ASoC: cs35l56: Fixes to handling of ASP1 config

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

This chain fixes some problems with some previous patches for handling
the ASP1 config registers. The root of the problem is that the ownership
of these registers can be either with the firmware or the driver, and that
the chip has to be soft-reset after downloading the firmware.

This chain adds and uses a regmap_read_bypassed() function so that the
driver can leave the regmap in cache-only until the chip has rebooted,
but still poll a register to detect when the chip has rebooted.

Richard Fitzgerald (4):
  regmap: Add regmap_read_bypassed()
  ALSA: hda: cs35l56: Exit cache-only after
    cs35l56_wait_for_firmware_boot()
  ASoC: cs35l56: Fix unintended bus access while resetting amp
  ASoC: cs35l56: Prevent overwriting firmware ASP config

 drivers/base/regmap/regmap.c      | 37 ++++++++++++++
 include/linux/regmap.h            |  8 +++
 include/sound/cs35l56.h           |  2 +
 sound/pci/hda/cs35l56_hda.c       |  4 ++
 sound/soc/codecs/cs35l56-sdw.c    |  2 -
 sound/soc/codecs/cs35l56-shared.c | 83 ++++++++++++++++++++-----------
 sound/soc/codecs/cs35l56.c        | 26 +++++++++-
 7 files changed, 130 insertions(+), 32 deletions(-)

--
2.39.2

3 files changed, 79 insertions, 32 deletions

diff --git a/sound/soc/codecs/cs35l56-sdw.c b/sound/soc/codecs/cs35l56-sdw.c
index 14a5f86019aad..70ff55c1517fe 100644
--- a/sound/soc/codecs/cs35l56-sdw.c
+++ b/sound/soc/codecs/cs35l56-sdw.c
@@ -188,8 +188,6 @@ static void cs35l56_sdw_init(struct sdw_slave *peripheral)
 			goto out;
 	}
 
-	regcache_cache_only(cs35l56->base.regmap, false);
-
 	ret = cs35l56_init(cs35l56);
 	if (ret < 0) {
 		regcache_cache_only(cs35l56->base.regmap, true);
diff --git a/sound/soc/codecs/cs35l56-shared.c b/sound/soc/codecs/cs35l56-shared.c
index 08cac58e3ab22..ec1d95e570615 100644
--- a/sound/soc/codecs/cs35l56-shared.c
+++ b/sound/soc/codecs/cs35l56-shared.c
@@ -40,16 +40,11 @@ EXPORT_SYMBOL_NS_GPL(cs35l56_set_patch, SND_SOC_CS35L56_SHARED);
 static const struct reg_default cs35l56_reg_defaults[] = {
 	/* no defaults for OTP_MEM - first read populates cache */
 
-	{ CS35L56_ASP1_ENABLES1,		0x00000000 },
-	{ CS35L56_ASP1_CONTROL1,		0x00000028 },
-	{ CS35L56_ASP1_CONTROL2,		0x18180200 },
-	{ CS35L56_ASP1_CONTROL3,		0x00000002 },
-	{ CS35L56_ASP1_FRAME_CONTROL1,		0x03020100 },
-	{ CS35L56_ASP1_FRAME_CONTROL5,		0x00020100 },
-	{ CS35L56_ASP1_DATA_CONTROL1,		0x00000018 },
-	{ CS35L56_ASP1_DATA_CONTROL5,		0x00000018 },
-
-	/* no defaults for ASP1TX mixer */
+	/*
+	 * No defaults for ASP1 control or ASP1TX mixer. See
+	 * cs35l56_populate_asp1_register_defaults() and
+	 * cs35l56_sync_asp1_mixer_widgets_with_firmware().
+	 */
 
 	{ CS35L56_SWIRE_DP3_CH1_INPUT,		0x00000018 },
 	{ CS35L56_SWIRE_DP3_CH2_INPUT,		0x00000019 },
@@ -210,6 +205,36 @@ static bool cs35l56_volatile_reg(struct device *dev, unsigned int reg)
 	}
 }
 
