[PATCH v1 1/2] ALSA: hda: cs35l41: Add common wait_for_boot api and reset_and_boot api

[Stefan Binding <sbinding@opensource.cirrus.com>]

Both the ASoC CS35L41 and HDA CS35L41 drivers currently use
regmap_read_poll_timeout() calls to wait for the chip to boot.
However, this macro will exit immediately if one of the regmap_read()
calls fail. This could be cause by the hardware not being ready yet
after a reset, which then breaks the loop early and leads to probe
and resume calls failing.

This patch replaces the existing code in the HDA driver with a
function with a loop which does not break on regmap_read() failure.
Since both drivers need to do this, make a common function in
cs35l41-lib.c to be called from both drivers.
This patch only updates the HDA driver, a separate patch will update
the ASoC driver.

In addition, before the call to wait to boot, the HDA driver also
does a software reset to ensure the device is in a known state before
probe or resume (for example, if there is no reset gpio). Since this
write could fail for the same reason, add a common api to do this
with a retry mechanism.

Signed-off-by: Stefan Binding <sbinding@opensource.cirrus.com>
---
 include/sound/cs35l41.h                    |  2 +
 sound/hda/codecs/side-codecs/cs35l41_hda.c | 33 +----------
 sound/soc/codecs/cs35l41-lib.c             | 67 ++++++++++++++++++++++
 3 files changed, 71 insertions(+), 31 deletions(-)

diff --git a/include/sound/cs35l41.h b/include/sound/cs35l41.h
index 7542cabfa726..b6b338c55ff0 100644
--- a/include/sound/cs35l41.h
+++ b/include/sound/cs35l41.h
@@ -924,5 +924,7 @@ bool cs35l41_safe_reset(struct regmap *regmap, enum cs35l41_boost_type b_type);
 int cs35l41_mdsync_up(struct regmap *regmap);
 int cs35l41_global_enable(struct device *dev, struct regmap *regmap, enum cs35l41_boost_type b_type,
 			  int enable, struct cs_dsp *dsp);
+int cs35l41_wait_boot_done(struct device *dev, struct regmap *regmap);
+int cs35l41_reset_and_boot(struct device *dev, struct regmap *regmap);
 
 #endif /* __CS35L41_H */
diff --git a/sound/hda/codecs/side-codecs/cs35l41_hda.c b/sound/hda/codecs/side-codecs/cs35l41_hda.c
index f879e3ffbb53..23582f23a880 100644
--- a/sound/hda/codecs/side-codecs/cs35l41_hda.c
+++ b/sound/hda/codecs/side-codecs/cs35l41_hda.c
@@ -974,30 +974,6 @@ static int cs35l41_system_suspend(struct device *dev)
 	return ret;
 }
 
-static int cs35l41_wait_boot_done(struct cs35l41_hda *cs35l41)
-{
-	unsigned int int_status;
-	int ret;
-
-	ret = regmap_read_poll_timeout(cs35l41->regmap, CS35L41_IRQ1_STATUS4, int_status,
-				       int_status & CS35L41_OTP_BOOT_DONE, 1000, 100000);
-	if (ret) {
-		dev_err(cs35l41->dev, "Failed waiting for OTP_BOOT_DONE\n");
-		return ret;
-	}
-
-	ret = regmap_read(cs35l41->regmap, CS35L41_IRQ1_STATUS3, &int_status);
-	if (ret || (int_status & CS35L41_OTP_BOOT_ERR)) {
-		dev_err(cs35l41->dev, "OTP Boot status %x error\n",
-			int_status & CS35L41_OTP_BOOT_ERR);
-		if (!ret)
-			ret = -EIO;
-		return ret;
-	}
-
-	return 0;
-}
-
 static int cs35l41_system_resume(struct device *dev)
 {
 	struct cs35l41_hda *cs35l41 = dev_get_drvdata(dev);
@@ -1020,10 +996,7 @@ static int cs35l41_system_resume(struct device *dev)
 
 	regcache_cache_only(cs35l41->regmap, false);
 
-	regmap_write(cs35l41->regmap, CS35L41_SFT_RESET, CS35L41_SOFTWARE_RESET);
-	usleep_range(2000, 2100);
-
-	ret = cs35l41_wait_boot_done(cs35l41);
+	ret = cs35l41_reset_and_boot(cs35l41->dev, cs35l41->regmap);
 	if (ret)
 		return ret;
 
@@ -2003,11 +1976,9 @@ int cs35l41_hda_probe(struct device *dev, const char *device_name, int id, int i
 		gpiod_set_value_cansleep(cs35l41->reset_gpio, 1);
 	}
 
