From 07e21d4d96493fd0a8220ab134855253a34a9c84 Mon Sep 17 00:00:00 2001
From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Date: Wed, 4 Nov 2020 01:22:22 +0800
Subject: [PATCH] soundwire: SDCA: add helper macro to access controls
Git-commit: 07e21d4d96493fd0a8220ab134855253a34a9c84
Patch-mainline: v5.11-rc1
References: jsc#SLE-16518
The upcoming SDCA (SoundWire Device Class Audio) specification defines
a hierarchical encoding to interface with Class-defined capabilities.
The specification is not yet accessible to the general public but this
information is released with explicit permission from the MIPI Board
to avoid delays with SDCA support on Linux platforms.
A block of 64 MBytes of register addresses are allocated to SDCA
controls, starting at address 0x40000000. The 26 LSBs which identify
individual controls are set based on the following variables:
- Function Number. An SCDA device can be split in up to 8 independent
Functions. Each of these Functions is described in the SDCA
specification, e.g. Smart Amplifier, Smart Microphone, Simple
Microphone, Jack codec, HID, etc.
- Entity Number. Within each Function, an Entity is an identifiable
block. Up to 127 Entities are connected in a pre-defined
graph (similar to USB), with Entity0 reserved for Function-level
configurations. In contrast to USB, the SDCA spec pre-defines
Function Types, topologies, and allowed options, i.e. the degree of
freedom is not unlimited to limit the possibility of errors in
descriptors leading to software quirks.
- Control Selector. Within each Entity, the SDCA specification defines
48 controls such as Mute, Gain, AGC, etc, and 16 implementation
defined ones. Some Control Selectors might be used for low-level
platform setup, and other exposed to applications and users. Note
that the same Control Selector capability, e.g. Latency control,
might be located at different offsets in different entities, the
Control Selector mapping is Entity-specific.
- Control Number. Some Control Selectors allow channel-specific values
to be set, with up to 64 channels allowed. This is mostly used for
volume control.
- Current/Next values. Some Control Selectors are
'Dual-Ranked'. Software may either update the Current value directly
for immediate effect. Alternatively, software may write into the
'Next' values and update the SoundWire 1.2 'Commit Groups' register
to copy 'Next' values into 'Current' ones in a synchronized
manner. This is different from bank switching which is typically
used to change the bus configuration only.
- MBQ. the Multi-Byte Quantity bit is used to provide atomic updates
when accessing more that one byte, for example a 16-bit volume
control would be updated consistently, the intermediate values
mixing old MSB with new LSB are not applied.
These 6 parameters are used to build a 32-bit address to access the
desired Controls. Because of address range, paging is required, but
the most often used parameter values are placed in the lower 16 bits
of the address. This helps to keep the paging registers constant while
updating Controls for a specific Device/Function.
Reviewed-by: Rander Wang <rander.wang@linux.intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Acked-by: Vinod Koul <vkoul@kernel.org>
Link: https://lore.kernel.org/r/20201103172226.4278-2-yung-chuan.liao@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
include/linux/soundwire/sdw_registers.h | 32 +++++++++++++++++++++++++
1 file changed, 32 insertions(+)
diff --git a/include/linux/soundwire/sdw_registers.h b/include/linux/soundwire/sdw_registers.h
index f420e8059779..e14dff9a9c7f 100644
--- a/include/linux/soundwire/sdw_registers.h
+++ b/include/linux/soundwire/sdw_registers.h
@@ -298,4 +298,36 @@
#define SDW_CASC_PORT_MASK_INTSTAT3 1
#define SDW_CASC_PORT_REG_OFFSET_INTSTAT3 2
+/*
+ * v1.2 device - SDCA address mapping
+ *
+ * Spec definition
+ * Bits Contents
+ * 31 0 (required by addressing range)
+ * 30:26 0b10000 (Control Prefix)
+ * 25 0 (Reserved)
+ * 24:22 Function Number [2:0]
+ * 21 Entity[6]
+ * 20:19 Control Selector[5:4]
+ * 18 0 (Reserved)
+ * 17:15 Control Number[5:3]
+ * 14 Next
+ * 13 MBQ
+ * 12:7 Entity[5:0]
+ * 6:3 Control Selector[3:0]
+ * 2:0 Control Number[2:0]
+ */
+
+#define SDW_SDCA_CTL(fun, ent, ctl, ch) (BIT(30) | \
+ (((fun) & 0x7) << 22) | \
+ (((ent) & 0x40) << 15) | \
+ (((ent) & 0x3f) << 7) | \
+ (((ctl) & 0x30) << 15) | \
+ (((ctl) & 0x0f) << 3) | \
+ (((ch) & 0x38) << 12) | \
+ ((ch) & 0x07))
+
+#define SDW_SDCA_MBQ_CTL(reg) ((reg) | BIT(13))
+#define SDW_SDCA_NEXT_CTL(reg) ((reg) | BIT(14))
+
#endif /* __SDW_REGISTERS_H */
--
2.26.2