ASoC: cs35l56: Update hibernate/wake sequences and

Merge series from Richard Fitzgerald <rf@opensource.cirrus.com>:

Update the hibernate and wake command sequences to meet the latest
datasheet specification and enable hibernation for I2C and SPI control
interfaces.

Richard Fitzgerald (1):
  ASoC: cs35l56: Enable low-power hibernation mode on SPI

Simon Trimmer (3):
  ASoC: cs35l56: Change hibernate sequence to use allow auto hibernate
  ASoC: cs35l56: Wake transactions need to be issued twice
  ASoC: cs35l56: Enable low-power hibernation mode on i2c

 include/sound/cs35l56.h           |  1 +
 sound/soc/codecs/cs35l56-i2c.c    |  1 +
 sound/soc/codecs/cs35l56-shared.c | 66 +++++++++++++++++++------------
 sound/soc/codecs/cs35l56-spi.c    |  1 +
 4 files changed, 43 insertions(+), 26 deletions(-)

--
2.30.2

include/sound/cs35l56.h

@@ -243,6 +243,7 @@
 #define CS35L56_HALO_STATE_POLL_US			1000
 #define CS35L56_HALO_STATE_TIMEOUT_US			50000
 #define CS35L56_RESET_PULSE_MIN_US			1100
+#define CS35L56_WAKE_HOLD_TIME_US			1000
 
 #define CS35L56_SDW1_PLAYBACK_PORT			1
 #define CS35L56_SDW1_CAPTURE_PORT			3

sound/soc/codecs/cs35l56-i2c.c

@@ -27,6 +27,7 @@ static int cs35l56_i2c_probe(struct i2c_client *client)
 		return -ENOMEM;
 
 	cs35l56->base.dev = dev;
+	cs35l56->base.can_hibernate = true;
 
 	i2c_set_clientdata(client, cs35l56);
 	cs35l56->base.regmap = devm_regmap_init_i2c(client, regmap_config);

sound/soc/codecs/cs35l56-shared.c

@@ -439,13 +439,39 @@ EXPORT_SYMBOL_NS_GPL(cs35l56_is_fw_reload_needed, SND_SOC_CS35L56_SHARED);
 
 static const struct reg_sequence cs35l56_hibernate_seq[] = {
 	/* This must be the last register access */
-	REG_SEQ0(CS35L56_DSP_VIRTUAL1_MBOX_1, CS35L56_MBOX_CMD_HIBERNATE_NOW),
+	REG_SEQ0(CS35L56_DSP_VIRTUAL1_MBOX_1, CS35L56_MBOX_CMD_ALLOW_AUTO_HIBERNATE),
 };
 
 static const struct reg_sequence cs35l56_hibernate_wake_seq[] = {
 	REG_SEQ0(CS35L56_DSP_VIRTUAL1_MBOX_1, CS35L56_MBOX_CMD_WAKEUP),
 };
 
+static void cs35l56_issue_wake_event(struct cs35l56_base *cs35l56_base)
+{
+	/*
+	 * Dummy transactions to trigger I2C/SPI auto-wake. Issue two
+	 * transactions to meet the minimum required time from the rising edge
+	 * to the last falling edge of wake.
+	 *
+	 * It uses bypassed write because we must wake the chip before
+	 * disabling regmap cache-only.
+	 *
+	 * This can NAK on I2C which will terminate the write sequence so the
+	 * single-write sequence is issued twice.
+	 */
+	regmap_multi_reg_write_bypassed(cs35l56_base->regmap,
+					cs35l56_hibernate_wake_seq,
+					ARRAY_SIZE(cs35l56_hibernate_wake_seq));
+
+	usleep_range(CS35L56_WAKE_HOLD_TIME_US, 2 * CS35L56_WAKE_HOLD_TIME_US);
+
+	regmap_multi_reg_write_bypassed(cs35l56_base->regmap,
+					cs35l56_hibernate_wake_seq,
+					ARRAY_SIZE(cs35l56_hibernate_wake_seq));
+
+	cs35l56_wait_control_port_ready();
+}
+
 int cs35l56_runtime_suspend_common(struct cs35l56_base *cs35l56_base)
 {
 	unsigned int val;
@@ -473,12 +499,6 @@ int cs35l56_runtime_suspend_common(struct cs35l56_base *cs35l56_base)
 		return 0;
 	}
 