-	usleep_range(2000, 2100);
-	regmap_write(cs35l41->regmap, CS35L41_SFT_RESET, CS35L41_SOFTWARE_RESET);
 	usleep_range(2000, 2100);
 
-	ret = cs35l41_wait_boot_done(cs35l41);
+	ret = cs35l41_reset_and_boot(cs35l41->dev, cs35l41->regmap);
 	if (ret)
 		goto err;
 
diff --git a/sound/soc/codecs/cs35l41-lib.c b/sound/soc/codecs/cs35l41-lib.c
index b0fa80705be7..973713626ebd 100644
--- a/sound/soc/codecs/cs35l41-lib.c
+++ b/sound/soc/codecs/cs35l41-lib.c
@@ -17,6 +17,8 @@
 #include <sound/cs35l41.h>
 
 #define CS35L41_FIRMWARE_OLD_VERSION 0x001C00 /* v0.28.0 */
+#define CS35L41_GLOBAL_BOOT_DONE_TIMEOUT_US 100000
+#define CS35L41_GLOBAL_BOOT_DONE_SLEEP_US 2000
 
 static const struct reg_default cs35l41_reg[] = {
 	{ CS35L41_PWR_CTRL1,			0x00000000 },
@@ -1586,6 +1588,71 @@ int cs35l41_exit_hibernate(struct device *dev, struct regmap *regmap)
 }
 EXPORT_SYMBOL_GPL(cs35l41_exit_hibernate);
 
+int cs35l41_wait_boot_done(struct device *dev, struct regmap *regmap)
+{
+	ktime_t timeout;
+	unsigned int val = 0;
+	int ret = 0;
+
+	/*
+	 * The chip could NAK a read request while it is booting so ignore
+	 * errors from regmap_read.
+	 */
+	timeout = ktime_add_us(ktime_get(), CS35L41_GLOBAL_BOOT_DONE_TIMEOUT_US);
+	regmap_read(regmap, CS35L41_IRQ1_STATUS4, &val);
+	while (!(val & CS35L41_OTP_BOOT_DONE) && !ktime_after(ktime_get(), timeout)) {
+		usleep_range(CS35L41_GLOBAL_BOOT_DONE_SLEEP_US / 2,
+			     CS35L41_GLOBAL_BOOT_DONE_SLEEP_US);
+		regmap_read(regmap, CS35L41_IRQ1_STATUS4, &val);
+	}
+
+	if (!(val & CS35L41_OTP_BOOT_DONE)) {
+		dev_err(dev, "Timeout waiting for OTP_BOOT_DONE\n");
+		return -ETIMEDOUT;
+	}
+
+	ret = regmap_read(regmap, CS35L41_IRQ1_STATUS3, &val);
+	if (ret || (val & CS35L41_OTP_BOOT_ERR)) {
+		dev_err(dev, "OTP Boot status %x error\n",
+			val & CS35L41_OTP_BOOT_ERR);
+		if (!ret)
+			ret = -EIO;
+		return ret;
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(cs35l41_wait_boot_done);
+
+int cs35l41_reset_and_boot(struct device *dev, struct regmap *regmap)
+{
+	int ret;
+
+	ret = regmap_write(regmap, CS35L41_SFT_RESET, CS35L41_SOFTWARE_RESET);
+	if (ret) {
+		dev_warn(dev, "Failed to write software reset: %d\n", ret);
+
+		/*
+		 * If the write failed, it is likely because the chip is still booting after a
+		 * reset. Wait for boot, then retry the software reset. If the initial write failed
+		 * for another reason, then either waiting for boot, or the second write will fail,
+		 * So we can return the error then.
+		 */
+		ret = cs35l41_wait_boot_done(dev, regmap);
+		if (ret)
+			return ret;
+
+		ret = regmap_write(regmap, CS35L41_SFT_RESET, CS35L41_SOFTWARE_RESET);
+		if (ret) {
+			dev_err(dev, "Failed to write software reset on retry: %d\n", ret);
+			return ret;
+		}
+	}
+	usleep_range(2000, 2100);
+
+	return cs35l41_wait_boot_done(dev, regmap);
+}
+EXPORT_SYMBOL_GPL(cs35l41_reset_and_boot);
+
 MODULE_DESCRIPTION("CS35L41 library");
 MODULE_AUTHOR("David Rhodes, Cirrus Logic Inc, <david.rhodes@cirrus.com>");
 MODULE_AUTHOR("Lucas Tanure, Cirrus Logic Inc, <tanureal@opensource.cirrus.com>");
-- 
2.43.0