[PATCH 3/4] regmap: Add SPI bus support

Mark Brown
2011-07-15T06:23:35Z

We initialise at postcore_initcall() so that we are available before users
- some users such as PMICs initialise very early. We won't actually try to
use any of the bus until a device initialises a register map.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@ti.com>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
---
drivers/spi/Kconfig | 4 ++
drivers/spi/Makefile | 1 +
drivers/spi/spi-regmap.c | 76 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 81 insertions(+), 0 deletions(-)
create mode 100644 drivers/spi/spi-regmap.c

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index de35c3a..1c689a8 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -43,12 +43,16 @@ config SPI_MASTER
# boolean "SPI Master Support"
boolean
default SPI
+ select SPI_REGMAP if REGMAP
help
If your system has an master-capable SPI controller (which
provides the clock and chipselect), you can enable that
controller and the protocol drivers for the SPI slave chips
that are connected.

+config SPI_REGMAP
+ boolean
+
if SPI_MASTER

comment "SPI Master Controller Drivers"
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 0f8c69b..52dcf27 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -7,6 +7,7 @@ ccflags-$(CONFIG_SPI_DEBUG) := -DDEBUG
# small core, mostly translating board-specific
# config declarations into driver model code
obj-$(CONFIG_SPI_MASTER) += spi.o
+obj-$(CONFIG_SPI_REGMAP) += spi-regmap.o

# SPI master controller drivers (bus)
obj-$(CONFIG_SPI_ALTERA) += spi_altera.o
diff --git a/drivers/spi/spi-regmap.c b/drivers/spi/spi-regmap.c
new file mode 100644
index 0000000..ea9072e
--- /dev/null
+++ b/drivers/spi/spi-regmap.c
@@ -0,0 +1,76 @@
+/*
+ * 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];
+
+ spi_message_init(&m);
+
+ memset(&t, 0, sizeof(t));
+
+ t[0].tx_buf = reg;
+ t[0].len = reg_len;
+ spi_message_add_tail(&t[0], &m);
+
+ t[1].tx_buf = val;
+ t[1].len = val_len;
+ 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,
+};
+
+static int __init regmap_spi_init(void)
+{
+ regmap_add_bus(&regmap_spi);
+ return 0;
+}
+postcore_initcall(regmap_spi_init);
+
+static void __exit regmap_spi_exit(void)
+{
+ regmap_del_bus(&regmap_spi);
+}
+module_exit(regmap_spi_exit);
--
1.7.5.4