regmap: add i3c bus support

Add basic support for i3c bus.
This is a simple implementation that only give support
for SDR Read and Write commands.

Signed-off-by: Vitor Soares <vitor.soares@synopsys.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

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)
+	default y if (REGMAP_I2C || REGMAP_SPI || REGMAP_SPMI || REGMAP_W1 || REGMAP_AC97 || REGMAP_MMIO || REGMAP_IRQ || REGMAP_I3C)
 	select IRQ_DOMAIN if REGMAP_IRQ
 	bool
 
@@ -49,3 +49,7 @@ config REGMAP_SOUNDWIRE
 config REGMAP_SCCB
 	tristate
 	depends on I2C
+
+config REGMAP_I3C
+	tristate
+	depends on I3C

drivers/base/regmap/Makefile

@@ -16,3 +16,4 @@ obj-$(CONFIG_REGMAP_IRQ) += regmap-irq.o
 obj-$(CONFIG_REGMAP_W1) += regmap-w1.o
 obj-$(CONFIG_REGMAP_SOUNDWIRE) += regmap-sdw.o
 obj-$(CONFIG_REGMAP_SCCB) += regmap-sccb.o
+obj-$(CONFIG_REGMAP_I3C) += regmap-i3c.o

drivers/base/regmap/regmap-i3c.c

@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2018 Synopsys, Inc. and/or its affiliates.
+
+#include <linux/regmap.h>
+#include <linux/i3c/device.h>
+#include <linux/i3c/master.h>
+#include <linux/module.h>
+
+static int regmap_i3c_write(void *context, const void *data, size_t count)
+{
+	struct device *dev = context;
+	struct i3c_device *i3c = dev_to_i3cdev(dev);
+	struct i3c_priv_xfer xfers[] = {
+		{
+			.rnw = false,
+			.len = count,
+			.data.out = data,
+		},
+	};
+
+	return i3c_device_do_priv_xfers(i3c, xfers, 1);
+}
+
+static int regmap_i3c_read(void *context,
+			   const void *reg, size_t reg_size,
+			   void *val, size_t val_size)
+{
+	struct device *dev = context;
+	struct i3c_device *i3c = dev_to_i3cdev(dev);
+	struct i3c_priv_xfer xfers[2];
+
+	xfers[0].rnw = false;
+	xfers[0].len = reg_size;
+	xfers[0].data.out = reg;
+
+	xfers[1].rnw = true;
+	xfers[1].len = val_size;
+	xfers[1].data.in = val;
+
+	return i3c_device_do_priv_xfers(i3c, xfers, 2);
+}
+
+static struct regmap_bus regmap_i3c = {
+	.write = regmap_i3c_write,
+	.read = regmap_i3c_read,
+};
+
+struct regmap *__devm_regmap_init_i3c(struct i3c_device *i3c,
+				      const struct regmap_config *config,
+				      struct lock_class_key *lock_key,
+				      const char *lock_name)
+{
+	return __devm_regmap_init(&i3c->dev, &regmap_i3c, &i3c->dev, config,
+				  lock_key, lock_name);
+}
+EXPORT_SYMBOL_GPL(__devm_regmap_init_i3c);
+
+MODULE_AUTHOR("Vitor Soares <vitor.soares@synopsys.com>");
+MODULE_DESCRIPTION("Regmap I3C Module");
+MODULE_LICENSE("GPL v2");

include/linux/regmap.h

@@ -25,6 +25,7 @@ struct module;
 struct clk;
 struct device;
 struct i2c_client;
+struct i3c_device;
 struct irq_domain;
 struct slim_device;
 struct spi_device;
@@ -624,6 +625,10 @@ struct regmap *__devm_regmap_init_slimbus(struct slim_device *slimbus,
 				 const struct regmap_config *config,
 				 struct lock_class_key *lock_key,
 				 const char *lock_name);
+struct regmap *__devm_regmap_init_i3c(struct i3c_device *i3c,
+				 const struct regmap_config *config,
+				 struct lock_class_key *lock_key,
+				 const char *lock_name);
 /*
  * Wrapper for regmap_init macros to include a unique lockdep key and name
  * for each call. No-op if CONFIG_LOCKDEP is not set.
@@ -982,6 +987,21 @@ bool regmap_ac97_default_volatile(struct device *dev, unsigned int reg);
 #define devm_regmap_init_slimbus(slimbus, config)			\
 	__regmap_lockdep_wrapper(__devm_regmap_init_slimbus, #config,	\
 				slimbus, config)
+
+/**
+ * devm_regmap_init_i3c() - Initialise managed register map
+ *
+ * @i3c: 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.  The regmap will be automatically freed by the
+ * device management code.
+ */
+#define devm_regmap_init_i3c(i3c, config)				\
+	__regmap_lockdep_wrapper(__devm_regmap_init_i3c, #config,	\
+				i3c, config)
+
 int regmap_mmio_attach_clk(struct regmap *map, struct clk *clk);
 void regmap_mmio_detach_clk(struct regmap *map);
 void regmap_exit(struct regmap *map);