linux-kernel - [PATCH 3/8] regmap: Add SPI bus support

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Message-Id: <1308768353-19372-3-git-send-email-broonie@opensource.wolfsonmicro.com>
Date:	Wed, 22 Jun 2011 19:45:48 +0100
From:	Mark Brown <broonie@...nsource.wolfsonmicro.com>
To:	linux-kernel@...r.kernel.org
Cc:	Dimitris Papastamos <dp@...nsource.wolfsonmicro.com>,
	Samuel Ortiz <sameo@...ux.intel.com>,
	Liam Girdwood <lrg@...com>,
	Lars-Peter Clausen <lars@...afoo.de>,
	Graeme Gregory <gg@...mlogic.co.uk>,
	Mark Brown <broonie@...nsource.wolfsonmicro.com>
Subject: [PATCH 3/8] regmap: Add SPI bus support

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@...nsource.wolfsonmicro.com>
---
 drivers/regmap/Makefile     |    1 +
 drivers/regmap/regmap-spi.c |   75 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 76 insertions(+), 0 deletions(-)
 create mode 100644 drivers/regmap/regmap-spi.c

diff --git a/drivers/regmap/Makefile b/drivers/regmap/Makefile
index 641c20a..74c6680 100644
--- a/drivers/regmap/Makefile
+++ b/drivers/regmap/Makefile
@@ -1,2 +1,3 @@
 obj-$(CONFIG_REGMAP) += regmap.o
 obj-$(CONFIG_I2C) += regmap-i2c.o
+obj-$(CONFIG_SPI) += regmap-spi.o
diff --git a/drivers/regmap/regmap-spi.c b/drivers/regmap/regmap-spi.c
new file mode 100644
index 0000000..227ab76
--- /dev/null
+++ b/drivers/regmap/regmap-spi.c
@@ -0,0 +1,75 @@
+/*
+ * Register map access API - SPI support
+ *
+ * Copyright 2011 Wolfson Microelectronics plc
+ *
+ * Author: Mark Brown <broonie@...nsource.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>
+
+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[0], &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_bit = 8,
+};
+
+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

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