+static const struct reg_sequence cs35l56_asp1_defaults[] = {
+	REG_SEQ0(CS35L56_ASP1_ENABLES1,		0x00000000),
+	REG_SEQ0(CS35L56_ASP1_CONTROL1,		0x00000028),
+	REG_SEQ0(CS35L56_ASP1_CONTROL2,		0x18180200),
+	REG_SEQ0(CS35L56_ASP1_CONTROL3,		0x00000002),
+	REG_SEQ0(CS35L56_ASP1_FRAME_CONTROL1,	0x03020100),
+	REG_SEQ0(CS35L56_ASP1_FRAME_CONTROL5,	0x00020100),
+	REG_SEQ0(CS35L56_ASP1_DATA_CONTROL1,	0x00000018),
+	REG_SEQ0(CS35L56_ASP1_DATA_CONTROL5,	0x00000018),
+};
+
+/*
+ * The firmware can have control of the ASP so we don't provide regmap
+ * with defaults for these registers, to prevent a regcache_sync() from
+ * overwriting the firmware settings. But if the machine driver hooks up
+ * the ASP it means the driver is taking control of the ASP, so then the
+ * registers are populated with the defaults.
+ */
+int cs35l56_init_asp1_regs_for_driver_control(struct cs35l56_base *cs35l56_base)
+{
+	if (!cs35l56_base->fw_owns_asp1)
+		return 0;
+
+	cs35l56_base->fw_owns_asp1 = false;
+
+	return regmap_multi_reg_write(cs35l56_base->regmap, cs35l56_asp1_defaults,
+				      ARRAY_SIZE(cs35l56_asp1_defaults));
+}
+EXPORT_SYMBOL_NS_GPL(cs35l56_init_asp1_regs_for_driver_control, SND_SOC_CS35L56_SHARED);
+
 /*
  * The firmware boot sequence can overwrite the ASP1 config registers so that
  * they don't match regmap's view of their values. Rewrite the values from the
@@ -217,19 +242,15 @@ static bool cs35l56_volatile_reg(struct device *dev, unsigned int reg)
  */
 int cs35l56_force_sync_asp1_registers_from_cache(struct cs35l56_base *cs35l56_base)
 {
-	struct reg_sequence asp1_regs[] = {
-		{ .reg = CS35L56_ASP1_ENABLES1 },
-		{ .reg = CS35L56_ASP1_CONTROL1 },
-		{ .reg = CS35L56_ASP1_CONTROL2 },
-		{ .reg = CS35L56_ASP1_CONTROL3 },
-		{ .reg = CS35L56_ASP1_FRAME_CONTROL1 },
-		{ .reg = CS35L56_ASP1_FRAME_CONTROL5 },
-		{ .reg = CS35L56_ASP1_DATA_CONTROL1 },
-		{ .reg = CS35L56_ASP1_DATA_CONTROL5 },
-	};
+	struct reg_sequence asp1_regs[ARRAY_SIZE(cs35l56_asp1_defaults)];
 	int i, ret;
 
-	/* Read values from regmap cache into a write sequence */
+	if (cs35l56_base->fw_owns_asp1)
+		return 0;
+
+	memcpy(asp1_regs, cs35l56_asp1_defaults, sizeof(asp1_regs));
+
+	/* Read current values from regmap cache into the write sequence */
 	for (i = 0; i < ARRAY_SIZE(asp1_regs); ++i) {
 		ret = regmap_read(cs35l56_base->regmap, asp1_regs[i].reg, &asp1_regs[i].def);
 		if (ret)
@@ -307,10 +328,10 @@ int cs35l56_wait_for_firmware_boot(struct cs35l56_base *cs35l56_base)
 		reg = CS35L56_DSP1_HALO_STATE;
 
 	/*
-	 * This can't be a regmap_read_poll_timeout() because cs35l56 will NAK
-	 * I2C until it has booted which would terminate the poll
+	 * The regmap must remain in cache-only until the chip has
+	 * booted, so use a bypassed read of the status register.
 	 */
-	poll_ret = read_poll_timeout(regmap_read, read_ret,
+	poll_ret = read_poll_timeout(regmap_read_bypassed, read_ret,
 				     (val < 0xFFFF) && (val >= CS35L56_HALO_STATE_BOOT_DONE),
 				     CS35L56_HALO_STATE_POLL_US,
 				     CS35L56_HALO_STATE_TIMEOUT_US,
@@ -362,7 +383,8 @@ void cs35l56_system_reset(struct cs35l56_base *cs35l56_base, bool is_soundwire)
 		return;
 
 	cs35l56_wait_control_port_ready();
-	regcache_cache_only(cs35l56_base->regmap, false);
+
+	/* Leave in cache-only. This will be revoked when the chip has rebooted. */
 }
 EXPORT_SYMBOL_NS_GPL(cs35l56_system_reset, SND_SOC_CS35L56_SHARED);
 
@@ -577,14 +599,14 @@ int cs35l56_runtime_resume_common(struct cs35l56_base *cs35l56_base, bool is_sou
 		cs35l56_issue_wake_event(cs35l56_base);
 
 out_sync:
-	regcache_cache_only(cs35l56_base->regmap, false);
-
 	ret = cs35l56_wait_for_firmware_boot(cs35l56_base);
 	if (ret) {
 		dev_err(cs35l56_base->dev, "Hibernate wake failed: %d\n", ret);
 		goto err;
 	}
 
