs43130_change_clksrc(struct snd_soc_component *component,
 					   CS43130_XTAL_RDY_INT_MASK, 0);
 			regmap_update_bits(cs43130->regmap, CS43130_PWDN_CTL,
 					   CS43130_PDN_XTAL_MASK, 0);
-			ret = wait_for_completion_timeout(&cs43130->xtal_rdy,
-							  msecs_to_jiffies(100));
+			ret = cs43130_wait_for_completion(cs43130, &cs43130->xtal_rdy, 100);
 			regmap_update_bits(cs43130->regmap, CS43130_INT_MASK_1,
 					   CS43130_XTAL_RDY_INT_MASK,
 					   1 << CS43130_XTAL_RDY_INT_SHIFT);
-			if (ret == 0) {
-				dev_err(cs43130->dev, "Timeout waiting for XTAL_READY interrupt\n");
-				return -ETIMEDOUT;
+			if (ret) {
+				dev_err(cs43130->dev, "Error waiting for XTAL_READY interrupt: %d\n", ret);
+				return ret;
 			}
 		}

@@ -400,14 +427,13 @@ static int cs43130_change_clksrc(struct snd_soc_component *component,
 					   CS43130_XTAL_RDY_INT_MASK, 0);
 			regmap_update_bits(cs43130->regmap, CS43130_PWDN_CTL,
 					   CS43130_PDN_XTAL_MASK, 0);
-			ret = wait_for_completion_timeout(&cs43130->xtal_rdy,
-							  msecs_to_jiffies(100));
+			ret = cs43130_wait_for_completion(cs43130, &cs43130->xtal_rdy, 100);
 			regmap_update_bits(cs43130->regmap, CS43130_INT_MASK_1,
 					   CS43130_XTAL_RDY_INT_MASK,
 					   1 << CS43130_XTAL_RDY_INT_SHIFT);
-			if (ret == 0) {
-				dev_err(cs43130->dev, "Timeout waiting for XTAL_READY interrupt\n");
-				return -ETIMEDOUT;
+			if (ret) {
+				dev_err(cs43130->dev, "Error waiting for XTAL_READY interrupt: %d\n", ret);
+				return ret;
 			}
 		}

@@ -416,14 +442,13 @@ static int cs43130_change_clksrc(struct snd_soc_component *component,
 				   CS43130_PLL_RDY_INT_MASK, 0);
 		regmap_update_bits(cs43130->regmap, CS43130_PWDN_CTL,
 				   CS43130_PDN_PLL_MASK, 0);
-		ret = wait_for_completion_timeout(&cs43130->pll_rdy,
-						  msecs_to_jiffies(100));
+		ret = cs43130_wait_for_completion(cs43130, &cs43130->pll_rdy, 100);
 		regmap_update_bits(cs43130->regmap, CS43130_INT_MASK_1,
 				   CS43130_PLL_RDY_INT_MASK,
 				   1 << CS43130_PLL_RDY_INT_SHIFT);
-		if (ret == 0) {
-			dev_err(cs43130->dev, "Timeout waiting for PLL_READY interrupt\n");
-			return -ETIMEDOUT;
+		if (ret) {
+			dev_err(cs43130->dev, "Error waiting for PLL_READY interrupt: %d\n", ret);
+			return ret;
 		}

 		regmap_update_bits(cs43130->regmap, CS43130_SYS_CLK_CTL_1,
@@ -2053,7 +2078,7 @@ static int cs43130_hpload_proc(struct cs43130_private *cs43130,
 	regmap_read(cs43130->regmap, CS43130_INT_MASK_4, &msk);
 	if (!ret) {
 		dev_err(cs43130->dev, "Timeout waiting for HPLOAD interrupt\n");
-		return -1;
+		return -ETIMEDOUT;
 	}

 	dev_dbg(cs43130->dev, "HP load stat: %x, INT_MASK_4: %x\n",
@@ -2548,13 +2573,19 @@ static int cs43130_i2c_probe(struct i2c_client *client)
 	init_completion(&cs43130->pll_rdy);
 	init_completion(&cs43130->hpload_evt);

-	ret = devm_request_threaded_irq(cs43130->dev, client->irq,
-					NULL, cs43130_irq_thread,
-					IRQF_ONESHOT | IRQF_TRIGGER_LOW,
-					"cs43130", cs43130);
-	if (ret != 0) {
-		dev_err(cs43130->dev, "Failed to request IRQ: %d\n", ret);
-		goto err;
+	if (!client->irq) {
+		dev_dbg(cs43130->dev, "IRQ not found, will poll instead\n");
+		cs43130->has_irq_line = 0;
+	} else {
+		ret = devm_request_threaded_irq(cs43130->dev, client->irq,
+						NULL, cs43130_irq_thread,
+						IRQF_ONESHOT | IRQF_TRIGGER_LOW,
+						"cs43130", cs43130);
+		if (ret != 0) {
+			dev_err(cs43130->dev, "Failed to request IRQ: %d\n", ret);
+			goto err;
+		}
+		cs43130->has_irq_line = 1;
 	}

 	cs43130->mclk_int_src = CS43130_MCLK_SRC_RCO;
diff --git a/sound/soc/codecs/cs43130.h b/sound/soc/codecs/cs43130.h
index d3f595bbd3ba..dbdb5b262f1b 100644
--- a/sound/soc/codecs/cs43130.h
+++ b/sound/soc/codecs/cs43130.h
@@ -508,6 +508,7 @@ struct	cs43130_private {
 	struct gpio_desc		*reset_gpio;
 	unsigned int			dev_id; /* codec device ID */
 	int				xtal_ibias;
+	bool				has_irq_line;

 	/* shared by both DAIs */
 	struct mutex			clk_mutex;
--
2.34.1