regmap: Add I2C bus support

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@ti.com>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Grant Likely <grant.likely@secretlab.ca>

4 files changed, 124 insertions, 0 deletions

diff --git a/drivers/base/regmap/Kconfig b/drivers/base/regmap/Kconfig
index fc0eb1d484dd..03cf1abed401 100644
--- a/drivers/base/regmap/Kconfig
+++ b/drivers/base/regmap/Kconfig
@@ -3,4 +3,8 @@
 # subsystems should select the appropriate symbols.
 
 config REGMAP
+        default y if REGMAP_I2C
         bool
+
+config REGMAP_I2C
+        tristate
diff --git a/drivers/base/regmap/Makefile b/drivers/base/regmap/Makefile
index 7532e13e0f00..ee5109d20f4e 100644
--- a/drivers/base/regmap/Makefile
+++ b/drivers/base/regmap/Makefile
@@ -1 +1,2 @@
 obj-$(CONFIG_REGMAP) += regmap.o
+obj-$(CONFIG_REGMAP_I2C) += regmap-i2c.o
diff --git a/drivers/base/regmap/regmap-i2c.c b/drivers/base/regmap/regmap-i2c.c
new file mode 100644
index 000000000000..c2231ff06cbc
--- /dev/null
+++ b/drivers/base/regmap/regmap-i2c.c
@@ -0,0 +1,115 @@
+/*
+ * Register map access API - I2C support
+ *
+ * Copyright 2011 Wolfson Microelectronics plc
+ *
+ * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/regmap.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/init.h>
+
+static int regmap_i2c_write(struct device *dev, const void *data, size_t count)
+{
+        struct i2c_client *i2c = to_i2c_client(dev);
+        int ret;
+
+        ret = i2c_master_send(i2c, data, count);
+        if (ret == count)
+                return 0;
+        else if (ret < 0)
+                return ret;
+        else
+                return -EIO;
+}
+
+static int regmap_i2c_gather_write(struct device *dev,
+                                   const void *reg, size_t reg_size,
+                                   const void *val, size_t val_size)
+{
+        struct i2c_client *i2c = to_i2c_client(dev);
+        struct i2c_msg xfer[2];
+        int ret;
+
+        /* If the I2C controller can't do a gather tell the core, it
+         * will substitute in a linear write for us.
+         */
+        if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_PROTOCOL_MANGLING))
+                return -ENOTSUPP;
+
+        xfer[0].addr = i2c->addr;
+        xfer[0].flags = 0;
+        xfer[0].len = reg_size;
+        xfer[0].buf = (void *)reg;
+
+        xfer[1].addr = i2c->addr;
+        xfer[1].flags = I2C_M_NOSTART;
+        xfer[1].len = val_size;
+        xfer[1].buf = (void *)val;
+
+        ret = i2c_transfer(i2c->adapter, xfer, 2);
+        if (ret == 2)
+                return 0;
+        if (ret < 0)
+                return ret;
+        else
+                return -EIO;
+}
+
+static int regmap_i2c_read(struct device *dev,
+                           const void *reg, size_t reg_size,
+                           void *val, size_t val_size)
+{
+        struct i2c_client *i2c = to_i2c_client(dev);
+        struct i2c_msg xfer[2];
+        int ret;
+
+        xfer[0].addr = i2c->addr;
+        xfer[0].flags = 0;
+        xfer[0].len = reg_size;
+        xfer[0].buf = (void *)reg;
+
+        xfer[1].addr = i2c->addr;
+        xfer[1].flags = I2C_M_RD;
+        xfer[1].len = val_size;
+        xfer[1].buf = val;
+
+        ret = i2c_transfer(i2c->adapter, xfer, 2);
+        if (ret == 2)
+                return 0;
+        else if (ret < 0)
+                return ret;
+        else
+                return -EIO;
+}
+
+static struct regmap_bus regmap_i2c = {
+        .type = &i2c_bus_type,
+        .write = regmap_i2c_write,
+        .gather_write = regmap_i2c_gather_write,
+        .read = regmap_i2c_read,
+        .owner = THIS_MODULE,
+};
+
+/**
+ * regmap_init_i2c(): Initialise register map
+ *
+ * @i2c: 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.
+ */
+struct regmap *regmap_init_i2c(struct i2c_client *i2c,
+                               const struct regmap_config *config)
+{
+        return regmap_init(&i2c->dev, &regmap_i2c, config);
+}
+EXPORT_SYMBOL_GPL(regmap_init_i2c);
+
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index a26c1d001401..5ba61f22c703 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -17,6 +17,8 @@
 #include <linux/list.h>
 #include <linux/module.h>
 
+struct i2c_client;
+
 struct regmap_config {
         int reg_bits;
         int val_bits;
@@ -59,6 +61,8 @@ struct regmap_bus {
 struct regmap *regmap_init(struct device *dev,
                            const struct regmap_bus *bus,
                            const struct regmap_config *config);
+struct regmap *regmap_init_i2c(struct i2c_client *i2c,
+                               const struct regmap_config *config);
 void regmap_exit(struct regmap *map);
 int regmap_write(struct regmap *map, unsigned int reg, unsigned int val);
 int regmap_raw_write(struct regmap *map, unsigned int reg,