SoundWire: add MBQ support in regmap

drivers/base/regmap/Kconfig

@@ -4,7 +4,7 @@
 # subsystems should select the appropriate symbols.
 
 config REGMAP
-	default y if (REGMAP_I2C || REGMAP_SPI || REGMAP_SPMI || REGMAP_W1 || REGMAP_AC97 || REGMAP_MMIO || REGMAP_IRQ || REGMAP_SOUNDWIRE || REGMAP_SCCB || REGMAP_I3C)
+	default y if (REGMAP_I2C || REGMAP_SPI || REGMAP_SPMI || REGMAP_W1 || REGMAP_AC97 || REGMAP_MMIO || REGMAP_IRQ || REGMAP_SOUNDWIRE || REGMAP_SOUNDWIRE_MBQ || REGMAP_SCCB || REGMAP_I3C)
 	select IRQ_DOMAIN if REGMAP_IRQ
 	bool
 
@@ -46,6 +46,10 @@ config REGMAP_SOUNDWIRE
 	tristate
 	depends on SOUNDWIRE
 
+config REGMAP_SOUNDWIRE_MBQ
+	tristate
+	depends on SOUNDWIRE
+
 config REGMAP_SCCB
 	tristate
 	depends on I2C

drivers/base/regmap/Makefile

@@ -15,5 +15,6 @@ obj-$(CONFIG_REGMAP_MMIO) += regmap-mmio.o
 obj-$(CONFIG_REGMAP_IRQ) += regmap-irq.o
 obj-$(CONFIG_REGMAP_W1) += regmap-w1.o
 obj-$(CONFIG_REGMAP_SOUNDWIRE) += regmap-sdw.o
+obj-$(CONFIG_REGMAP_SOUNDWIRE_MBQ) += regmap-sdw-mbq.o
 obj-$(CONFIG_REGMAP_SCCB) += regmap-sccb.o
 obj-$(CONFIG_REGMAP_I3C) += regmap-i3c.o

drivers/base/regmap/regmap-sdw-mbq.c

@@ -0,0 +1,102 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright(c) 2020 Intel Corporation.
+
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/soundwire/sdw.h>
+#include <linux/soundwire/sdw_registers.h>
+#include "internal.h"
+
+static int regmap_sdw_mbq_write(void *context, unsigned int reg, unsigned int val)
+{
+	struct device *dev = context;
+	struct sdw_slave *slave = dev_to_sdw_dev(dev);
+	int ret;
+
+	ret = sdw_write(slave, SDW_SDCA_MBQ_CTL(reg), (val >> 8) & 0xff);
+	if (ret < 0)
+ return ret;
+
+	return sdw_write(slave, reg, val & 0xff);
+}
+
+static int regmap_sdw_mbq_read(void *context, unsigned int reg, unsigned int *val)
+{
+	struct device *dev = context;
+	struct sdw_slave *slave = dev_to_sdw_dev(dev);
+	int read0;
+	int read1;
+
+	read0 = sdw_read(slave, reg);
+	if (read0 < 0)
+ return read0;
+
+	read1 = sdw_read(slave, SDW_SDCA_MBQ_CTL(reg));
+	if (read1 < 0)
+ return read1;
+
+	*val = (read1 << 8) | read0;
+
+	return 0;
+}
+
+static struct regmap_bus regmap_sdw_mbq = {
+	.reg_read = regmap_sdw_mbq_read,
+	.reg_write = regmap_sdw_mbq_write,
+	.reg_format_endian_default = REGMAP_ENDIAN_LITTLE,
+	.val_format_endian_default = REGMAP_ENDIAN_LITTLE,
+};
+
+static int regmap_sdw_mbq_config_check(const struct regmap_config *config)
+{
+	/* MBQ-based controls are only 16-bits for now */
+	if (config->val_bits != 16)
+ return -EOPNOTSUPP;
+
+	/* Registers are 32 bits wide */
+	if (config->reg_bits != 32)
+ return -EOPNOTSUPP;
+
+	if (config->pad_bits != 0)
+ return -EOPNOTSUPP;
+
+	return 0;
+}
+
+struct regmap *__regmap_init_sdw_mbq(struct sdw_slave *sdw,
+ const struct regmap_config *config,
+ struct lock_class_key *lock_key,
+ const char *lock_name)
+{
+	int ret;
+
+	ret = regmap_sdw_mbq_config_check(config);
+	if (ret)
+ return ERR_PTR(ret);
+
+	return __regmap_init(&sdw->dev, &regmap_sdw_mbq,
+ &sdw->dev, config, lock_key, lock_name);
+}
+EXPORT_SYMBOL_GPL(__regmap_init_sdw_mbq);
+
+struct regmap *__devm_regmap_init_sdw_mbq(struct sdw_slave *sdw,
+ const struct regmap_config *config,
+ struct lock_class_key *lock_key,
+ const char *lock_name)
+{
+	int ret;
+
+	ret = regmap_sdw_mbq_config_check(config);
+	if (ret)
+ return ERR_PTR(ret);
+
+	return __devm_regmap_init(&sdw->dev, &regmap_sdw_mbq,
+ &sdw->dev, config, lock_key, lock_name);
+}
+EXPORT_SYMBOL_GPL(__devm_regmap_init_sdw_mbq);
+
+MODULE_DESCRIPTION("Regmap SoundWire Module");
+MODULE_LICENSE("GPL v2");

