ASoC: cs-amp-lib: Add helpers for factory calibration data

Create a new library for code that is used by multiple Cirrus Logic
amps. This initially implements extracting amp calibration data
from EFI and writing it to firmware controls.

During factory calibration of built-in speakers the firmware
calibration constants are stored in an EFI file. The file contains
an array of calibration constants for each of the speakers.
cs_amp_get_calibration_data() searches for an entry matching the
requested UID stamp, otherwise by array index. If the data is found in
EFI the constants for that speaker are copied back to the caller.

If EFI is not enabled, the cs_amp_get_calibration_data() implementation
will compile to simply return -ENOENT and the linker can drop the code.

The code to write calibration controls uses cs_dsp. Building of cs_dsp
is not forced. Instead, the code will compile away the calls to
cs_dsp if cs_dsp is not reachable.

This strategy of conditional code allows cs-amp-lib to be shared by
multiple drivers without forcing inclusion of other modules that might
be unnecessary.

The calls to efi.get_variable() and cs_dsp are in small wrapper
functions. This is so that a KUNIT_STATIC_STUB_REDIRECT can be added in
a future patch to redirect these calls to replacement functions for
KUnit testing.

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20240223153910.2063698-3-rf@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 52 insertions, 0 deletions

diff --git a/include/sound/cs-amp-lib.h b/include/sound/cs-amp-lib.h
new file mode 100644
index 000000000000..077fe36885b5
--- /dev/null
+++ b/include/sound/cs-amp-lib.h
@@ -0,0 +1,52 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2024 Cirrus Logic, Inc. and
+ *                    Cirrus Logic International Semiconductor Ltd.
+ */
+
+#ifndef CS_AMP_LIB_H
+#define CS_AMP_LIB_H
+
+#include <linux/efi.h>
+#include <linux/types.h>
+
+struct cs_dsp;
+
+struct cirrus_amp_cal_data {
+	u32 calTarget[2];
+	u32 calTime[2];
+	s8  calAmbient;
+	u8  calStatus;
+	u16 calR;
+} __packed;
+
+struct cirrus_amp_efi_data {
+	u32 size;
+	u32 count;
+	struct cirrus_amp_cal_data data[];
+} __packed;
+
+/**
+ * struct cirrus_amp_cal_controls - definition of firmware calibration controls
+ * @alg_id:	ID of algorithm containing the controls.
+ * @mem_region:	DSP memory region containing the controls.
+ * @ambient:	Name of control for calAmbient value.
+ * @calr:	Name of control for calR value.
+ * @status:	Name of control for calStatus value.
+ * @checksum:	Name of control for checksum value.
+ */
+struct cirrus_amp_cal_controls {
+	unsigned int alg_id;
+	int mem_region;
+	const char *ambient;
+	const char *calr;
+	const char *status;
+	const char *checksum;
+};
+
+int cs_amp_write_cal_coeffs(struct cs_dsp *dsp,
+			    const struct cirrus_amp_cal_controls *controls,
+			    const struct cirrus_amp_cal_data *data);
+int cs_amp_get_efi_calibration_data(struct device *dev, u64 target_uid, int amp_index,
+				    struct cirrus_amp_cal_data *out_data);
+#endif /* CS_AMP_LIB_H */