-	/*
-	 * Enable auto-hibernate. If it is woken by some other wake source
-	 * it will automatically return to hibernate.
-	 */
-	cs35l56_mbox_send(cs35l56_base, CS35L56_MBOX_CMD_ALLOW_AUTO_HIBERNATE);
-
 	/*
 	 * Must enter cache-only first so there can't be any more register
 	 * accesses other than the controlled hibernate sequence below.
@@ -506,17 +526,9 @@ int cs35l56_runtime_resume_common(struct cs35l56_base *cs35l56_base, bool is_sou
 	if (!cs35l56_base->can_hibernate)
 		goto out_sync;
 
-	if (!is_soundwire) {
-		/*
-		 * Dummy transaction to trigger I2C/SPI auto-wake. This will NAK on I2C.
-		 * Must be done before releasing cache-only.
-		 */
-		regmap_multi_reg_write_bypassed(cs35l56_base->regmap,
-						cs35l56_hibernate_wake_seq,
-						ARRAY_SIZE(cs35l56_hibernate_wake_seq));
-
-		cs35l56_wait_control_port_ready();
-	}
+	/* Must be done before releasing cache-only */
+	if (!is_soundwire)
+		cs35l56_issue_wake_event(cs35l56_base);
 
 out_sync:
 	regcache_cache_only(cs35l56_base->regmap, false);
@@ -545,11 +557,12 @@ int cs35l56_runtime_resume_common(struct cs35l56_base *cs35l56_base, bool is_sou
 	return 0;
 
 err:
-	regmap_write(cs35l56_base->regmap, CS35L56_DSP_VIRTUAL1_MBOX_1,
-		     CS35L56_MBOX_CMD_HIBERNATE_NOW);
-
 	regcache_cache_only(cs35l56_base->regmap, true);
 
+	regmap_multi_reg_write_bypassed(cs35l56_base->regmap,
+					cs35l56_hibernate_seq,
+					ARRAY_SIZE(cs35l56_hibernate_seq));
+
 	return ret;
 }
 EXPORT_SYMBOL_NS_GPL(cs35l56_runtime_resume_common, SND_SOC_CS35L56_SHARED);
@@ -583,13 +596,14 @@ int cs35l56_hw_init(struct cs35l56_base *cs35l56_base)
 	unsigned int devid, revid, otpid, secured;
 
 	/*
-	 * If the system is not using a reset_gpio then issue a
-	 * dummy read to force a wakeup.
+	 * When the system is not using a reset_gpio ensure the device is
+	 * awake, otherwise the device has just been released from reset and
+	 * the driver must wait for the control port to become usable.
 	 */
 	if (!cs35l56_base->reset_gpio)
-		regmap_read(cs35l56_base->regmap, CS35L56_DSP_VIRTUAL1_MBOX_1, &devid);
-
-	cs35l56_wait_control_port_ready();
+		cs35l56_issue_wake_event(cs35l56_base);
+	else
+		cs35l56_wait_control_port_ready();
 
 	/*
 	 * The HALO_STATE register is in different locations on Ax and B0

sound/soc/codecs/cs35l56-spi.c

@@ -32,6 +32,7 @@ static int cs35l56_spi_probe(struct spi_device *spi)
 	}
 
 	cs35l56->base.dev = &spi->dev;
+	cs35l56->base.can_hibernate = true;
 
 	ret = cs35l56_common_probe(cs35l56);
 	if (ret != 0)