drivers/base/regmap/regmap-sdw.c

@@ -2,8 +2,10 @@
 // Copyright(c) 2015-17 Intel Corporation.
 
 #include <linux/device.h>
+#include <linux/errno.h>
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
+#include <linux/regmap.h>
 #include <linux/soundwire/sdw.h>
 #include "internal.h"
 
@@ -40,14 +42,14 @@ static int regmap_sdw_config_check(const struct regmap_config *config)
 {
 	/* All register are 8-bits wide as per MIPI Soundwire 1.0 Spec */
 	if (config->val_bits != 8)
- return -ENOTSUPP;
+ return -EOPNOTSUPP;
 
 	/* Registers are 32 bits wide */
 	if (config->reg_bits != 32)
- return -ENOTSUPP;
+ return -EOPNOTSUPP;
 
 	if (config->pad_bits != 0)
- return -ENOTSUPP;
+ return -EOPNOTSUPP;
 
 	return 0;
 }

include/linux/regmap.h

@@ -567,6 +567,10 @@ struct regmap *__regmap_init_sdw(struct sdw_slave *sdw,
  const struct regmap_config *config,
  struct lock_class_key *lock_key,
  const char *lock_name);
+struct regmap *__regmap_init_sdw_mbq(struct sdw_slave *sdw,
+ const struct regmap_config *config,
+ struct lock_class_key *lock_key,
+ const char *lock_name);
 
 struct regmap *__devm_regmap_init(struct device *dev,
  const struct regmap_bus *bus,
@@ -612,6 +616,10 @@ struct regmap *__devm_regmap_init_sdw(struct sdw_slave *sdw,
  const struct regmap_config *config,
  struct lock_class_key *lock_key,
  const char *lock_name);
+struct regmap *__devm_regmap_init_sdw_mbq(struct sdw_slave *sdw,
+ const struct regmap_config *config,
+ struct lock_class_key *lock_key,
+ const char *lock_name);
 struct regmap *__devm_regmap_init_slimbus(struct slim_device *slimbus,
  const struct regmap_config *config,
  struct lock_class_key *lock_key,
@@ -806,6 +814,18 @@ bool regmap_ac97_default_volatile(struct device *dev, unsigned int reg);
 	__regmap_lockdep_wrapper(__regmap_init_sdw, #config, \
  sdw, config)
 
+/**
+ * regmap_init_sdw_mbq() - Initialise register map
+ *
+ * @sdw: Device that will be interacted with
+ * @config: Configuration for register map
+ *
+ * The return value will be an ERR_PTR() on error or a valid pointer to
+ * a struct regmap.
+ */
+#define regmap_init_sdw_mbq(sdw, config) \
+	__regmap_lockdep_wrapper(__regmap_init_sdw_mbq, #config, \
+ sdw, config)
 
 /**
  * devm_regmap_init() - Initialise managed register map

include/linux/soundwire/sdw_registers.h

@@ -327,5 +327,6 @@
  ((ch) & 0x07))
 
 #define SDW_SDCA_MBQ_CTL(reg) ((reg) | BIT(13))
+#define SDW_SDCA_NEXT_CTL(reg) ((reg) | BIT(14))
 
 #endif /* __SDW_REGISTERS_H */