+	regcache_cache_only(cs35l56_base->regmap, false);
+
 	ret = cs35l56_mbox_send(cs35l56_base, CS35L56_MBOX_CMD_PREVENT_AUTO_HIBERNATE);
 	if (ret)
 		goto err;
@@ -757,7 +779,7 @@ int cs35l56_hw_init(struct cs35l56_base *cs35l56_base)
 	 * devices so the REVID needs to be determined before waiting for the
 	 * firmware to boot.
 	 */
-	ret = regmap_read(cs35l56_base->regmap, CS35L56_REVID, &revid);
+	ret = regmap_read_bypassed(cs35l56_base->regmap, CS35L56_REVID, &revid);
 	if (ret < 0) {
 		dev_err(cs35l56_base->dev, "Get Revision ID failed\n");
 		return ret;
@@ -768,7 +790,7 @@ int cs35l56_hw_init(struct cs35l56_base *cs35l56_base)
 	if (ret)
 		return ret;
 
-	ret = regmap_read(cs35l56_base->regmap, CS35L56_DEVID, &devid);
+	ret = regmap_read_bypassed(cs35l56_base->regmap, CS35L56_DEVID, &devid);
 	if (ret < 0) {
 		dev_err(cs35l56_base->dev, "Get Device ID failed\n");
 		return ret;
@@ -787,6 +809,9 @@ int cs35l56_hw_init(struct cs35l56_base *cs35l56_base)
 
 	cs35l56_base->type = devid & 0xFF;
 
+	/* Silicon is now identified and booted so exit cache-only */
+	regcache_cache_only(cs35l56_base->regmap, false);
+
 	ret = regmap_read(cs35l56_base->regmap, CS35L56_DSP_RESTRICT_STS1, &secured);
 	if (ret) {
 		dev_err(cs35l56_base->dev, "Get Secure status failed\n");
diff --git a/sound/soc/codecs/cs35l56.c b/sound/soc/codecs/cs35l56.c
index 8d2f021fb3628..6331b8c6136ea 100644
--- a/sound/soc/codecs/cs35l56.c
+++ b/sound/soc/codecs/cs35l56.c
@@ -454,9 +454,14 @@ static int cs35l56_asp_dai_set_fmt(struct snd_soc_dai *codec_dai, unsigned int f
 {
 	struct cs35l56_private *cs35l56 = snd_soc_component_get_drvdata(codec_dai->component);
 	unsigned int val;
+	int ret;
 
 	dev_dbg(cs35l56->base.dev, "%s: %#x\n", __func__, fmt);
 
+	ret = cs35l56_init_asp1_regs_for_driver_control(&cs35l56->base);
+	if (ret)
+		return ret;
+
 	switch (fmt & SND_SOC_DAIFMT_CLOCK_PROVIDER_MASK) {
 	case SND_SOC_DAIFMT_CBC_CFC:
 		break;
@@ -530,6 +535,11 @@ static int cs35l56_asp_dai_set_tdm_slot(struct snd_soc_dai *dai, unsigned int tx
 					unsigned int rx_mask, int slots, int slot_width)
 {
 	struct cs35l56_private *cs35l56 = snd_soc_component_get_drvdata(dai->component);
+	int ret;
+
+	ret = cs35l56_init_asp1_regs_for_driver_control(&cs35l56->base);
+	if (ret)
+		return ret;
 
 	if ((slots == 0) || (slot_width == 0)) {
 		dev_dbg(cs35l56->base.dev, "tdm config cleared\n");
@@ -578,6 +588,11 @@ static int cs35l56_asp_dai_hw_params(struct snd_pcm_substream *substream,
 	struct cs35l56_private *cs35l56 = snd_soc_component_get_drvdata(dai->component);
 	unsigned int rate = params_rate(params);
 	u8 asp_width, asp_wl;
+	int ret;
+
+	ret = cs35l56_init_asp1_regs_for_driver_control(&cs35l56->base);
+	if (ret)
+		return ret;
 
 	asp_wl = params_width(params);
 	if (cs35l56->asp_slot_width)
@@ -634,7 +649,11 @@ static int cs35l56_asp_dai_set_sysclk(struct snd_soc_dai *dai,
 				      int clk_id, unsigned int freq, int dir)
 {
 	struct cs35l56_private *cs35l56 = snd_soc_component_get_drvdata(dai->component);
-	int freq_id;
+	int freq_id, ret;
+
+	ret = cs35l56_init_asp1_regs_for_driver_control(&cs35l56->base);
+	if (ret)
+		return ret;
 
 	if (freq == 0) {
 		cs35l56->sysclk_set = false;
@@ -1403,6 +1422,9 @@ int cs35l56_common_probe(struct cs35l56_private *cs35l56)
 	cs35l56->base.cal_index = -1;
 	cs35l56->speaker_id = -ENOENT;
 
+	/* Assume that the firmware owns ASP1 until we know different */
+	cs35l56->base.fw_owns_asp1 = true;
+
 	dev_set_drvdata(cs35l56->base.dev, cs35l56);
 
 	cs35l56_fill_supply_names(cs35l56->supplies);
@@ -1531,6 +1553,8 @@ post_soft_reset:
 			return ret;
 
 		dev_dbg(cs35l56->base.dev, "Firmware rebooted after soft reset\n");
+
+		regcache_cache_only(cs35l56->base.regmap, false);
 	}
 
 	/* Disable auto-hibernate so that runtime_pm has control */