regmap: Add SPI 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>

3 files changed, 77 insertions, 1 deletions

diff --git a/drivers/base/regmap/Kconfig b/drivers/base/regmap/Kconfig
index 03cf1abed401..fabbf6cc5367 100644
--- a/drivers/base/regmap/Kconfig
+++ b/drivers/base/regmap/Kconfig
@@ -3,8 +3,11 @@
 # subsystems should select the appropriate symbols.
 
 config REGMAP
-        default y if REGMAP_I2C
+        default y if (REGMAP_I2C || REGMAP_SPI)
         bool
 
 config REGMAP_I2C
         tristate
+
+config REGMAP_SPI
+        tristate
diff --git a/drivers/base/regmap/Makefile b/drivers/base/regmap/Makefile
index ee5109d20f4e..f476f4571295 100644
--- a/drivers/base/regmap/Makefile
+++ b/drivers/base/regmap/Makefile
@@ -1,2 +1,3 @@
 obj-$(CONFIG_REGMAP) += regmap.o
 obj-$(CONFIG_REGMAP_I2C) += regmap-i2c.o
+obj-$(CONFIG_REGMAP_SPI) += regmap-spi.o
diff --git a/drivers/base/regmap/regmap-spi.c b/drivers/base/regmap/regmap-spi.c
new file mode 100644
index 000000000000..4deba0621bc7
--- /dev/null
+++ b/drivers/base/regmap/regmap-spi.c
@@ -0,0 +1,72 @@
+/*
+ * Register map access API - SPI 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/spi/spi.h>
+#include <linux/init.h>
+
+static int regmap_spi_write(struct device *dev, const void *data, size_t count)
+{
+        struct spi_device *spi = to_spi_device(dev);
+
+        return spi_write(spi, data, count);
+}
+
+static int regmap_spi_gather_write(struct device *dev,
+                                   const void *reg, size_t reg_len,
+                                   const void *val, size_t val_len)
+{
+        struct spi_device *spi = to_spi_device(dev);
+        struct spi_message m;
+        struct spi_transfer t[2] = { { .tx_buf = reg, .len = reg_len, },
+                                     { .tx_buf = val, .len = val_len, }, };
+
+        spi_message_init(&m);
+        spi_message_add_tail(&t[0], &m);
+        spi_message_add_tail(&t[1], &m);
+
+        return spi_sync(spi, &m);
+}
+
+static int regmap_spi_read(struct device *dev,
+                           const void *reg, size_t reg_size,
+                           void *val, size_t val_size)
+{
+        struct spi_device *spi = to_spi_device(dev);
+
+        return spi_write_then_read(spi, reg, reg_size, val, val_size);
+}
+
+static struct regmap_bus regmap_spi = {
+        .type = &spi_bus_type,
+        .write = regmap_spi_write,
+        .gather_write = regmap_spi_gather_write,
+        .read = regmap_spi_read,
+        .owner = THIS_MODULE,
+        .read_flag_mask = 0x80,
+};
+
+/**
+ * regmap_init_spi(): Initialise register map
+ *
+ * @spi: 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_spi(struct spi_device *spi,
+                               const struct regmap_config *config)
+{
+        return regmap_init(&spi->dev, &regmap_spi, config);
+}
+EXPORT_SYMBOL_GPL(regmap_init_spi);