ASoC: cs35l56: Log a message if firmware is missing

If the amp is still reporting FIRMWARE_MISSING after cs35l56_patch()
has completed it is helpful to log a warning.

After a complete firmware download the FIRMWARE_MISSING flag will be
clear. If this isn't the case, the driver should log a message to
report this.

The amp can produce basic audio output without firmware, as a fallback,
so this wasn't originally logged as a warning condition because the amp
is still in an operational state - just not with full functionality.
However, it was not at all obvious to an end user that anything is
unusual.

Signed-off-by: Richard Fitzgerald <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

include/sound/cs35l56.h

···
 			       struct snd_ctl_elem_value *uvalue);
 int cs35l56_read_prot_status(struct cs35l56_base *cs35l56_base,
 			     bool *fw_missing, unsigned int *fw_version);
+void cs35l56_warn_if_firmware_missing(struct cs35l56_base *cs35l56_base);
 void cs35l56_log_tuning(struct cs35l56_base *cs35l56_base, struct cs_dsp *cs_dsp);
 int cs35l56_hw_init(struct cs35l56_base *cs35l56_base);
 int cs35l56_get_speaker_id(struct cs35l56_base *cs35l56_base);

sound/soc/codecs/cs35l56-shared.c

···
 }
 EXPORT_SYMBOL_NS_GPL(cs35l56_read_prot_status, "SND_SOC_CS35L56_SHARED");
 
+void cs35l56_warn_if_firmware_missing(struct cs35l56_base *cs35l56_base)
+{
+	unsigned int firmware_version;
+	bool firmware_missing;
+	int ret;
+
+	ret = cs35l56_read_prot_status(cs35l56_base, &firmware_missing, &firmware_version);
+	if (ret)
+		return;
+
+	if (!firmware_missing)
+		return;
+
+	dev_warn(cs35l56_base->dev, "FIRMWARE_MISSING\n");
+}
+EXPORT_SYMBOL_NS_GPL(cs35l56_warn_if_firmware_missing, "SND_SOC_CS35L56_SHARED");
+
 void cs35l56_log_tuning(struct cs35l56_base *cs35l56_base, struct cs_dsp *cs_dsp)
 {
 	__be32 pid, sid, tid;

sound/soc/codecs/cs35l56.c

···
 		goto err_unlock;
 	}
 
+	/* Check if the firmware is still reported missing */
+	cs35l56_warn_if_firmware_missing(&cs35l56->base);
+
 	regmap_clear_bits(cs35l56->base.regmap,
 			  cs35l56->base.fw_reg->prot_sts,
 			  CS35L56_FIRMWARE_MISSING);